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Calsavara, Vinicius F., Eder A. Milani, Eduardo Bertolli, and Vera Tomazella. "Long-term frailty modeling using a non-proportional hazards model: Application with a melanoma dataset." Statistical Methods in Medical Research 29, no. 8 (November 6, 2019): 2100–2118. http://dx.doi.org/10.1177/0962280219883905.
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The semiparametric Cox regression model is often fitted in the modeling of survival data. One of its main advantages is the ease of interpretation, as long as the hazards rates for two individuals do not vary over time. In practice the proportionality assumption of the hazards may not be true in some situations. In addition, in several survival data is common a proportion of units not susceptible to the event of interest, even if, accompanied by a sufficiently large time, which is so-called immune, “cured,” or not susceptible to the event of interest. In this context, several cure rate models are available to deal with in the long term. Here, we consider the generalized time-dependent logistic (GTDL) model with a power variance function (PVF) frailty term introduced in the hazard function to control for unobservable heterogeneity in patient populations. It allows for non-proportional hazards, as well as survival data with long-term survivors. Parameter estimation was performed using the maximum likelihood method, and Monte Carlo simulation was conducted to evaluate the performance of the models. Its practice relevance is illustrated in a real medical dataset from a population-based study of incident cases of melanoma diagnosed in the state of São Paulo, Brazil.
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Bělasková, Silvie, and Eva Fiserová. "Improvement of the accuracy in testing the effect in the cox proportional hazards model using higher order approximations." Filomat 31, no. 18 (2017): 5591–601. http://dx.doi.org/10.2298/fil1718591b.
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Small-sample properties of the likelihood ratio test, the Wald test and the score test about significance of the effect in the Cox proportional hazards model for the right-censored and left-truncated data are investigated. These are large-sample tests, and, therefore, these are only approximate tests and they do not necessary maintain chosen significance level. Consequently, the p-value can be inaccurate as well. Higher order approximations of the likelihood function based on the Barndorff-Nielsen formula and the Lugannani-Rice formula are used in order to improve the accuracy of statistical inferences. The accuracy of these tests together with proposed approximations are compared by means of simulations under conditions of decreasing the sample size, and increasing proportion of right-censored and left-truncated data in the Cox model with the exponential and the Weibull distribution of the baseline hazard function. The results show that higher order approximations based on the Lugannani-Rice and the Barndorff-Nielsen formulas in combination with the Wald statistic improve the accuracy.
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Li, Jinchao, Lin Chen, Yuwei Xiang, and Ming Xu. "Research on Influential Factors of PM2.5 within the Beijing-Tianjin-Hebei Region in China." Discrete Dynamics in Nature and Society 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/6375391.
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Air pollutant emissions are problematic hazards in China, especially in the Beijing-Tianjin-Hebei region. In this paper, we use fishbone method to set up the influential factor set of PM2.5 qualitatively. Then we use Spearman rank correlation test and panel data regression model to analyze the data of Beijing-Tianjin-Hebei region from 2012 to 2015 quantitatively. The results show that population density, energy consumption per unit area, concrete production per unit area, industrial proportion, transportation volume per unit area, new construction areas per unit area, road construction length per unit area, and coal consumption proportion are all positively correlated with PM2.5. The proportion of electricity consumption is negatively correlated with PM2.5. Among them, population density, industrial proportion, transportation volume, energy consumption per unit area, and the proportion of electricity consumption have a pivotal influence on PM2.5. At last, we give some suggestions to solve the hazard of PM2.5 in Beijing-Tianjin-Hebei region.
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Tang, Haijing, Guo Chen, Yu Kang, and Xu Yang. "Application of Data Science Technology on Research of Circulatory System Disease Prediction Based on a Prospective Cohort." Algorithms 11, no. 10 (October 20, 2018): 162. http://dx.doi.org/10.3390/a11100162.
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Chronic diseases represented by circulatory diseases have gradually become the main types of diseases affecting the health of our population. Establishing a circulatory system disease prediction model to predict the occurrence of diseases and controlling them is of great significance to the health of our population. This article is based on the prospective population cohort data of chronic diseases in China, based on the existing medical cohort studies, the Kaplan–Meier method was used for feature selection, and the traditional medical analysis model represented by the Cox proportional hazards model was used and introduced. Support vector machine research methods in machine learning establish circulatory system disease prediction models. This paper also attempts to introduce the proportion of the explanation variation (PEV) and the shrinkage factor to improve the Cox proportional hazards model; and the use of Particle Swarm Optimization (PSO) algorithm to optimize the parameters of SVM model. Finally, the experimental verification of the above prediction models is carried out. This paper uses the model training time, Accuracy rate(ACC), the area under curve (AUC)of the Receiver Operator Characteristic curve (ROC) and other forecasting indicators. The experimental results show that the PSO-SVM-CSDPC disease prediction model and the S-Cox-CSDPC circulation system disease prediction model have the advantages of fast model solving speed, accurate prediction results and strong generalization ability, which are helpful for the intervention and control of chronic diseases.
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Alipour, Abbas, Abolghasem Shokri, Fatemeh Yasari, and Soheila Khodakarim. "Introduction to Competing Risk Model in the Epidemiological Research." International Journal of Epidemiologic Research 5, no. 3 (September 15, 2018): 98–102. http://dx.doi.org/10.15171/ijer.2018.21.
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Background and aims: Chronic kidney disease (CKD) is a public health challenge worldwide, with adverse consequences of kidney failure, cardiovascular disease (CVD), and premature death. The CKD leads to the end-stage of renal disease (ESRD) if late/not diagnosed. Competing risk modeling is a major issue in epidemiology research. In epidemiological study, sometimes, inappropriate methods (i.e. Kaplan-Meier method) have been used to estimate probabilities for an event of interest in the presence of competing risks. In these situations, competing risk analysis is preferred to other models in survival analysis studies. The purpose of this study was to describe the bias resulting from the use of standard survival analysis to estimate the survival of a patient with ESRD and to provide alternate statistical methods considering the competing risk. Methods: In this retrospective study, 359 patients referred to the hemodialysis department of Shahid Ayatollah Ashrafi Esfahani hospital in Tehran, and underwent continuous hemodialysis for at least three months. Data were collected through patient’s medical history contained in the records (during 2011-2017). To evaluate the effects of research factors on the outcome, cause-specific hazard model and competing risk models were fitted. The data were analyzed using Stata (a general-purpose statistical software package) software, version 14 and SPSS software, version 21, through descriptive and analytical statistics. Results: The median duration of follow-up was 3.12 years and mean age at ESRD diagnosis was 66.47 years old. Each year increase in age was associated with a 98% increase in hazard of death. In this study, statistical analysis based on the competing risk model showed that age, age of diagnosis, level of education (under diploma), and body mass index (BMI) were significantly associated with death (hazard ratio [HR]=0.98, P<0.001, HR=0.99, P<0.001, HR=2.66, P=0.008, and HR=0.98, P<0.020, respectively). Conclusion: In analysis of competing risk data, it was found that providing both the results of the event of interest and those of competing risks were of importance. The Cox model, which ignored the competing risks, presented the different estimates and results as compared to the proportional sub-distribution hazards model. Thus, it was revealed that in the analysis of competing risks data, the sub-distribution proportion hazards model was more appropriate than the Cox model.
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Lee, Seung-Hwan. "Weighted Log-Rank Statistics for Accelerated Failure Time Model." Stats 4, no. 2 (May 3, 2021): 348–58. http://dx.doi.org/10.3390/stats4020023.
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This paper improves the sensitivity of the Gρ family of weighted log-rank tests for the accelerated failure time model, accommodating realistic alternatives in survival analysis with censored data, such as heavy censoring and crossing hazards. The procedures are based on a weight function with the censoring proportion incorporated as a component. Extensive simulations show that the weight function enhances the performance of the Gρ family, increasing its sensitivity and flexibility. The weight function method is illustrated with an example concerning vaginal cancer.
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Meleth, Sreelatha, Chakrapani Chatla, Venkat R. Katkoori, Billie Anderson, James M. Hardin, Nirag C. Jhala, Al Bartolucci, William E. Grizzle, and Upender Manne. "Comparison of Predicted Probabilities of Proportional Hazards Regression and Linear Discriminant Analysis Methods Using a Colorectal Cancer Molecular Biomarker Database." Cancer Informatics 3 (January 2007): 117693510700300. http://dx.doi.org/10.1177/117693510700300018.
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Background Although a majority of studies in cancer biomarker discovery claim to use proportional hazards regression (PHREG) to the study the ability of a biomarker to predict survival, few studies use the predicted probabilities obtained from the model to test the quality of the model. In this paper, we compared the quality of predictions by a PHREG model to that of a linear discriminant analysis (LDA) in both training and test set settings. Methods The PHREG and LDA models were built on a 491 colorectal cancer (CRC) patient dataset comprised of demographic and clinicopathologic variables, and phenotypic expression of p53 and Bcl-2. Two variable selection methods, stepwise discriminant analysis and the backward selection, were used to identify the final models. The endpoint of prediction in these models was five-year post-surgery survival. We also used linear regression model to examine the effect of bin size in the training set on the accuracy of prediction in the test set. Results The two variable selection techniques resulted in different models when stage was included in the list of variables available for selection. However, the proportion of survivors and non-survivors correctly identified was identical in both of these models. When stage was excluded from the variable list, the error rate for the LDA model was 42% as compared to an error rate of 34% for the PHREG model. Conclusions This study suggests that a PHREG model can perform as well or better than a traditional classifier such as LDA to classify patients into prognostic classes. Also, this study suggests that in the absence of the tumor stage as a variable, Bcl-2 expression is a strong prognostic molecular marker of CRC.
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Tice, Jeffrey A., Diana L. Miglioretti, Chin-Shang Li, Celine M. Vachon, Charlotte C. Gard, and Karla Kerlikowske. "Breast Density and Benign Breast Disease: Risk Assessment to Identify Women at High Risk of Breast Cancer." Journal of Clinical Oncology 33, no. 28 (October 1, 2015): 3137–43. http://dx.doi.org/10.1200/jco.2015.60.8869.
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Purpose Women with proliferative breast lesions are candidates for primary prevention, but few risk models incorporate benign findings to assess breast cancer risk. We incorporated benign breast disease (BBD) diagnoses into the Breast Cancer Surveillance Consortium (BCSC) risk model, the only breast cancer risk assessment tool that uses breast density. Methods We developed and validated a competing-risk model using 2000 to 2010 SEER data for breast cancer incidence and 2010 vital statistics to adjust for the competing risk of death. We used Cox proportional hazards regression to estimate the relative hazards for age, race/ethnicity, family history of breast cancer, history of breast biopsy, BBD diagnoses, and breast density in the BCSC. Results We included 1,135,977 women age 35 to 74 years undergoing mammography with no history of breast cancer; 17% of the women had a prior breast biopsy. During a mean follow-up of 6.9 years, 17,908 women were diagnosed with invasive breast cancer. The BCSC BBD model slightly overpredicted risk (expected-to-observed ratio, 1.04; 95% CI, 1.03 to 1.06) and had modest discriminatory accuracy (area under the receiver operator characteristic curve, 0.665). Among women with proliferative findings, adding BBD to the model increased the proportion of women with an estimated 5-year risk of 3% or higher from 9.3% to 27.8% (P < .001). Conclusion The BCSC BBD model accurately estimates women's risk for breast cancer using breast density and BBD diagnoses. Greater numbers of high-risk women eligible for primary prevention after BBD diagnosis are identified using the BCSC BBD model.
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Nishimura, Jennifer, Audrey Choi, Sharon Kim, and Julian Kim. "Trends in the use of breast-conserving surgery and adjuvant radiation therapy in patients with DCIS: A U.S. population-based analysis from 1996 to 2007." Journal of Clinical Oncology 30, no. 15_suppl (May 20, 2012): 1110. http://dx.doi.org/10.1200/jco.2012.30.15_suppl.1110.
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1031 Background: The treatment for patients with DCIS remains controversial. Current guidelines based upon best available evidence suggest that breast conserving surgery (BCS) followed by adjuvant radiation therapy (RT) result in acceptable local control and breast cancer specific survival. The purpose of this study was to analyze trends in patterns of care as well as identify factors associated with surgery type and use of adjuvant radiation therapy in a select cohort of patients enrolled into the SEER database. Methods: The study included females 18 years and older with focal DCIS and known tumor size of 5 cm or less diagnosed between 1996 and 2007. The Cochran-Armitage trend test was applied to identify trends in the use of BCS and RT over time. Multivariate logistic regression analyses were used to determine factors associated with receiving BCS vs. mastectomy and BCS plus RT vs. BCS alone. Cox proportional hazard model was used to determine associations with breast cancer-specific mortality. Results: Of the 34,233 women with DCIS, 76.59% were treated with BCS. 66.36% of BCS patients received adjuvant RT over the study period. The proportion of women receiving BCS increased from 71.5% in 1996 to 76.9% in 2007 (p<0.0001). Additionally, the proportion of women who underwent BCS and received adjuvant radiation therapy over the same time period increased from 55.3% to 69.7% (p<0.0001). Multivariate analysis demonstrated that year of diagnosis, race, marital status, geographic region, tumor size, tumor grade and comedo necrosis all were significantly associated with the use of adjuvant radiation therapy, but age was not. Cox proportional hazards models did not associate either surgery type or use of adjuvant radiation in patients undergoing BCS with breast cancer-specific mortality. Conclusions: Based upon reporting within the SEER database, the proportion of DCIS patients undergoing BCS and the BCS patients receiving adjuvant radiation increased over the study time period. Surgery type and use of adjuvant radiation therapy in patients with BCS was not associated with decreased risk of breast-cancer specific death in this cohort.
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GHODRATI, BEHZAD, ALIREZA AHMADI, and DIEGO GALAR. "SPARE PARTS ESTIMATION FOR MACHINE AVAILABILITY IMPROVEMENT ADDRESSING ITS RELIABILITY AND OPERATING ENVIRONMENT — CASE STUDY." International Journal of Reliability, Quality and Safety Engineering 20, no. 03 (June 2013): 1340005. http://dx.doi.org/10.1142/s0218539313400056.
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Industrial operation cost analysis shows that, in general, maintenance represents a significant proportion of the overall operating costs. Therefore, the improvement of maintenance follows the final goal of any company, namely, to maximize profit. This paper studies spare parts availability, an issue of the maintenance process, which is an important way to improve production through increased availability of functional machinery and subsequent minimization of the total production cost. Spare parts estimation based on machine reliability characteristics and operating environment is performed. The study uses an improved statistical-reliability (S-R) approach which incorporates the system/machine operating environment information in systems reliability analysis. For this purpose, two methods of Poisson process and renewal process are introduced and discussed. The renewal process model uses a multiple regression type of analysis based on Cox's proportional hazards modeling (PHM). The parametric approaches with baseline Weibull hazard functions and time-independent covariates are considered, and the influence of operating environment factors on this model is analyzed. The outputs represent a significant difference in the required spare parts estimation when considering or ignoring the influence of the relevant system operating environment. The difference is significant in the sense of spare parts forecasting and inventory management which can enhance the parts and consequently machine availability, leading to economical operation and savings.
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Divi, Vasu, Michelle M. Chen, Brian Nussenbaum, Kim F. Rhoads, Davud B. Sirjani, F. Christopher Holsinger, Jennifer L. Shah, and Wendy Hara. "Lymph Node Count From Neck Dissection Predicts Mortality in Head and Neck Cancer." Journal of Clinical Oncology 34, no. 32 (November 10, 2016): 3892–97. http://dx.doi.org/10.1200/jco.2016.67.3863.
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Purpose Multiple smaller studies have demonstrated an association between overall survival and lymph node (LN) count from neck dissection in patients with head and neck cancer. This is a large cohort study to examine these associations by using a national cancer database. Patients and Methods The National Cancer Database was used to identify patients who underwent upfront nodal dissection for mucosal head and neck squamous cell carcinoma between 2004 and 2013. Patients were stratified by LN count into those with < 18 nodes and those with ≥ 18 nodes on the basis of prior work. A multivariable Cox proportional hazards regression model was constructed to predict hazard of mortality. Stratified models predicted hazard of mortality both for patients who were both node negative and node positive. Results There were 45,113 patients with ≥ 18 LNs and 18,865 patients with < 18 LNs examined. The < 18 LN group, compared with the ≥ 18 LN group, had more favorable tumor characteristics, with a lower proportion of T3 and T4 lesions (27.9% v 39.8%), fewer patients with positive nodes (46.6% v 60.5%), and lower rates of extracapsular extension (9.3% v 15.1%). Risk-adjusted Cox models predicting hazard of mortality by LN count showed an 18% increased hazard of death for patients with < 18 nodes examined (hazard ratio [HR] 1.18; 95% CI, 1.13 to 1.22). When stratified by clinical nodal stage, there was an increased hazard of death in both groups (node negative: HR, 1.24; 95% CI, 1.17 to 1.32; node positive: HR, 1.12; 95% CI, 1.05 to 1.19). Conclusion The results of our study demonstrate a significant overall survival advantage in both patients who are clinically node negative and node positive when ≥ 18 LNs are examined after neck dissection, which suggests that LN count is a potential quality metric for neck dissection.
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Ebadi, Yalda, Donald L. Fisher, and Shannon C. Roberts. "Impact of Cognitive Distractions on Drivers’ Hazard Anticipation Behavior in Complex Scenarios." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 9 (May 8, 2019): 440–51. http://dx.doi.org/10.1177/0361198119846463.
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Distraction is one of the main causes of traffic crashes. The effect of cell phones, a major contributor to cognitive distraction, on response time has tested in many simulator studies. Response time is not the only driving skill affected by cell phone conversations, however. Specifically, it is known that cell phone usage contributes to a reduction in hazard anticipation skills at intersections, and there are many other scenarios where cell phone conversations could have a detrimental effect. The objective of this study is to determine whether cognitive distractions associated with cell phone use affect hazard anticipation, not only at intersections but also in other scenarios which contain latent hazards. Twenty-four drivers navigated 18 scenarios on a driving simulator twice, with their eye movements continuously monitored. During one drive, participants performed a hands-free mock cell phone task while driving; on the other drive, they navigated through the virtual world without any additional tasks apart from the primary task of driving. The scenarios were classified into two types: intersection and non-intersection. Using a logistic regression model within the framework of generalized estimation equations, it was determined that the proportion of anticipatory glances toward potential hazards was reduced significantly for all scenarios when drivers were engaged in a mock cell phone task. Perhaps the most disturbing finding is that this was true both at work zones and at marked midblock crosswalks, scenarios which often endanger vulnerable road users. In summary, the study found a negative effect of cognitive distraction on latent hazard anticipation.
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Nadeau-Fredette, Annie-Claire, David W. Johnson, Carmel M. Hawley, Elaine M. Pascoe, Yeoungjee Cho, Philip A. Clayton, Monique Borlace, et al. "Center-Specific Factors Associated with Peritonitis Risk—A Multi-Center Registry Analysis." Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis 36, no. 5 (September 2016): 509–18. http://dx.doi.org/10.3747/pdi.2015.00146.
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Background Previous studies have reported significant variation in peritonitis rates across dialysis centers. Limited evidence is available to explain this variability. The aim of this study was to assess center-level predictors of peritonitis and their relationship with peritonitis rate variations. Methods All incident peritoneal dialysis (PD) patients treated in Australia between October 2003 and December 2013 were included. Data were accessed through the Australia and New Zealand Dialysis and Transplant Registry. The primary outcome was peritonitis rate, evaluated in a mixed effects negative binomial regression model. Peritonitis-free survival was assessed as a secondary outcome in a Cox proportional hazards model. Results Overall, 8,711 incident PD patients from 51 dialysis centers were included in the study. Center-level predictors of lower peritonitis rates included smaller center size, high proportion of PD, low peritoneal equilibration test use at PD start, and low proportion of hospitalization for peritonitis. In contrast, a low proportion of automated PD exposure, high icodextrin exposure and low or high use of antifungal prophylaxis at the time of peritonitis were associated with a higher peritonitis rate. Similar results were obtained for peritonitis-free survival. Overall, accounting for center-level characteristics appreciably decreased peritonitis variability among dialysis centers ( p = 0.02). Conclusion This study identified specific center-level characteristics associated with the variation in peritonitis risk. Whether these factors are directly related to peritonitis risk or surrogate markers for other center characteristics is uncertain and should be validated in further studies.
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HERZIG, KAREN ANN, DAVID MICHAEL PURDIE, WENDY CHANG, ALLISON MARGARET BROWN, CARMEL MARY HAWLEY, SCOTT BRYAN CAMPBELL, JOANNA MARY STURTEVANT, NICOLE MAREE ISBEL, DAVID LAWRENCE NICOL, and DAVID WAYNE JOHNSON. "Is C-Reactive Protein a Useful Predictor of Outcome in Peritoneal Dialysis Patients?" Journal of the American Society of Nephrology 12, no. 4 (April 2001): 814–21. http://dx.doi.org/10.1681/asn.v124814.
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Abstract. An elevated C-reactive protein (CRP) has recently been shown to be strongly predictive of mortality in hemodialysis patients. However, its predictive value in peritoneal dialysis (PD) patients has not been assessed. A cohort of 50 PD patients was followed prospectively for a 3-yr period, after initial determination of CRP. Patients with an elevated CRP (>6 mg/L;n= 29) had significantly reduced plasma prealbumin (0.36 ± 0.02versus0.44 ± 0.03 g/L;P< 0.05), decreased total weekly creatinine clearance (CCr; 52.5 ± 2.3versus63.1 ± 3.2 L/1.73 m2;P< 0.01), and increased left ventricular thickness (1.24 ± 0.05versus1.08 ± 0.06 cm;P< 0.05) at baseline compared with those who had a normal CRP (≤6 mg/L;n= 21). Baseline CRP (log-transformed) correlated weakly with baseline Kt/V, CCr, and pre-albumin. With the use of a multivariate Cox's proportional hazards model to adjust for potential confounding factors, an elevated CRP was predictive of myocardial infarction (adjusted hazard ratio, 4.8; 95% confidence interval [CI], 1.0 to 23;P= 0.048) and tended to be predictive of fatal myocardial infarction (adjusted hazard ratio, 6.0; 95% CI, 0.8 to 43;P= 0.07). However, CRP was not significantly associated with all-cause mortality (adjusted hazard ratio, 2.1; 95% CI,0.8 to 5.4;P= 0.15). In conclusion, CRP elevation occurs in a substantial proportion of PD patients and is independently predictive of future myocardial infarction. Such patients may warrant closer monitoring and attention to modifiable cardiovascular risk factors.
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Hsiao, Pao Ying, June L. Fung, Diane C. Mitchell, Terryl J. Hartman, and Marlene B. Goldman. "Dietary quality, as measured by the Alternative Healthy Eating Index for Pregnancy (AHEI-P), in couples planning their first pregnancy." Public Health Nutrition 22, no. 18 (May 27, 2019): 3385–94. http://dx.doi.org/10.1017/s1368980019001290.
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AbstractObjective:Dietary quality (DQ), as assessed by the Alternative Healthy Eating Index for Pregnancy (AHEI-P), and conception and pregnancy outcomes were evaluated.Design:In this prospective cohort study on couples planning their first pregnancy. Cox proportional hazards regression assessed the relationship between AHEI-P score and clinical pregnancy, live birth and pregnancy loss.Setting:Participants were recruited from the Northeast region of the USA.Participants: Healthy, nulliparous couples (females, n 132; males, n 131; one male did not enrol).Results:There were eighty clinical pregnancies, of which sixty-nine resulted in live births and eleven were pregnancy losses. Mean (sd) female AHEI-P was 71·0 (13·7). Of those who achieved pregnancy, those in the highest tertile of AHEI-P had the greatest proportion of clinical pregnancies; however, this association was not statistically significant (P = 0·41). When the time it took to conceive was considered, females with the highest AHEI-P scores were 20 % and 14 % more likely to achieve clinical pregnancy (model 1: hazard ratio (HR) = 1·20; 95 % CI 0·66, 2·17) and live birth (model 1: HR = 1·14; 95 % CI 0·59, 2·20), respectively. Likelihood of achieving clinical pregnancy and live birth increased when the fully adjusted model, including male AHEI-P score, was examined (clinical pregnancy model 4: HR = 1·55; 95 % CI 0·71, 3·39; live birth model 4: HR = 1·36; 95 % CI 0·59, 3·13).Conclusions:The present study is the first to examine AHEI-P score and achievement of clinical pregnancy. DQ was not significantly related to pregnancy outcomes, even after adjustments for covariates.
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Lee, S. D., J. R. Allegretti, F. Steinwurz, S. B. Connelly, N. Lawendy, J. Paulissen, and K. B. Gecse. "DOP59 Evaluation of the efficacy of tofacitinib as maintenance therapy in patients with Ulcerative Colitis stratified by OCTAVE Sustain baseline endoscopic subscore." Journal of Crohn's and Colitis 15, Supplement_1 (May 1, 2021): S094—S095. http://dx.doi.org/10.1093/ecco-jcc/jjab073.098.
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Abstract Background Tofacitinib is an oral, small molecule JAK inhibitor for the treatment of ulcerative colitis (UC). Efficacy and safety of tofacitinib in patients (pts) with UC were evaluated in two 8-week, Phase 3 induction studies (OCTAVE Induction 1&2), a 52-week, Phase 3 maintenance study (OCTAVE Sustain), and an open-label, long-term extension study. Here, we evaluate tofacitinib efficacy in OCTAVE Sustain (NCT01458574) by baseline Mayo endoscopic subscore (ES). Methods Pts with an OCTAVE Sustain baseline ES of 0 or 1 were included. Proportion of pts achieving efficacy endpoints at Week 52 of OCTAVE Sustain (responders from OCTAVE Induction 1&2; tofacitinib 5 or 10 mg twice daily [BID] or placebo [PBO]) was evaluated in relation to OCTAVE Sustain baseline ES. Using logistic regression, the difference in treatment effect (tofacitinib vs PBO) between baseline ES (0 vs 1) for each efficacy endpoint was assessed. Cox proportional hazards regression was used to model the difference in treatment effect between baseline ES (0 vs 1) for time to treatment failure and loss of response. Results At Week 52 of OCTAVE Sustain, a numerically higher proportion of pts with a baseline ES of 0 achieved remission and endoscopic improvement vs pts with a baseline ES of 1, regardless of tofacitinib dose (Table). Logistic regression analyses showed a larger treatment effect of tofacitinib 5 mg BID at Week 52 in pts with a baseline ES of 0 vs 1 (p=0.0306) for clinical response (Table). Treatment effect of tofacitinib 10 mg BID was not significantly different between baseline ES 0 vs 1 for any endpoint (Table). In tofacitinib 5 mg BID-treated pts, Cox proportional hazards regression showed difference in risk vs PBO to be larger in pts with a baseline ES of 0 vs 1 for treatment failure (p=0.0231) and loss of response (p=0.0209); corresponding differences for 10 mg BID-treated pts were not significant (p=0.9239 and p=0.9613, respectively). Conclusion In general, at Week 52 of OCTAVE Sustain, a higher proportion of tofacitinib-treated pts achieved endpoints with a baseline ES of 0 vs 1. Based on proportions, the treatment effect of tofacitinib 5 mg BID was more evident in pts with a baseline ES of 0 vs 1. This difference in treatment effect related to baseline ES was not observed with tofacitinib 10 mg BID. Baseline ES may be an important factor in predicting outcomes, and suggests that aiming for a deeper remission after induction may allow successful maintenance with tofacitinib 5 mg BID. These analyses were post hoc and limited by the small sample sizes.
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Park, Elizabeth S. "Examining Community College Students’ Progression Through the English as a Second Language Sequence." Community College Review 47, no. 4 (August 13, 2019): 406–33. http://dx.doi.org/10.1177/0091552119867467.
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Objective: Although immigrant students placed in English as a Second Language (ESL) sequence at community colleges are a growing student population, there is a dearth of research focused on these students in college. This study provides descriptive estimates of community college students’ progression through the credit-earning ESL sequence and disaggregates the findings by Generation 1.5/2.0 status. As community colleges seek to better support students whose primary language is not English, this study provides some of the first empirical evidence on who is placing where and how long it takes students to progress through the ESL sequence. Method: This study uses transcript data from a community college in California that enrolls a large proportion of students in the ESL sequence and estimates a Cox proportional hazards model with time to completing English 101 as the dependent variable. Results: Most Generation 1.5/2.0 students who take the ESL placement test start three levels or below college-level English. Furthermore, Generation 1.5/2.0 students attempt and complete English 101 at a lower rate than international students. Results from the Cox proportional hazards model show that international students are more likely to complete English 101 than U.S. citizens at any given point in time. Among the Generation 1.5/2.0 subsample, female permanent residents are more likely to complete English 101 than citizens. Conclusion: The findings suggest a need to reassess the ESL placement process so that all students placed in ESL are able to successfully progress toward college-level English.
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Tellman, Beth, Cody Schank, Bessie Schwarz, Peter D. Howe, and Alex de Sherbinin. "Using Disaster Outcomes to Validate Components of Social Vulnerability to Floods: Flood Deaths and Property Damage across the USA." Sustainability 12, no. 15 (July 27, 2020): 6006. http://dx.doi.org/10.3390/su12156006.
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Social vulnerability indicators seek to identify populations susceptible to hazards based on aggregated sociodemographic data. Vulnerability indices are rarely validated with disaster outcome data at broad spatial scales, making it difficult to develop effective national scale strategies to mitigate loss for vulnerable populations. This paper validates social vulnerability indicators using two flood outcomes: death and damage. Regression models identify sociodemographic factors associated with variation in outcomes from 11,629 non-coastal flood events in the USA (2008–2012), controlling for flood intensity using stream gauge data. We compare models with (i) socioeconomic variables, (ii) the composite social vulnerability index (SoVI), and (iii) flood intensity variables only. The SoVI explains a larger portion of the variance in death (AIC = 2829) and damage (R2 = 0.125) than flood intensity alone (death—AIC = 2894; damage—R2 = 0.089), and models with individual sociodemographic factors perform best (death—AIC = 2696; damage—R2 = 0.229). Socioeconomic variables correlated with death (rural counties with a high proportion of elderly and young) differ from those related to property damage (rural counties with high percentage of Black, Hispanic and Native American populations below the poverty line). Results confirm that social vulnerability influences death and damage from floods in the USA. Model results indicate that social vulnerability models related to specific hazards and outcomes perform better than generic social vulnerability indices (e.g., SoVI) in predicting non-coastal flood death and damage. Hazard- and outcome-specific indices could be used to better direct efforts to ameliorate flood death and damage towards the people and places that need it most. Future validation studies should examine other flood outcomes, such as evacuation, migration and health, across scales.
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Sreedevi, E. P., and P. G. Sankaran. "Statistical methods for estimating cure fraction of COVID-19 patients in India." Model Assisted Statistics and Applications 16, no. 1 (March 25, 2021): 59–64. http://dx.doi.org/10.3233/mas-210515.
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Human race is under the COVID-19 pandemic menace since beginning of the year 2020. Even though the disease is easily transmissible, a massive fraction of the affected people is recovering. Most of the recovered patients will not experience death due to COVID-19, even if they observed for a long period. They can be treated as long term survivors in the context of lifetime data analysis. In this article, we present statistical methods to estimate the proportion of long term survivors (cure fraction) of the COVID-19 patient population in India. The proportional hazards mixture cure model is used to estimate the cure fraction and the effect of the covariates gender and age, on lifetime. We can see that the cure fraction of the COVID-19 patients in India is more than 90%, which is indeed an optimistic information.
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Leclerc, B. S., C. Bégin, E. Cadieux, L. Goulet, N. Leduc, M. J. Kergoat, and P. Lebel. "Risk factors for falling among community-dwelling seniors using home-care services: An extended hazards model with time-dependent covariates and multiple events." Chronic Diseases in Canada 28, no. 4 (2008): 111–20. http://dx.doi.org/10.24095/hpcdp.28.4.01.
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The identification of risk factors for falls in longitudinal studies becomes difficult because of exposures that change during the follow-up and also because individual subjects may experience an event more than once. These issues have been neglected and improper statistical techniques have been used. The typical approaches have been to report the proportion of fallers or the time to first fall. Both avoid the underlying assumption of independence between events and discard pertinent data. We review the existing methods and propose a Cox hazards extension. We exemplify it in the study of potential risk factors associated with all falls in 959 seniors. Finally, we compare the results of the proposed Wei, Lin, & Weissfeld (WLW) method with those of several other techniques. Stable exposure variables measured at baseline and updated time-varying exposures include socio-demographic characteristics, BMI, nutritional risk, alcohol consumption, home hazards, gait and balance, and medications. Results demonstrate that the usual methods of analyzing risk factors for falling are inappropriate, as they produce considerable biases relative to the WLW model using time-dependent covariates. Results also show that modeling for first events may be inefficient, given that the risk of occurrence varies between falls.
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Råman Vinnå, Love, Damien Bouffard, Alfred Wüest, Stéphanie Girardclos, and Nathalie Dubois. "Assessing Subaquatic Mass Movement Hazards: an Integrated Observational and Hydrodynamic Modelling Approach." Water Resources Management 34, no. 13 (September 10, 2020): 4133–46. http://dx.doi.org/10.1007/s11269-020-02660-y.
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Abstract High-resolution lake and reservoir bathymetric surveys can pinpoint locations that may experience underwater landslides (subaquatic sedimentary mass movements). These can pose a risk to underwater and shoreline infrastructure. This paper outlines an approach for using spatial variation in sedimentary patterns to identify areas susceptible to subaquatic mass movements in lakes and reservoirs. This study focusses on Lake Biel (Switzerland), which has experienced a protracted history of upstream alteration of river flow. Altered flow patterns increase risk of unstable sedimentary features and subaquatic mass movements. Data from sediment traps and cores, Acoustic Doppler Current Profilers and results from a 3D hydrodynamic model gave a consistent picture of spatial and temporal variation in weather-related sedimentation. Erosion caused by short-term rain events contributes the largest proportion of sediments to the lake. Strong rain events combine with typical wind patterns to drive lake circulation. The net effect results in preferential sedimentation onto a steeply sloping shelf prone to subaquatic slides. The integrated approach outlined here incorporates short- and long-term sediment dynamics to provide a systematic assessment of lake sedimentation and potential mass movement hazards. This research represents a first step in developing a risk-evaluation tool for aquatic hazard evaluation.
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Khinanti, Aprilia Sekar, Sudarno Sudarno, and Triastuti Wuryandari. "MODEL REGRESI COX PROPORTIONAL HAZARD PADA DATA KETAHANAN HIDUP PASIEN HEMODIALISA." Jurnal Gaussian 10, no. 2 (May 31, 2021): 303–14. http://dx.doi.org/10.14710/j.gauss.v10i2.30958.
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Cox regression is a type of survival analysis that can be implemented with proportional hazard models or duration models. In the survival analysis data, there is a possibility that the data has ties, so it is necessary to use several approaches in estimating the parameters, namely the breslow, efron, and exact approaches. In this study, the Cox proportional hazard regression was used as a method of analysis for knowing the factors that influence the survival time on chronic kidney patients undergoing hemodialysis therapy. Based on the analysis that has been done, the best model is obtained with an exact approach and the factors that influence the survival time of hemodialysis patients are systolic blood pressure, hemoglobin level, and dialysis time. Hemodialysis patients who have high systolic blood pressure have a chance of failing to survive 12,950 times than normal systolic blood pressure.While the hemodialysis patient hemoglobin level increases, the hemodialysis patients chances of failing to survive is 0,6681 times less. Hemodialysis patients who received dialysis therapy with a dialysis time of more than four hours had 0.237 times the chance of failing to survive than patients with a dialysis time of less than or equal to 4 hours.Keywords: Cox Regression ,Survival, Ties, Hemodialysis.
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Kim, Hye Jeong, Ji Cheol Bae, Hyeong Kyu Park, Dong Won Byun, Kyoil Suh, Myung Hi Yoo, Jee Jae Hwan, et al. "Association of triiodothyronine levels with future development of metabolic syndrome in euthyroid middle-aged subjects: a 6-year retrospective longitudinal study." European Journal of Endocrinology 176, no. 4 (April 2017): 443–52. http://dx.doi.org/10.1530/eje-16-0734.
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Background Several cross-sectional studies have reported that thyroid hormone levels are associated with cardiovascular risk markers and metabolic syndrome (MetS) even in euthyroid subjects. However, the prognostic role of serum thyroid hormone levels in the risk of incident MetS has not been elucidated. Aim We aimed to investigate the associations of baseline serum thyroid hormone levels with the development of MetS in healthy subjects. Methods This 6-year, cross-sectional, longitudinal and follow-up study was conducted in 12 037 euthyroid middle-aged subjects without MetS subjected to comprehensive health examinations. Subjects were grouped according to total triiodothyronine (T3) quartiles. The hazard ratio (HR) for the development of MetS according to T3 quartiles was estimated using Cox proportional hazards model. Results During the 6-year period, 3544 incident cases of MetS (29%) were identified. The proportion of subjects with incident MetS increased across the T3 quartiles (P for trend <0.001). The HR and 95% confidence interval (CI) for the development of MetS were significantly higher in the highest T3 quartile compared with the lowest T3 quartile even after adjusting for confounding variables including gender, age and smoking (HR: 1.238, 95% CI: 1.128–1.358, P < 0.001). Conclusion In euthyroid middle-aged subjects, serum T3 levels are associated with increased risk for future development of MetS.
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O'Kelly, Cian J., Abhaya V. Kulkarni, Peter C. Austin, M. Christopher Wallace, and David Urbach. "The impact of therapeutic modality on outcomes following repair of ruptured intracranial aneurysms: an administrative data analysis." Journal of Neurosurgery 113, no. 4 (October 2010): 795–801. http://dx.doi.org/10.3171/2009.9.jns081645.
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Object Enrolling a selected sample of ruptured intracranial aneurysms, the International Subarachnoid Aneurysm Trial (ISAT) found endovascular coiling to be superior to microsurgical clipping. The performance of coiling in a more general population of ruptured aneurysms has not been adequately studied. Methods Using provincial administrative data from Ontario, the authors conducted a retrospective cohort study of adult patients with subarachnoid hemorrhage (SAH) who underwent aneurysm repair. The exposure was defined as endovascular versus surgical aneurysm repair. The prespecified primary outcome was time to death or readmission for SAH. Data from the entire cohort were analyzed using a multivariable adjusted Cox proportional hazards model. Propensity scores were used to compare a matched subgroup of patients with aneurysms who had similar baseline characteristics. The potential impact of unmeasured confounding was assessed using sensitivity analysis. Results Between 1995 and 2004, 2342 aneurysms were clipped and 778 were coiled in Ontario. The proportion of aneurysms treated by coiling increased steadily over time. In the adjusted analysis of the entire cohort, endovascular coiling was associated with a significantly increased hazard of death or SAH readmission (hazard ratio 1.25 [95% CI 1.00–1.55], p = 0.04). Similar results were obtained from the propensity score matched analysis (hazard ratio 1.25 [95% CI 1.04–1.50], p = 0.02). Measures of procedural morbidity and mortality were not significantly different between groups. Conclusions The results of the current analysis call into question the generalizability of the ISAT to all ruptured aneurysms. Given the limitations inherent in this form of analysis, further clinical studies—rigorously assessing the performance of endovascular therapy in patients with non-ISAT-like aneurysms—are indicated.
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Wierda, William G., Susan O'Brien, Xuemei Wang, Stefan Faderl, Alessandra Ferrajoli, Kim-Anh Do, Jorge Cortes, et al. "Prognostic nomogram and index for overall survival in previously untreated patients with chronic lymphocytic leukemia." Blood 109, no. 11 (June 1, 2007): 4679–85. http://dx.doi.org/10.1182/blood-2005-12-051458.
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Abstract The clinical course for patients with chronic lymphocytic leukemia is extremely heterogeneous. The Rai and Binet staging systems have been used to risk-stratify patients; most patients present with early-stage disease. We evaluated a group of previously untreated patients with chronic lymphocytic leukemia (CLL) at initial presentation to University of Texas M. D. Anderson Cancer Center to identify independent characteristics that predict for overall survival. Clinical and routine laboratory characteristics for 1674 previously untreated patients who presented for evaluation of CLL from 1981 to 2004 were included. Univariate and multivariate analyses identified several patient characteristics at presentation that predicted for overall survival in previously untreated patients with CLL. A multivariate Cox proportional hazards model was developed, including the following independent characteristics: age, β-2 microglobulin, absolute lymphocyte count, sex, Rai stage, and number of involved lymph node groups. Inclusion of patients from a single institution and the proportion of patients younger than 65 years may limit this model. A weighted prognostic model, or nomogram, predictive for overall survival was constructed using these 6 characteristics for 5- and 10-year survival probability and estimated median survival time. This prognostic model may help patients and clinicians in clinical decision making as well as in clinical research and clinical trial design.
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Crichton, Nicola. "Cox Proportional Hazards Model." Journal of Clinical Nursing 11, no. 6 (November 2002): 723. http://dx.doi.org/10.1046/j.1365-2702.2002.00714.x.
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Farr, Amanda M., David M. Smith, Jacqueline A. Pesa, and Zhun Cao. "Follow-up Care among Medicaid Patients with Schizophrenia treated with Antipsychotics in the Inpatient Setting." Journal of Health Economics and Outcomes Research 2, no. 1 (October 2, 2014): 29–40. http://dx.doi.org/10.36469/9882.
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Background: For patients with schizophrenia, the transition from inpatient hospitalization to outpatient care presents a challenge to providing continuous care. Lapses in care during this time period can result in poor clinical outcomes. To date, there is little information regarding the association between inpatient antipsychotic treatment and outpatient care. Objectives: The objectives of this study were to describe trends in and identify factors associated with post-discharge follow-up outpatient care among Medicaid enrollees with schizophrenia treated with antipsychotics. Methods: Adults administered oral or long-acting injectable antipsychotic medication during a hospitalization for schizophrenia were identified in the linked MarketScan® Hospital Drug and Multi-State Medicaid Databases. Psychiatric-related follow-up outpatient visits within 30 days of discharge were identified from Medicaid claims based on Healthcare Effectiveness Data and Information Set specifications. Kaplan-Meier curves and Cox proportional hazards models were used to describe and analyze time to follow-up visit and to identify patient and hospitalization characteristics associated with follow-up visit. Results: The study sample (N=1,312) had a mean age of 40.5 years and was 57% male. A follow-up outpatient visit was identified among 47% of patients. The proportion of patients with a follow-up visit ranged from 25% in 2005 to 48% in 2010/2011. The Cox proportional hazard model suggests that capitated health plan, attending physician specialty of psychiatry/psychology, and later year of index hospitalization significantly increase the probability of a follow-up visit, while substance-related disorders significantly decrease the probability. Type of antipsychotic received during index hospitalization was not significantly associated with probability of a follow-up visit. Conclusion: While follow-up visit rates have increased over time, this study highlights the ongoing need for improvements in effective linkage to outpatient care for patients hospitalized and treated for schizophrenia, particularly among patients with comorbid substance abuse disorder.
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Welk, Blayne, Kim Chi Tran, Kuan Liu, and Salimah Shariff. "The pattern of urologic care among traumatic spinal cord injured patients." Canadian Urological Association Journal 8, no. 11-12 (November 24, 2014): 805. http://dx.doi.org/10.5489/cuaj.2403.
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Introduction: We assessed the urologic care patterns of traumatic spinal cord injury (TSCI) patients.Methods: This was a retrospective cohort study of adult TSCI patients injured between 2002 and 2012. The primary outcome was urologic consultation. The primary exposure was the year of injury. Measured covariates included lesion level, age, gender, comorbidity burden, and socioeconomic status.Results: We identified 1551 incident TSCI patients who were discharged from a rehabilitation hospital in Ontario between 2002 and 2012. The median follow-up time of this cohort was 5.0 (interquartile range [IQR] 2.9–7.5) years. Within this cohort, 74% were male, and the mean age was 48 (IQR 33-63) years. In total, 66% of patients (1022/1551) were seen by a urologist in a median of 0.7 (IQR 0.2-3.0) years after the SCI. Over the study period, there was no change in the proportion of TSCI patients being assessed by a urologist within 1 year of their initial injury (median 55.1%, p = 0.92 for the trend). An adjusted Cox proportional hazards model demonstrated that TSCI patients who were female (hazard ratio [HR] 0.77, 95% confidence interval [CI] 0.66–0.92) or over 65 years of age (HR 0.70, 95% CI 0.57–0.85) were significantly less likely to be referred to a urologist.Conclusions: Urologists are often not involved in the care of TSCI patients, and this has not changed significantly over the last 10 years. Females and older patients are significantly less likely to be referred to a urologist.
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Steinmetz, Jacob, Karl Bang Christensen, Thomas Lund, Nicolai Lohse, and Lars S. Rasmussen. "Long-term Consequences of Postoperative Cognitive Dysfunction." Anesthesiology 110, no. 3 (March 1, 2009): 548–55. http://dx.doi.org/10.1097/aln.0b013e318195b569.
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Background Postoperative cognitive dysfunction (POCD) is common in elderly patients after noncardiac surgery, but the consequences are unknown. The authors' aim was to determine the effects of POCD on long-term prognosis. Methods This was an observational study of Danish patients enrolled in two multicenter studies of POCD between November 1994 and October 2000. The cohort was followed up from the date of surgery until August 2007. Cognitive function was assessed by a neuropsychological test battery at three time points: before, at 1 week after, and at 3 months after noncardiac surgery. Data on survival, labor market attachment, and social transfer payments were obtained from administrative databases. The Cox proportional hazards regression model was used to compute relative risk estimates for mortality and disability, and the relative prevalence of time on social transfer payments was assessed by Poisson regression. Results A total of 701 patients were followed up for a median of 8.5 yr (interquartile range, 5.3-11.4 yr). POCD at 3 months, but not at 1 week, was associated with increased mortality (hazard ratio, 1.63 [95% confidence interval, 1.11-2.38]; P = 0.01, adjusted for sex, age, and cancer). The risk of leaving the labor market prematurely because of disability or voluntary early retirement was higher among patients with 1-week POCD (hazard ratio, 2.26 [1.24-4.12]; P = 0.01). Patients with POCD at 1 week received social transfer payments for a longer proportion of observation time (prevalence ratio, 1.45 [1.03-2.04]; P = 0.03). Conclusions Cognitive dysfunction after noncardiac surgery was associated with increased mortality, risk of leaving the labor market prematurely, and dependency on social transfer payments.
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Rassenti, Laura Z., Donna S. Neuberg, Michael J. Keating, John G. Gribben, Ian W. Flinn, Kanti R. Rai, John C. Byrd, Neil E. Kay, and Thomas J. Kipps. "CD38 Compared with ZAP-70 or Immmunoglobulin Mutation Status as Predictor of Disease Progression in Chronic Lymphocytic Leukemia." Blood 104, no. 11 (November 16, 2004): 2805. http://dx.doi.org/10.1182/blood.v104.11.2805.2805.
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Abstract We performed immunophenotypic and IgVH mutation analyses on the chronic lymphocytic leukemia (CLL) cells of 307 patients for expression of CD38, ZAP-70, and IgVH mutation status to determine the relative strength of each in predicting the need for early treatment. For this we assessed the time from diagnosis to initial therapy for progressive and/or symptomatic disease. Patients confirmed to have remained untreated were censored for this endpoint. Expression of CD38 was defined as the proportion of CD38-stained CLL cells that had fluorescence intensity above a defined threshold. Similarly, cases were defined as ZAP-70+ when 20% or more of the ZAP-70-stained CLL cells had fluorescence intensity above a defined threshold, as described (NEJM351:893, 2004). CLL cells were classified as expressing mutated IgVH genes if they expressed IgVH with <98% homology with a known germline IgVH gene. The median percentage of cells expressing CD38 in our cohort was 11.5% (range 0.1% to 99.5%). In patients with multiple samples, the CD38 expression level appeared constant over time, with a median S.D. of 0.8%. We defined patient samples that had CD38 expression levels at or below the median as having low expression. There was a significant association between low expression of CD38 and lack of ZAP-70 or expression of a mutated IgVH (p < 0.0001 for each assessment by the Fisher exact test). Median level of CD38 among cases expressing mutated IgVH was 4.0%, compared to 27.4% among cases expressing unmutated IgVH (p < 0.0001 by the Wilcoxon rank sum test). Median level of CD38 among ZAP-70 negative cases was 5.3%, compared to 27.2% among ZAP-70+ cases (p < 0.0001 by the Wilcoxon rank sum test). Patients with low-level expression of CD38 had a median time to initiation of therapy of 8.2 years; whereas, patients with high-level expression of CD38 had a median time to initiation of therapy of 4.0 years (p<0.0001). Although high-level expression of CD38 was associated with a shorter time from diagnosis to initiation of therapy (p < 0.0001 in a Cox proportional hazards regression), the inclusion of IgVH mutation status (p < 0.0001) or expression of ZAP-70 (p < 0.0001) in these models reduced the contribution of CD38 status to a p-value of 0.051 (ZAP-70 model) or 0.052 (mutation status model). Although ZAP-70 expression and mutation status each contributed significantly to the hazard of initiating therapy in a Cox proportional hazards model, high-level expression of CD38 did not add significantly to the model that already addresses ZAP-70 and mutational status, p=0.425. As such, although knowledge of the CD38 expression level can be used as a predictor of the time from diagnosis to the initiation of therapy it provides only marginal value if either the IgVH mutational status or expression of ZAP-70 is known and no value if knowledge of both ZAP-70 expression and IgVH mutational status is available.
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Beal, Shannon H., Steven L. Chen, Philip D. Schneider, and Steve R. Martinez. "An Evaluation of Lymph Node Yield and Lymph Node Ratio in Well-Differentiated Thyroid Carcinoma." American Surgeon 76, no. 1 (January 2010): 28–32. http://dx.doi.org/10.1177/000313481007600107.
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It is unknown whether the number of lymph nodes harvested (lymph node yield, LNY) or the proportion of metastatic lymph nodes resected (metastatic lymph node ratio, MLNR) influence survival in well-differentiated thyroid carcinoma (WDTC). We hypothesized that overall survival in WDTC is influenced by the LNY and MLNR. We used the Surveillance, Epidemiology, and End Results database to identify all patients with primary, nonmetastatic WDTC who underwent thyroidectomy with at least one lymph node removed between 1988 and 2004. Kaplan-Meier survival curves for LNY and MLNR were compared using the log rank test. Multivariate Cox proportional hazards models included tumor and patient-specific factors. WDTC patients that met entry criteria totaled 9926. In the univariate model, LNY and MLNR had a significant impact on survival ( P < 0.001). In multivariate analysis, increasing LNY was associated with poorer survival in all patients ( P = 0.001) and node-negative patients ( P = 0.03), but not for node-positive patients ( P = 0.27). MLNR did not influence survival in node-positive patients ( P = 0.84). Among patients with WDTC treated with thyroidectomy and lymphadenectomy, increasing LNY and MLNR were associated with decreased survival. The decrease in survival associated with increasing LNY, even in node-negative patients, indicates that nodal understaging is inconsequential to WDTC survival.
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Bharat, Chrianna I., Kevin Murray, Edward Cripps, and Melinda R. Hodkiewicz. "Methods for displaying and calibration of Cox proportional hazards models." Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability 232, no. 1 (November 26, 2017): 105–15. http://dx.doi.org/10.1177/1748006x17742779.
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Cox proportional hazards modelling is a widely used technique for determining relationships between observed data and the risk of asset failure when model performance is satisfactory. Cox proportional hazards models possess good explanatory power and are used by asset managers to gain insight into factors influencing asset life. However, validation of Cox proportional hazards models is not straightforward and is seldom considered in the maintenance literature. A comprehensive validation process is a necessary foundation to build trust in the failure models that underpin remaining useful life prediction. This article describes data splitting, model discrimination, misspecification and fit methods necessary to build trust in the ability of a Cox proportional hazards model to predict failures on out-of-sample assets. Specifically, we consider (1) Prognostic Index comparison for training and test sets, (2) Kaplan–Meier curves for different risk bands, (3) hazard ratios across different risk bands and (4) calibration of predictions using cross-validation. A Cox proportional hazards model on an industry data set of water pipe assets is used for illustrative purposes. Furthermore, because we are dealing with a non-statistical managerial audience, we demonstrate how graphical techniques, such as forest plots and nomograms, can be used to present prediction results in an easy to interpret way.
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Chidambaram, Mala, Joanne M. Bargman, Robert R. Quinn, Peter C. Austin, Janet E. Hux, and Andreas Laupacis. "Patient and Physician Predictors of Peritoneal Dialysis Technique Failure: A Population Based, Retrospective Cohort Study." Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis 31, no. 5 (September 2011): 565–73. http://dx.doi.org/10.3747/pdi.2010.00096.
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BackgroundThe use of peritoneal dialysis (PD) has been declining over the past decade in Canada, and high technique failure rates have been implicated. Studies have examined clinical risk factors for PD technique failure, but few studies have addressed sociodemographic factors driving technique failure. There are no studies examining the effect of physician factors on technique failure.MethodsWe conducted a retrospective cohort study using Ontario healthcare databases from 1 April 1995 to 31 March 2005 to examine the effects of patient sociodemographic and physician characteristics on PD technique failure. The primary outcome was time to technique failure. Secondary outcomes included the proportion of patients experiencing technique failure during the first year and the proportion of patients experiencing death during the study period. A competing risks analysis was applied to the Cox proportional hazards model to determine the predictors of technique failure, death, and kidney transplantation.ResultsIn 5162 incident PD patients, the probability of technique success and patient survival at 5 years was 58.2% and 46.9% respectively. Of patients failing PD, 43.5% failed during the first year of treatment. Statistically significant predictors of technique failure included increasing age [hazard ratio (HR) 1.02], diabetes mellitus (HR 1.32), lower neighborhood education level (HR 2.93), and receiving transient (≤ 3 months) hemodialysis before starting PD (HR 1.24). Predictors of patient death included increasing age (HR 1.05), diabetes mellitus (HR 1.44), coronary artery disease (HR 1.26), congestive heart failure (HR 1.58), and late referral to the nephrologist (HR 1.27). Distance from treating dialysis center and residing in a rural area did not impact the risk of technique failure or death. Male physician gender increased the risk of technique failure (HR 1.31). Increased PD patient volume decreased the risk of technique failure (HR 0.98). None of the physician factors were predictors of patient death.ConclusionThese findings support the need for implementing strategies to reduce technique failure, which could include increasing educational resources for patients initiating PD, aggressive risk factor modification in patients with multiple comorbidities, and increasing physician awareness regarding the detrimental outcomes associated with late referral and late PD start.
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Fukuoka, Masahiro, Yi-Long Wu, Sumitra Thongprasert, Patrapim Sunpaweravong, Swan-Swan Leong, Virote Sriuranpong, Tsu-Yi Chao, et al. "Biomarker Analyses and Final Overall Survival Results From a Phase III, Randomized, Open-Label, First-Line Study of Gefitinib Versus Carboplatin/Paclitaxel in Clinically Selected Patients With Advanced Non–Small-Cell Lung Cancer in Asia (IPASS)." Journal of Clinical Oncology 29, no. 21 (July 20, 2011): 2866–74. http://dx.doi.org/10.1200/jco.2010.33.4235.
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Purpose The results of the Iressa Pan-Asia Study (IPASS), which compared gefitinib and carboplatin/paclitaxel in previously untreated never-smokers and light ex-smokers with advanced pulmonary adenocarcinoma were published previously. This report presents overall survival (OS) and efficacy according to epidermal growth factor receptor (EGFR) biomarker status. Patients and Methods In all, 1,217 patients were randomly assigned. Biomarkers analyzed were EGFR mutation (amplification mutation refractory system; 437 patients evaluable), EGFR gene copy number (fluorescent in situ hybridization; 406 patients evaluable), and EGFR protein expression (immunohistochemistry; 365 patients evaluable). OS analysis was performed at 78% maturity. A Cox proportional hazards model was used to assess biomarker status by randomly assigned treatment interactions for progression-free survival (PFS) and OS. Results OS (954 deaths) was similar for gefitinib and carboplatin/paclitaxel with no significant difference between treatments overall (hazard ratio [HR], 0.90; 95% CI, 0.79 to 1.02; P = .109) or in EGFR mutation–positive (HR, 1.00; 95% CI, 0.76 to 1.33; P = .990) or EGFR mutation–negative (HR, 1.18; 95% CI, 0.86 to 1.63; P = .309; treatment by EGFR mutation interaction P = .480) subgroups. A high proportion (64.3%) of EGFR mutation–positive patients randomly assigned to carboplatin/paclitaxel received subsequent EGFR tyrosine kinase inhibitors. PFS was significantly longer with gefitinib for patients whose tumors had both high EGFR gene copy number and EGFR mutation (HR, 0.48; 95% CI, 0.34 to 0.67) but significantly shorter when high EGFR gene copy number was not accompanied by EGFR mutation (HR, 3.85; 95% CI, 2.09 to 7.09). Conclusion EGFR mutations are the strongest predictive biomarker for PFS and tumor response to first-line gefitinib versus carboplatin/paclitaxel. The predictive value of EGFR gene copy number was driven by coexisting EGFR mutation (post hoc analysis). Treatment-related differences observed for PFS in the EGFR mutation–positive subgroup were not apparent for OS. OS results were likely confounded by the high proportion of patients crossing over to the alternative treatment.
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Mauer, Murielle E. L., Martin J. B. Taphoorn, Andrew Bottomley, Corneel Coens, Fabio Efficace, Marc Sanson, Alba A. Brandes, et al. "Prognostic Value of Health-Related Quality-of-Life Data in Predicting Survival in Patients With Anaplastic Oligodendrogliomas, From a Phase III EORTC Brain Cancer Group Study." Journal of Clinical Oncology 25, no. 36 (December 20, 2007): 5731–37. http://dx.doi.org/10.1200/jco.2007.11.1476.
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Purpose This is one of a few studies that have explored the value of baseline symptoms and health-related quality of life (HRQOL) in predicting survival in patients with brain cancer. Patients and Methods Baseline HRQOL scores (from the European Organisation for Research and Treatment of Cancer [EORTC] Quality of Life Questionnaire C30 and the EORTC Brain Cancer Module) were examined in 247 patients with anaplastic oligodendrogliomas to determine the relationship with overall survival by using Cox proportional hazards regression models. Refined techniques as the bootstrap resampling procedure and the computation of C indexes and R2 coefficients were used to explore the stability of the models as well as better assess the potential benefit of using HRQOL to predict survival in clinical practice and research. Results Classical analysis controlled for major clinical prognostic factors selected emotional functioning (P = .0016), communication deficit (P = .0261), future uncertainty (P = .0481), and weakness of legs (P = .0001) as statistically significant prognostic factors of survival. However, several issues question the validity of these findings and no single model was found to be preferable over all others. C indexes, which estimate the probability of a model to correctly predict which patient among a randomly chosen pair of patients will survive longer, and R2 coefficients, which measure the proportion of variability explained by the model, did not exhibit major improvement when adding selected or all HRQOL scores to clinical factors. Conclusion While classical techniques lead to positive results, more refined analyses suggest that baseline HRQOL scores add relatively little to clinical factors to predict survival. These results may have implications for future use of HRQOL as a prognostic factor for patients with cancer.
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O'Neill, Terence J. "The Inverse Proportional Hazards Model." Statistics & Probability Letters 12, no. 2 (August 1991): 125–29. http://dx.doi.org/10.1016/0167-7152(91)90055-v.
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Kumar, Dhananjay, and Bengt Klefsjö. "Proportional hazards model: a review." Reliability Engineering & System Safety 44, no. 2 (January 1994): 177–88. http://dx.doi.org/10.1016/0951-8320(94)90010-8.
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Liu, David, Philip Abbosh, Daniel Keliher, Brendan Reardon, Kent William Mouw, Amaro Taylor-Weiner, Stephanie Anne Mullane, et al. "Subclonal mutational heterogeneity and survival in cisplatin-resistant muscle-invasive bladder cancer." Journal of Clinical Oncology 35, no. 15_suppl (May 20, 2017): 4512. http://dx.doi.org/10.1200/jco.2017.35.15_suppl.4512.
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4512 Background: Biomarkers of survival and resistance in chemotherapy-resistant muscle-invasive bladder cancer (MIBC) are not well-characterized, but may inform management in this setting. Methods: Matched pre- and post-neoadjuvant cisplatin-based chemotherapy (NAC) tumor samples were obtained from 30 MIBC patients with gross residual disease (≥ pT2) at cystectomy, followed by whole exome sequencing of these “trios” (pre- and post-NAC tumor with matched germline samples). Phylogenetic analysis of matched tumor samples was performed to identify subclones, their associated mutations, and the corresponding enrichment in post-treatment tumors. Intratumoral heterogeneity was assessed by the proportion of mutations that were subclonal; the number of inferred subclones; and associated with overall survival using a Cox Proportional Hazards model. Results: Increased proportion of subclonal mutations in post-treatment tumors was associated with worse overall survival (HRR 1.86 [95% CI 1.12-3.06], p = 0.02), whereas pre-treatment proportion of subclonal mutations was only borderline statistically significant (HRR 1.48 [95% CI 0.99-2.20], p = 0.052). The total number of inferred tumor subclones in pre- or post-treatment tumor (or both) was associated with overall survival (HRR 1.60 [95% CI 1.05-2.43], p = 0.03), interpreted as a 60% increase in death rate per additional inferred subclone. While no single gene was statistically significantly enriched for new alterations in the post-chemotherapy resistant samples, we observed new post-treatment amplifications in cell-cycle genes ( E2F3, c-JUN), biallelic events in cell-cycle regulators ( FBXW7), and amplification of immune checkpoint genes ( PDL1/2). Conclusions: These results suggest that intratumoral heterogeneity (particularly post-therapy) predicts survival in a chemotherapy-resistant cohort. Further, alterations in cell cycle regulation may contribute to the mechanism of chemotherapy resistance. Finally, we observe evidence of immune checkpoint gene amplification post-treatment, suggesting that testing immune checkpoint blockade during NAC or, in high risk patients, following NAC may be warranted.
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Silva, Maíra Domingues Bernardes, Raquel de Vasconcellos Carvalhaes de Oliveira, Davi da Silveira Barroso Alves, and Enirtes Caetano Prates Melo. "The effect of risk at birth on breastfeeding duration and exclusivity: A cohort study at a Brazilian referral center for high-risk neonates and infants." PLOS ONE 16, no. 8 (August 6, 2021): e0255190. http://dx.doi.org/10.1371/journal.pone.0255190.
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Background and aim Both breastfeeding and the use of human milk are strategies that provide better conformation to health throughout an individual’s life and bring countless short- and long- term benefits, which are well established in the scientific literature. For at-risk newborns (NBs), these strategies are crucial interventions to enable neonatal survival with better quality of life due to the distinctive and complex composition of human milk, which serves as personalized food-medicine-protection. However, there is limited knowledge about breastfeeding practices in high-risk NBs. The aim was to estimate the duration of EBF and to investigate the effect of risk at birth on EBF discontinuity in the first six months of life’. Methods This cohort study included 1,003 NBs from a high-risk referral center, followed up from birth to the sixth month of life, between 2017 and 2018. Correspondence and cluster analysis was used to identify neonatal risk clusters as the main exposure. The object of interest was the time until EBF discontinuity. The Kaplan-Meier methods and the Cox proportional hazards model were used to estimate the hazard ratio and 95% confidence intervals. Results The prevalence and median duration of EBF decreased proportionally in the three groups. The multiple model revealed a gradient in EBF discontinuity, which was 40% higher in risk group 1 and 111% higher in risk group 2 compared to healthy full-term NBs. Additionally, EBF during hospitalization predicted a longer median duration of this practice for high-risk NBs. Conclusion This study confirms a high proportion of high-risk NBs who have EBF discontinued before six months of life. The risk of EBF discontinuity is higher in risk groups, with a gradual effect even when adjusted by several factors. Effective interventions are needed to promote, protect, and support breastfeeding in different profiles of risk-at-birth groups.
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Moon, Piljun, and Kang Mo Jeong. "Significance Tests in Cox Proportional Hazard Model for Survival Times of Complex Survey Data." Korean Data Analysis Society 19, no. 6 (December 31, 2017): 2881–90. http://dx.doi.org/10.37727/jkdas.2017.19.6.2881.
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Chang, Tara I.-Hsin, Sai Liu, Medha Airy, Jingbo Niu, Mintu P. Turakhia, Jennifer E. Flythe, Maria E. Montez-Rath, and Wolfgang C. Winkelmayer. "Blood Pressure and Incident Atrial Fibrillation in Older Patients Initiating Hemodialysis." Clinical Journal of the American Society of Nephrology 14, no. 7 (June 7, 2019): 1029–38. http://dx.doi.org/10.2215/cjn.13511118.
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Background and objectivesWe examined the association of predialysis systolic and diastolic BP and intradialytic hypotension with incident atrial fibrillation in older patients initiating hemodialysis.Design, setting, participants, & measurementsWe used the US Renal Data System linked to the records of a large dialysis provider to identify patients aged ≥67 years initiating hemodialysis between January 2006 and October 2011. We examined quarterly average predialysis systolic BP, diastolic BP, and proportion of sessions with intradialytic hypotension (i.e., nadir systolic BP <90 mm Hg). We applied an extended Cox model to compute adjusted hazard ratios (HRs) of each exposure with incident atrial fibrillation.ResultsAmong 17,003 patients, 3785 developed atrial fibrillation. When comparing predialysis systolic BP to a fixed reference of 140 mm Hg, lower predialysis systolic BP was associated with a higher hazard of atrial fibrillation, whereas higher systolic BP was associated with a lower hazard of atrial fibrillation. When comparing across a range of systolic BP for two hypothetical patients with similar measured covariates, the association varied by mean systolic BP: at systolic BP 190 mm Hg, each 10 mm Hg lower systolic BP was associated with lower atrial fibrillation hazard (HR, 0.94; 95% confidence interval, 0.90 to 1.00), whereas at systolic BP 140 mm Hg, a 10 mm Hg lower systolic BP was associated with a higher atrial fibrillation hazard (HR, 1.12; 95% confidence interval, 1.10 to 1.14). Lower diastolic BP was associated with higher atrial fibrillation hazards. Intradialytic hypotension was weakly associated with atrial fibrillation.ConclusionsIn this observational study of older patients initiating hemodialysis, lower predialysis systolic BP and diastolic BP were associated with higher incidence of atrial fibrillation.
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Knighton, James, Kelly Hondula, Cielo Sharkus, Christian Guzman, and Rebecca Elliott. "Flood risk behaviors of United States riverine metropolitan areas are driven by local hydrology and shaped by race." Proceedings of the National Academy of Sciences 118, no. 13 (March 15, 2021): e2016839118. http://dx.doi.org/10.1073/pnas.2016839118.
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Flooding risk results from complex interactions between hydrological hazards (e.g., riverine inundation during periods of heavy rainfall), exposure, vulnerability (e.g., the potential for structural damage or loss of life), and resilience (how well we recover, learn from, and adapt to past floods). Building on recent coupled conceptualizations of these complex interactions, we characterize human–flood interactions (collective memory and risk-enduring attitude) at a more comprehensive scale than has been attempted to date across 50 US metropolitan statistical areas with a sociohydrologic (SH) model calibrated with accessible local data (historical records of annual peak streamflow, flood insurance loss claims, active insurance policy records, and population density). A cluster analysis on calibrated SH model parameter sets for metropolitan areas identified two dominant behaviors: 1) “risk-enduring” cities with lower flooding defenses and longer memory of past flood loss events and 2) “risk-averse” cities with higher flooding defenses and reduced memory of past flooding. These divergent behaviors correlated with differences in local stream flashiness indices (i.e., the frequency and rapidity of daily changes in streamflow), maximum dam heights, and the proportion of White to non-White residents in US metropolitan areas. Risk-averse cities tended to exist within regions characterized by flashier streamflow conditions, larger dams, and larger proportions of White residents. Our research supports the development of SH models in urban metropolitan areas and the design of risk management strategies that consider both demographically heterogeneous populations, changing flood defenses, and temporal changes in community risk perceptions and tolerance.
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Zhu, Xiaodong, and Lingfei Yu. "Screening Contract Excitation Models Involving Closed-Loop Supply Chains Under Asymmetric Information Games: A Case Study with New Energy Vehicle Power Battery." Applied Sciences 9, no. 1 (January 3, 2019): 146. http://dx.doi.org/10.3390/app9010146.
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In closed-loop supply chain systems for power battery remanufacturing, recycling and dismantling tasks will be relegated to third-party recyclers. This has significant disadvantages, inasmuch as the asymmetric exchange of information regarding the level of recycling capacity and effort after signing a contract fiscal risks to the manufacturers. The purpose of this paper is to study the “adverse selection” of recyclers and “moral hazards” hidden in their purported effort levels, based on Information Screening Models in the principal-agent theory. Our information screening model for revenue sharing will be presented, and subsequently verified using numerical simulation to demonstrate the impact of the screening contract on the expected returns of both parties. Our results show that the sharing coefficient of the remanufacturing revenue for low-capability recyclers is distorted downwards, and only truthful reporting can retain profits. High-capacity recyclers will obtain additional information while retaining profit. At the same time, as the proportion of high-capacity recyclers in the market increases, the expected return of the entrusting party increases. One critical area where this will impact the Chinese economy is in the area of new energy vehicles. We investigate a case study of our approach in new energy vehicles, which are being used to reduced CO 2 emissions, but have environmentally hazardous batteries that must be recycled safely and economically.
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Wiefarn, Stefan, Christian Heumann, Anja Rettelbach, and Karel Kostev. "Risk of Nonfatal Stroke in Type 2 Diabetes Mellitus Patients: A Retrospective Comparison Between Disease Management Programs and Standard Care." Journal of Diabetes Science and Technology 11, no. 4 (February 9, 2017): 808–13. http://dx.doi.org/10.1177/1932296817691304.
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Objective: The present retrospective study examines the influence of disease management programs on nonfatal stroke in type 2 diabetes mellitus (T2DM) patients in Germany. Methods: The evaluation is based on retrospective patient data from the Disease Analyzer (IMS Health). The analysis included 169 414 T2DM patients aged 40 years and older with an initial prescription of antihyperglycemic therapy between January 2004 and December 2014. A total of 86 713 patients participated in a disease management program (DMP) for T2DM and 82 701 patients received standard care. The main outcome measure of this study was nonfatal stroke. Kaplan-Meier curves of DMP and SC patients were compared using log rank test. The Cox proportional hazards model was used to provide an adjusted estimate of the DMP effect. Results: It is apparent from the baseline characteristics that the general health of patients receiving standard care was poorer than that of patients participating in a DMP. The baseline HbA1c value was 7.6% in the DMP group and 7.8% in the SC group. Furthermore, the SC group had a higher proportion of preexisting conditions, such as coronary heart disease (CHD), peripheral arterial occlusive disease (pAOD), and renal insufficiency. The proportion of patients who received insulin in first year therapy was higher in the SC group. Time to event analysis showed that DMP was associated with a delayed occurrence of stroke, because stroke occurred an average of 350 days later in DMP patients than in patients receiving SC (DMP: 1.216 days, RV: 866 days). The Cox model with covariable adjustment confirmed the significant association of DMPs with nonfatal stroke in patients with type 2 diabetes mellitus (HR 0.71; 95% CI: 0.69-0.74). Conclusion: The present study indicates that DMPs are positively associated with stroke. The possible reasons for this must be verified in further studies.
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Kropko, Jonathan, and Jeffrey J. Harden. "Beyond the Hazard Ratio: Generating Expected Durations from the Cox Proportional Hazards Model." British Journal of Political Science 50, no. 1 (November 27, 2017): 303–20. http://dx.doi.org/10.1017/s000712341700045x.
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The Cox proportional hazards model is a commonly used method for duration analysis in political science. Typical quantities of interest used to communicate results come from the hazard function (for example, hazard ratios or percentage changes in the hazard rate). These quantities are substantively vague, difficult for many audiences to understand and incongruent with researchers’ substantive focus on duration. We propose methods for computing expected durations and marginal changes in duration for a specified change in a covariate from the Cox model. These duration-based quantities closely match researchers’ theoretical interests and are easily understood by most readers. We demonstrate the substantive improvements in interpretation of Cox model results afforded by the methods with reanalyses of articles from three subfields of political science.
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Kuk, Anthony Y. C. "A Non‐Proportional Hazards Model with Hazard Ratio Functions Free from Covariate Values." International Statistical Review 88, no. 3 (March 22, 2020): 715–27. http://dx.doi.org/10.1111/insr.12364.
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Rubio, Francisco J., Laurent Remontet, Nicholas P. Jewell, and Aurélien Belot. "On a general structure for hazard-based regression models: An application to population-based cancer research." Statistical Methods in Medical Research 28, no. 8 (August 2018): 2404–17. http://dx.doi.org/10.1177/0962280218782293.
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The proportional hazards model represents the most commonly assumed hazard structure when analysing time to event data using regression models. We study a general hazard structure which contains, as particular cases, proportional hazards, accelerated hazards, and accelerated failure time structures, as well as combinations of these. We propose an approach to apply these different hazard structures, based on a flexible parametric distribution (exponentiated Weibull) for the baseline hazard. This distribution allows us to cover the basic hazard shapes of interest in practice: constant, bathtub, increasing, decreasing, and unimodal. In an extensive simulation study, we evaluate our approach in the context of excess hazard modelling, which is the main quantity of interest in descriptive cancer epidemiology. This study exhibits good inferential properties of the proposed model, as well as good performance when using the Akaike Information Criterion for selecting the hazard structure. An application on lung cancer data illustrates the usefulness of the proposed model.
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Honma, Rio, Ichiro Kinoshita, Eiji Miyoshi, Utano Tomaru, Yoshihiro Matsuno, Yasushi Shimizu, Satoshi Takeuchi, Kichizo Kaga, Naoyuki Taniguchi, and Hirotoshi Akita. "Prognostic significance of α1,6-fucosyltransferase (α1,6-FT) in non-small cell lung cancers (NSCLCs)." Journal of Clinical Oncology 31, no. 15_suppl (May 20, 2013): 7550. http://dx.doi.org/10.1200/jco.2013.31.15_suppl.7550.
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7550 Background: Lung cancer is one of the leading causes of cancer death throughout the world. A more sophisticated understanding of the pathogenesis and biology of NSCLCs could provide useful information for predicting clinical outcome and individualizing treatment. α1,6-FT is the only one enzyme responsible for the core α1,6-fucosylation of N-glycans of glycoproteins, including EGF receptor, TGF-β1 receptor, and integrin α3β1. Methods: α1,6-FT expression was studied by immunohistochemistry in a cohort of 129 surgically resected NSCLCs, classified categorically based on the proportion of positively stained cancer cells (high, > 20%; or low, < 20%), and analyzed statistically in relation to various characteristics, including histology, survival and prognosis. Results: High and low expression of α1,6-FT was found in 67 and 62 of 129 NSCLCs, respectively. Multivariate logistic regression analysis revealed a significant association between high α1,6-FT expression and non-squamous cell carcinoma (mostly adenocarcinoma), as compared with squamous cell carcinomas (odds ratio, 3.51; p = 0.008). Patients with tumors having high α1,6-FT expression had significantly shorter survival time than patients with tumors having low expression in potentially curatively resected NSCLCs (p = 0.03) and adenocarcinomas (p = 0.009), as well as in pStage I NSCLCs (p = 0.03) by the log-rank test. Surprisingly, in pStage I adenocarcinomas, 12 of 23 patients with tumors having high α1,6-FT expression died of lung cancer, although none of 15 patients with tumors having low expression died of lung cancer. High α1,6-FT expression was a significant and independent unfavorable prognostic factor in potentially curatively resected NSCLCs (hazard ratio, 1.81; p = 0.047) and adenocarcinomas (hazard ratio 2.39; p = 0.006) and in pStage I NSCLCs (hazard ratio 2.55; p = 0.03) by Cox’s proportional hazards model analysis. Conclusions: These results suggest that α1,6-FT may play a pivotal role for the biological characteristics of NSCLCs. α1,6-FT expression is associated with histology of NSCLCs, and may be a new prognostic marker for overall NSCLCs and adenocarcinomas.
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Longbrake, Erin E., Anne H. Cross, and Amber Salter. "Efficacy and tolerability of oral versus injectable disease-modifying therapies for multiple sclerosis in clinical practice." Multiple Sclerosis Journal - Experimental, Translational and Clinical 2 (January 2016): 205521731667786. http://dx.doi.org/10.1177/2055217316677868.
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Background The advent of oral disease-modifying therapies fundamentally changed the treatment of multiple sclerosis. Nevertheless, impressions of their relative efficacy and tolerability are primarily founded on expert opinion. Objective The purpose of this study was to determine whether oral disease-modifying therapies were better tolerated and/or more effective for controlling multiple sclerosis compared to injectable therapies in clinical practice. Methods Single-center, retrospective cohort study. 480 patients initiated oral (fingolimod, teriflunomide, or dimethyl fumarate) or injectable therapy between March 2013–March 2015 and follow-up data was collected for 5–31 months. Outcomes included on-drug multiple sclerosis activity and drug discontinuation. Cox proportional hazards models were used to control for baseline differences and sensitivity analyses using propensity-weighted matching were performed. Results A higher proportion of teriflunomide-treated patients experienced multiple sclerosis activity compared to those treated with injectable therapies ( p = 0.0053) in the adjusted model. Breakthrough multiple sclerosis was equally prevalent among fingolimod and dimethyl fumarate-treated compared to injectable therapy-treated patients. Of patients initiating a disease-modifying therapy, 32–46% discontinued or switched treatments during the study. After controlling for baseline differences, discontinuation rates were comparable across treatment groups. Conclusions In this cohort, oral and injectable disease-modifying therapies were equally well tolerated, but teriflunomide appeared less effective for controlling multiple sclerosis activity than injectable therapies. Further study is needed.
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Lee, Sewon, Andrew C. Povey, Martin J. Seed, and Martie van Tongeren. "Insufficient respiratory hazard identification in the safety data sheets for cleaning and disinfection products used in healthcare organisations across England and Wales." Occupational and Environmental Medicine 78, no. 4 (February 9, 2021): 293–95. http://dx.doi.org/10.1136/oemed-2020-106881.
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BackgroundExposure to cleaning and disinfection products has been associated with respiratory disorders such as asthma in cleaning and healthcare workers. Safety data sheets (SDSs) provide information on hazardous chemicals that are present in products to help users with risk assessment and implement appropriate control measures. However, they have potential limitations in identifying respiratory hazards due to a lack of regulatory test methods for respiratory sensitisation and irritation of chemicals.MethodsSDSs were first used to identify chemicals on the database as respiratory sensitisers and irritants. A quantitative structure–activity relationship (QSAR) model and an asthmagen list established by the Association of Occupational and Environmental Clinics (AOEC) were used to identify potential respiratory sensitisers and irritants (by the AOEC list only) in the cleaning and disinfection products.ResultsFrom a total of 459 cleaning and disinfection products used in healthcare organisations across England and Wales, 35 respiratory sensitisers not labelled as such on the SDS were identified by QSAR or AOEC. Only 2% of cleaning and disinfection products contained at least one respiratory sensitiser as identified by their SDSs; this was increased to 37.7% of products when the QSAR or the AOEC list was used.ConclusionsA significantly higher proportion of cleaning products contain respiratory hazardous chemicals, particularly respiratory sensitisers than would be expected from the information provided by SDSs alone. Cleaners and healthcare workers may, therefore, be insufficiently protected.