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Stainsby, Richard, Karen Peers, Colin Mitchell, Christian Poette, Konstantin Mikityuk, and Joe Somers. "Gas Cooled Fast Reactor Research and Development in the European Union." Science and Technology of Nuclear Installations 2009 (2009): 1–7. http://dx.doi.org/10.1155/2009/238624.
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Gas-cooled fast reactor (GFR) research is directed towards fulfilling the ambitious goals of Generation IV (Gen IV), that is, to develop a safe, sustainable, reliable, proliferation-resistant and economic nuclear energy system. The research is directed towards developing the GFR as an economic electricity generator, with good safety and sustainability characteristics. Fast reactors maximise the usefulness of uranium resources by breeding plutonium and can contribute to minimising both the quantity and radiotoxicity nuclear waste by actinide transmutation in a closed fuel cycle. Transmutation is particularly effective in the GFR core owing to its inherently hard neutron spectrum. Further, GFR is suitable for hydrogen production and process heat applications through its high core outlet temperature. As such GFR can inherit the non-electricity applications that will be developed for thermal high temperature reactors in a sustainable manner. The Euratom organisation provides a route by which researchers in all European states, and other non-European affiliates, can contribute to the Gen IV GFR system. This paper summarises the achievements of Euratom's research into the GFR system, starting with the 5th Framework programme (FP5) GCFR project in 2000, through FP6 (2005 to 2009) and looking ahead to the proposed activities within the 7th Framework Programme (FP7).
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Twomey, PJ, and DR Pledger. "Estimated GFR." Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 42, no. 3 (2005): 237–48. http://dx.doi.org/10.1258/0004563053857888.
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Drukker, W. "Measuring GFR." International Journal of Artificial Organs 10, no. 2 (1987): 129–30. http://dx.doi.org/10.1177/039139888701000213.
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Rossing, P., K. Rossing, P. Gaede, O. Pedersen, and H. H. Parving. "Estimated GFR." Journal of the American Society of Nephrology 17, no. 8 (2006): 2077–85. http://dx.doi.org/10.1681/01.asn.0000926840.41580.dc.
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Stevens, Lesley A., and Andrew S. Levey. "Measured GFR as a Confirmatory Test for Estimated GFR." Journal of the American Society of Nephrology 20, no. 11 (2009): 2305–13. http://dx.doi.org/10.1681/asn.2009020171.
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Allison, Susan J. "Estimating GFR and GFR decline in patients with T2DM." Nature Reviews Nephrology 9, no. 5 (2013): 246. http://dx.doi.org/10.1038/nrneph.2013.50.
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Nimbolkar, Janardan, Shubha Chogle, Lata Bhandarkar, Aruna Poojary, and Ritu Chandel. "Cystatin GFR better marker than creatinine GFR for accurate prediction of renal dysfunction in diabetic patients: A tertiary care centre study." International Journal of Clinical Biochemistry and Research 9, no. 1 (2022): 53–58. http://dx.doi.org/10.18231/j.ijcbr.2022.010.
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Diabetic and hypertensive patients gradually gets decreased glomerular function. Creatinine starts rising and exhibits decreased kidney function when more than 50% of glomerular function is lost. Cystatin C, a parameter which accesses kidney function accurately predicts GFR. GFR is calculated by measuring Cystatin C and Creatinine. Groups were normal patients, diabetics patients, Comparison of changes of pre and post treatment GFR by Creatinine and Cystatin. Total 57 patient studied 1) Cystatin C GFR is lower than creatinine GFR in 20 normal patients with P value with paired t test is 0.0032 hence prompts early renal evaluation whereas creatinine GFR overestimates renal function. 2) cystatin C GFR in 37 patients with kidney dysfunction and diabetes is less than Creatine GFR with p-value < 0.05 suggests more accurate prediction for renal injury. 3) Cystatin GFR is affected by age and gender 4) Change in Pre and Post treatment of 9 patients with creatinine GFR and cystatin GFR with p-value = 0.47657 > 0.05 but these patients high Creatinine levels on admission which gets normalised with remarkable rise in GFR whereas Cystatin C levels gets marginally decrease suggests renal recovery ongoing. Clearly exhibits Creatinine GFR is overestimates renal function. Patients with normal GFR by Creatinine having raised Cystatin C levels prompts early renal evaluation. Cystatin C is accurately estimating, less affected by variables and predicting severity of renal dysfunction. Thus, Cystatin C GFR better diagnostic and sensitive maker than creatinine GFR for accurate prediction of renal dysfunction in Diabetic patients.
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Schmitz, R., S. Reder, J. Höchel, and H. Hartmann. "Beziehungen zwischen den Werten des endogenen Serumkreatinins und der glomerulären Filtrationsrate (GFR) bei nierengesunden sowie-kranken Hunden und Katzen." Tierärztliche Praxis Ausgabe K: Kleintiere / Heimtiere 36, no. 02 (2008): 111–18. http://dx.doi.org/10.1055/s-0038-1622668.
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Zusammenfassung: Zielstellung: Gleichzeitige Bestimmung des endogenen Serumkreatinins (eSk) und der glomerulären Filtrationsrate (GFR) Hunden und Katzen und retrospektive Untersuchung der diagnostischen Qualität (Sensitivität, Spezifität) des eSk zur Feststellung einer renalen Eubzw. Malfunktion. Material und Methoden: In die Studie gingen 493 Hunde (Alter: 7,0 [3,0–9,0] Jahre) und 278 Katzen (Alter: 10,0 [6,5–12,0] Jahre) aus vier europäischen Ländern ein. Die Hunde/ Katzen gehörten 34/12 verschiedenen Rassen an oder waren Mischlinge. Das veterinärmedizinische Fachpersonal vor Ort führte bei den Tieren einen renalen Funktionstest mit modifizierter Bestimmung der Plasma-Clearance von exogenem Kreatinin zur quantitativen Bestimmung der GFR durch. Das Kreatinin im Serum wurde mittels Jaffé-Methode ermittelt. Die optimalen Grenzwerte für das eSk mit maximaler diagnostischer Sensitivität und Spezifität zur Erkennung einer renalen Eu-/Malfunktion wurden mithilfe der Receiver-OperatingCharacteristic-(ROC-)Analytik bestimmt. Ergebnisse: Von den Hunden erwiesen sich 238 Tiere (48,3%) als nierengesund (GFR ≥ 70% der Norm) und 255 Tiere (51,7%) als unterschiedlich intensiv nierenkrank (GFR < 70% der Norm). Bei den Katzen waren 104 Tiere (37,4%) nierengesund und 174 Tiere (62,6%) nierenkrank. Zur Unterscheidung von nierengesund/-krank ergaben sich für Hunde/Katzen optimale Grenzwerte des eSk von 98/141 μmol/l. Die diagnostische Qualität dieser Grenzwerte war mit der Sensitivität bzw. Spezifität von 77 bzw. 82% (Hunde) und 82 bzw. 73% (Katzen) unzureichend niedrig gegeben. Wiesen die nierenkranken Hunde/Katzen nur noch eine GFR von ≤ 30% der Norm auf, betrugen die optimalen Grenzwerte des eSk 153/274 μmol/l. Ihre diagnostische Qualität war mit der durchschnittlichen Sensitivität bzw. Spezifität von 100 bzw. 89% bei Hunden gut und von 79 bzw. 96% bei Katzen zufrieden stellend gegeben. Klinische Relevanz: Infolge niedriger Werte der diagnostischen Sensitivität bzw. Spezifität eignet sich der eSk-Gehalt bei Hunden und Katzen zur Frühdiagnostik einer renalen Malfunktion nur wenig oder gar nicht. Eine verlässliche Frühdiagnostik erfordert einen renalen Funktionstest mit quantitativer GFR-Bestimmung. Erst nierenkranke Tiere mit einer GFR von nur noch ≤ 30% der Norm können anhand der eSk-Werte diagnostisch gut (Hund) oder zufrieden stellend (Katze) erfasst werden.
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Koshkin, Vadim S., Pedro C. Barata, Haris Zahoor, et al. "Cisplatin-based neoadjuvant chemotherapy (NAC) in bladder cancer patients (Pts) with borderline renal function: Implications for clinical practice." Journal of Clinical Oncology 35, no. 6_suppl (2017): 390. http://dx.doi.org/10.1200/jco.2017.35.6_suppl.390.
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390 Background: Cisplatin-based NAC prior to cystectomy is a standard of care in muscle-invasive bladder cancer (MIBC). There are limited data for pts with borderline glomerular filtration rate (GFR) who get cisplatin-based NAC. Methods: A retrospective review of pts who received cisplatin-based NAC at Cleveland Clinic (2005-2016) was done. Pts with pre-NAC GFR of 40-59 mL/min by either CG or MDRD formula (low GFR group; n = 17) were compared to pts with GFR ≥ 60 (nl GFR group; n = 74) for treatment-related toxicities and outcomes, such as pathologic complete (pCR, pT0N0) and partial response (pPR, < pT2N0), overall survival (OS) and recurrence-free survival (RFS). Comparisons were made using Fisher’s exact, Wilcoxon, or log-rank tests. Results: Pts with low GFR were older (median age 69 vs 64, p = .02) with worse PS (44% vs 20% ECOG > 0, p < .05). Gender, race, hydronephrosis rates and TURBT features (stage, grade, LVI, CIS) did not differ. For NAC, 64 pts got Gem/Cis (49 normal GFR, 15 low GFR), 23 got MVAC (22 normal GFR, 1 low GFR), 4 got other. Low GFR pts were less likely to get MVAC (6% vs 30%, p = .08) and more likely to get split-dose cisplatin (38% vs 18%, p = .10) and have NAC modified (delayed, dose reduced or stopped) (69% vs 36%, p = .02). 4/17 pts (24%) with low GFR and 9/73 (12%) with normal GFR did not complete all planned NAC cycles (p = .26). Hematologic toxicity caused most dose delays but renal toxicity was the most common cause of NAC stoppage (4/9 normal GFR, 3/4 low GFR). NAC cycles completed (median 3 / group) and G-CSF use (31/61 normal GFR, 3/9 low GFR) were comparable. No difference was noted in time to cystectomy (mean 107 days for normal vs 103 days for low GFR from NAC start), surgical complications, length of stay, and either post-NAC or post-cystectomy GFR decline from baseline. Combined pathologic response (pCR/pPR) was higher in normal GFR pts (50% vs 18%, p = .02). OS and RFS at 2 years were 89% and 79% for normal GFR and 78% and 58% for low GFR. Conclusions: Low GFR pts were older with worse PS, had more NAC modifications, lower pCR/pPR and trend for shorter OS & RFS, but most completed planned NAC cycles. For very carefully selected pts with GFR 40-59, cisplatin-based NAC is a treatment option.
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Krawiec, Donald R., A. Robert Twardock, Robert R. Badertscher, Gregory B. Daniel, and Steven J. Dugan. "Use of 99mTc diethylenetriaminepentaacetic acid for assessment of renal function in dogs with suspected renal disease." Journal of the American Veterinary Medical Association 192, no. 8 (1988): 1077–80. https://doi.org/10.2460/javma.1988.192.08.1077.
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Summary The effectiveness of technetium 99m-labeled diethylenetriaminepentaacetic acid (99mTc dtpa) to assess renal function in 13 dogs with suspected renal disease was evaluated. Glomerular filtration rates (actual gfr) were determined on the basis of endogenous creatinine clearance. Predicted gfr were determined by using 99mTc dtpa within 72 hours after the determination of creatinine clearance. The percentage of an iv administered dose of 99mTc dtpa in the kidneys (percentage dose) was determined. Two equations were used to calculate predicted gfr, which were derived from previously reported linear regression analysis of inulin (In) and creatinine (Cr) gfr vs percentage dose 99mTc dtpa in dog kidneys. The correlations of actual gfr vs predicted gfr (In) and actual gfr vs predicted gfr (Cr) were both r = 0.92. The dogs’ mean actual gfr was 1.73 ± 1.35 ml/min/kg. Their mean predicted gfr (In) and predicted gfr (Cr) were 1.92 ± 1.42 ml/min/kg and 1.85 ± 1.27 ml/min/kg, respectively. Therefore, 99mTc dtpa can be used with high accuracy as an agent to predict gfr in dogs with suspected renal disease. The procedure for determining gfr by use of nuclear medicine was rapid and noninvasive and appeared to induce little stress in the animals evaluated.
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Fagerberg, B., C. Fagerlund, and J. Hulthe. "Resistin and GFR." Kidney International 70, no. 7 (2006): 1371. http://dx.doi.org/10.1038/sj.ki.5001583.
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eo. "GFR-Grenze gesenkt." MMW - Fortschritte der Medizin 157, no. 14 (2015): 27. http://dx.doi.org/10.1007/s15006-015-3403-9.
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Lee, Chang Hwa. "Estimation of GFR." Korean Journal of Medicine 83, no. 4 (2012): 455. http://dx.doi.org/10.3904/kjm.2012.83.4.455.
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Schwartz, George J. "Does kL/PCr estimate GFR, or does GFR determine k?" Pediatric Nephrology 6, no. 6 (1992): 512–15. http://dx.doi.org/10.1007/bf00866487.
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Toto, R. D., K. A. Kirk, J. Coresh, et al. "Evaluation of serum creatinine for estimating glomerular filtration rate in African Americans with hypertensive nephrosclerosis: results from the African-American Study of Kidney Disease and Hypertension (AASK) Pilot Study." Journal of the American Society of Nephrology 8, no. 2 (1997): 279–87. http://dx.doi.org/10.1681/asn.v82279.
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Measurement of GFR is considered the standard for estimating renal function. However, standardized accurate GFR methodology is expensive and cumbersome; therefore, estimates of GFR based on serum creatinine concentration have been employed. The purpose of the study presented here was to assess the accuracy and precision of using serum creatinine measurements to estimate GFR in the screen cohort of The African-American Study of Kidney Disease and Hypertension (AASK) Pilot Study. GFR was estimated by four methods: 100/serum creatinine, Cockcroft-Gault equation, creatinine clearance from 24-h urine collection, and a new regression equation derived from the pilot study data. These methods were compared with renal clearance of 125I-iothalamate GFR (GFR1) in 193 hypertensive (diastolic blood pressure > or = 95 mm Hg) African-American screen (142 men, 51 women). A second GFR (GFR2) was performed in 98 screen who were eligible (GFR1 25-70 mL/min per 1.73 m2) for the pilot study. Accuracy was assessed by the difference of 125I-iothalamate GFR-estimated GFR (delta GFR), and precision was estimated from the combined root mean squared error (CRMSE) and the coefficient of determination (r2). The results for accuracy (+/- SD) and precision were as follows: (1) 100/Scr, delta GFR = -0.76 +/- 16.5, CRMSE = 16.5, r2 = 0.69; (2) Cockcroft-Gault, delta GFR = 9.56 +/- 14.9, CRMSE = 17.7, r2 = 0.66; 3) 24-h creatinine clearance, delta GFR = 0.79 +/- 20.7, CRMSE = 20.7, r2 = 0.49; 4) New equation delta GFR = -0.08 +/- 12.8, CRMSE 12.7, r2 = 0.75. In comparison, a second GFR (GFR2, N = 98) had delta GFR = 1.36 +/- 8.48, CRMSE 8.6, r2 = 0.75. Estimates based on 100/SCr and the new equation were the most precise. It was concluded that GFR estimated by serum creatinine is superior to outpatient 24-h urine creatinine clearance in this population. Serum creatinine values can be used to provide a reasonably accurate estimate of GFR in hypertensive African Americans.
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Koshkin, Vadim S., Pedro C. Barata, Haris Zahoor, et al. "Cisplatin-based neoadjuvant chemotherapy (NAC) for muscle-invasive bladder cancer (MIBC) in patients (pts) with impaired renal function." Journal of Clinical Oncology 36, no. 6_suppl (2018): 446. http://dx.doi.org/10.1200/jco.2018.36.6_suppl.446.
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446 Background: Cisplatin-based NAC followed by radical cystectomy is the standard of care in MIBC but many pts are cisplatin-unfit. Data in pts with low glomerular filtration rate (GFR) who receive cisplatin-based NAC is limited. Methods: A retrospective analysis of pts who received cisplatin-based NAC at Cleveland Clinic (2005-2016) was conducted. Pts with pre-NAC GFR < 60 ml/min by either CG or MDRD formula (low GFR; N = 30) were compared to pts with GFR ≥60 (normal GFR; N = 94) in terms of NAC tolerability and outcomes including pathologic complete (pCR, pT0N0) and partial response (pPR, < pT2N0). A secondary analysis compared 3 groups of pts: GFR < 50ml/min (N = 10), GFR 50-59 ml/min (N = 20), and GFR ≥60 (N = 94). Results: Low GFR pts were older (median age 71 vs 65, p < 0.001) and had higher rates of hydronephrosis (33% vs 15%, p = 0.03). ECOG PS, other demographic and TURBT features (stage, LVI, CIS) did not differ significantly. Low GFR pts were more likely to receive gemcitabine/cisplatin (83% vs 71%, p = 0.04) and get split-dose cisplatin (38% vs 16%, p = 0.02). Split-dose cisplatin use in low GFR pts did not impact NAC tolerability or outcomes. NAC cycles completed (median 3 per group) were comparable, and most low GFR pts (70%) completed intended NAC regimen. Low GFR pts were more likely to have early NAC discontinuation (30% vs 13%, p = 0.03) and NAC modification (delay, dose reduction, discontinuation) (66% vs 40%, p = 0.02). No differences were seen in cystectomy completion rate (93% per group), time to cystectomy, length of stay, surgical complications, and GFR change from baseline. Combined pCR/pPR was higher in normal GFR group (54% vs 25%, p = 0.01). Among pts with very low GFR ( < 50 ml/min), 60% completed intended NAC regimen and 70% had NAC modification. Rates of pCR and pPR were low: 0% and 12%, respectively. Conclusions: Low GFR pts were older, had more NAC discontinuations/modifications and lower pCR/pPR rate, but most completed planned NAC cycles. Relative to normal GFR pts, low GFR pts were not prevented or delayed in getting cystectomy, and had comparable impact of NAC on GFR. For carefully selected pts with GFR < 60 ml/min, cisplatin-based NAC is a treatment option, consistent with prior data.
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G, Hong, Dan L, and Yunhe L. "Comparison of clinical value of dynamic contrast-enhanced MRI and SPECT renal dynamic imaging of GFR measurement in the evaluation of renal function in renal transplantation." Discussion of Clinical Cases 6, no. 2 (2019): 7. http://dx.doi.org/10.5430/dcc.v6n2p7.
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Objective: To compare the clinical value of dynamic contrast-enhanced MRI (DCE-MRI) and single-photon emission computed tomography (SPECT) renal dynamic imaging in the measurement of glomerular filtration rate (GFR) in the evaluation of renal function in renal transplantation.Methods: A total of 70 recipients who underwent renal transplantation in Baogang Hospital of Inner Mongolia from April of 2015 to April of 2018 were selected as research objects. GFR was measured in renal transplant recipients by use of DCE-MRI and SPECT (GFR-MRI and GFR-SPECT respectively), and was compared with creatinine clearance rate (Ccr). The safety of contrast media was evaluated in DCE-MRI detection.Results: The bias of GFR-MRI against Ccr value was higher than that of GFR-SPECT against Ccr value, with 30% and 50% accuracy of GFR-MRI higher than that of GFR-SPECT, and the difference was statistically significant (p < .05). Pearson correlation analysis showed that GFR-MRI and GFR-SPECT values were positively correlated to Ccr (p < .05), and the correlation coefficient of GFR-MRI and Ccr was higher than that of GFR-SPECT and Ccr, with the difference statistically significant (p < .05). By Bland-Altman analysis, 95% confidence interval of GFR-SPECT was 95.49 ml/(min·1.73 m2), and 95% confidence interval of GFR-MRI was 62.35 ml/(min·1.73m2), which was much narrower. Only 2 cases of patients developed mild rash among 70 cases of patients, and recovered spontaneously without any treatment.Conclusions: Compared with SPECT, the bias of GFR measured by DCE-MRI against Ccr is much greater. However, DCE-MRI has a higher accuracy, correlation and consistency in comparison with Ccr, and it has a narrower confidence interval. DCE-MRI can more accurately evaluate renal function in renal transplantation by measuring GFR, and it has a high safety.
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van Londen, Marco, Brigitte M. Aarts, Jan-Stephan F. Sanders, et al. "Tubular maximum phosphate reabsorption capacity in living kidney donors is independently associated with one-year recipient GFR." American Journal of Physiology-Renal Physiology 314, no. 2 (2018): F196—F202. http://dx.doi.org/10.1152/ajprenal.00287.2017.
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The donor glomerular filtration rate (GFR) measured before kidney donation is a strong determinant of recipient graft outcome. No tubular function markers have been identified that can similarly be used in donors to predict recipient outcomes. In the present study we investigated whether the pre-donation tubular maximum reabsorption capacity of phosphate (TmP-GFR), which may be considered a functional tubular marker in healthy kidney donors, is associated with recipient GFR at 1 yr after transplantation, a key determinant of long-term outcome. We calculated the pre-donation TmP-GFR from serum and 24-h urine phosphate and creatinine levels in 165 kidney donors, and recipient 125I-iothalamate GFR and eGFR (CKD-EPI) at 12 mo after transplantation. Kidney donors were 51 ± 10 yr old, 47% were men, and mean GFR was 118 ± 26 ml/min. The donor TmP-GFR was associated with recipient GFR 12 mo after transplantation (GFR 6.0 ml/min lower per 1 mg/dl decrement of TmP-GFR), which persisted after multivariable adjustment for donor age, sex, pre-donation GFR, and blood pressure and other potential confounders. Results were highly similar when eGFR at 12 mo was taken as the outcome. Tubular damage markers kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin were low and not associated with recipient GFR. A lower donor TmP-GFR before donation, which may be considered to represent a functional measure of tubular phosphate reabsorption capacity, is independently associated with a lower recipient GFR 1 yr after transplantation. These data are the first to link donor tubular phosphate reabsorption with recipient GFR post-transplantation.
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Lee, Seung Eun, Juhwan Yoo, Kyoung-Ah Kim, Kyungdo Han, and Han Seok Choi. "Hip Fracture Risk According to Diabetic Kidney Disease Phenotype in a Korean Population." Endocrinology and Metabolism 37, no. 1 (2022): 148–58. http://dx.doi.org/10.3803/enm.2021.1315.
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Background: Diabetic kidney disease (DKD) is associated with an elevated risk of fractures. However, little is known about the association between proteinuric or non-proteinuric DKD and the risk of hip fracture. Thus, we investigated the incidence of hip fractures among Korean adults with type 2 diabetes mellitus (T2DM) stratified by DKD phenotype.Methods: In this retrospective cohort study using the Korean National Health Insurance Service database, patients with T2DM who received at least one general health checkup between 2009 and 2012 were followed until the date of hip fracture, death, or December 31, 2018. We classified the DKD phenotype by proteinuria and estimated glomerular filtration rate (eGFR), as follows: no DKD (PU−GFR−), proteinuric DKD with normal eGFR (PU+GFR−), non-proteinuric DKD with reduced eGFR (PU−GFR+), and proteinuric DKD with reduced eGFR (PU+GFR+)Results: The cumulative incidence of hip fractures was highest in the PU+GFR+ group, followed by the PU−GFR+ group and the PU+GFR− group. After adjustment for confounding factors, the hazard ratio (HR) for hip fracture was still highest in the PU+GFR+ group. However, the PU+GFR− group had a higher HR for hip fracture than the PU−GFR+ group (PU+GFR+ : HR, 1.69; 95% confidence interval [CI], 1.57 to 1.81; PU+GFR− : HR, 1.37; 95% CI, 1.30 to 1.46; PU−GFR+ : HR, 1.20; 95% CI, 1.16 to 1.24 using the PU−GFR− group as the reference category).Conclusion: The present study demonstrated that DKD was significantly associated with a higher risk of hip fracture, with proteinuria as a major determinant.
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Tran, Adrienne, Janice Loh, Lingyun Ji, et al. "Baseline GFR and cisplatin-induced renal toxicity in urothelial cancer patients." Journal of Clinical Oncology 34, no. 2_suppl (2016): 380. http://dx.doi.org/10.1200/jco.2016.34.2_suppl.380.
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380 Background: Cisplatin eligibility for clinical trials has been defined as calculated GFR > 60 mL/min due to risk of nephrotoxicity in patients (pts) with renal impairment. For urothelial cancer (UCa), substitution of cisplatin compromises outcomes. We evaluated change in GFR in pts treated with cisplatin despite baseline GFR < 60 to determine risk of nephrotoxicity. Methods: 150 USC pts were identified who received systemic therapy for UCa from 2009 to 2014. Creatinine and weight values closest to treatment start and finish were used for calculation of GFR using the Cockcroft-Gault formula. Wilcoxon rank-sum tests and analyses of variance (ANOVA) were used to compare GFR percent change by age ( < 75 vs > 75 years), pre-treatment GFR ( < 60 vs > 60), therapy setting (neoadjuvant, adjuvant, or metastatic), primary disease site, and comorbidities (diabetes, hypertension, hyperlipidemia). Log-rank tests and Cox regression models were used to examine the association between overall survival (OS) and age or GFR. Results: 114 received cisplatin-based therapy at least once; 26 in the neo-adjuvant setting, 27 adjuvant, and 61 for metastatic disease. GFR could be calculated pre- and post-treatment for 81 pts; lowest GFR in pt receiving cisplatin was 25.5 mL/min. Median GFR change was -1.6% (range: -50% ~ 49%) for pts with pre-treatment GFR < 60 compared to -10.9% (range -72%, 135%) for pts with pre-treatment GFR > 60 (p = 0.17). Treatment setting (neo-adjuvant, adjuvant, or metastatic) had significant association with GFR change (p = 0.027). Median (range) of GFR change for the neo-adjuvant setting, adjuvant setting and metastatic setting was 4.6% (95% CI -32%, 90%), -5.8% (95% CI-39%, 20%), -11.9% (95% CI -72%, 135%), respectively. Age, primary disease site, diabetes, hypertension and hyperlipidemia were not associated with GFR change. Univariate analysis showed an association between GFR > 60 at stop of treatment with worse OS (p = 0.087) in metastatic pts. Conclusions: Our data support the hypothesis that UCa pts with GFR < 60 do not experience a greater decline in renal function after cisplatin treatment compared to patients with GFR > 60. If validated, this may extend the option of cisplatin-based therapy to previously ineligible pts.
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Donadio, Carlo. "Serum and urinary markers of early impairment of GFR in chronic kidney disease patients: diagnostic accuracy of urinary β-trace protein". American Journal of Physiology-Renal Physiology 299, № 6 (2010): F1407—F1423. http://dx.doi.org/10.1152/ajprenal.00507.2009.
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The screening for chronic kidney diseases (CKD) patients with impaired GFR needs the measurement of serum creatinine (SCr) or cystatin C (SCys). GFR can also be predicted from SCr or SCys with different formulas. The aim of this study, performed in a group of CKD patients with different levels of GFR, was to evaluate the possibility to select the patients with a GFR <90 ml·min−1·1.73 m−2by means of serum levels and urinary excretion of different low-molecular-weight proteins (LMWP), cystatin C (Cys), β2-microglobulin (β2M), retinol-binding protein (RBP), β-trace protein (BTP), and derived prediction equations for GFR. In the 295 CKD patients (137 women), at all stages of GFR impairment a very high correlation was found between GFR (99mTc-DTPA) and serum Cr, Cys, β2M, and BTP. All these serum markers showed a similar accuracy as indicators of different GFR impairments. RBP had the lowest correlation with GFR and was also significantly less accurate. The different prediction formulas derived from gender, anthropometric data and SCr or S-LMWP had a diagnostic accuracy similar to that of serum Cr, Cys, β2M, and BTP. Urinary albumin was inadequate as an indicator of any level of GFR impairment. Urinary excretion of Cys and β2M increased significantly only in patients with a GFR <30 ml·min−1·1.73 m−2, while urinary BTP increased already at GFR <90 ml·min−1·1.73 m−2. In this selected group of CKD patients, the positive predictive value of urinary BTP for a GFR <90 ml·min−1·1.73 m−2was 85%, indicating that, in CKD patients, a urine-based test can predict a slight GFR impairment.
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Nankivell, Brian J., Jeremy R. Chapman, and Richard D. M. Allen. "Predicting glomerular filtration rate after simultaneous pancreas and kidney transplantation." Clinical Transplantation 9, no. 2 (1995): 129–34. http://dx.doi.org/10.1111/j.1399-0012.1995.tb00311.x.
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Impairment of glomerular filtration rate (GFR) after simultaneous pancreas and kidney (SPK) transplantation is an important marker of chronic renal rejection and recurrence of diabetic glomerulopathy. The use of unmodified serum creatinine to estimate GFR, however, is limited by variations in muscle mass. In this study, predictive factors for long‐term GFR were evaluated in consecutive SPK recipients (n=33) using a Tc99m DTPA GFR reference method between 90 days and 6 years. after transplantation (n=136 measurements). Substantial variability between serum creatinine and isotopic GFR after SPK (R2=0.30) highlighted the inaccuracy of an unmodified serum creatinine in the evaluation. of GFR. Factors which predicted GFR apart from serum creatinine included age, sex, height and body weight. A detailed formula was derived for accurate estimation of GFR (ml/min)=(71.4 (♂) or 50.4 (♀)] + 5520/ creatinine (μmol/l) + 0.27×body weight (kg) ‐0.50×age (yr) ‐0.29×height (cm). This formula was more accurate in estimation of GFR in SPK recipients than six published predictive methods which were derived from chronic renal failure patients using creatinine clearance. All of these methods overestimated GFR at lower levels of renal function. Most correlated poorly with Tc99m DTPA GFR and contained a generalized systematic overestimation of GFR which ranged from 4.7 to 8.4 ml/min (p<0.05). A simplified version for rapid calculation was also derived as GFR (ml/min)=[25 (♂) or 5 (♀)] + 5000/creatinine (μmol/l). These specific formulae, presented in this study, represent an improvement over published methods for estimation of GFR in SPK, and may be used for long‐term monitoring of renal dysfunction in SPK recipients.
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Abdallah, Nour, Tarik Benidir, Nicholas Heller, et al. "Accuracy of fully automated, AI-generated models compared with validated clinical model to predict post-operative glomerular filtration rate after renal surgery." Journal of Clinical Oncology 41, no. 6_suppl (2023): 693. http://dx.doi.org/10.1200/jco.2023.41.6_suppl.693.
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693 Background: The American Urologic Association (AUA) recommends estimation of the postoperative glomerular filtration rate (GFR) in patients with a renal mass to help decide between partial nephrectomy (PN) or radical nephrectomy (RN). If postoperative GFR<45 mL/min/1.73m2, a PN should be prioritized. Most existing methods to predict postoperative GFR are rarely implemented in the clinical setting due to complexity. Previously validated models based on clinical equations or kidney volumes from hand-segmented or semi-automated segmentations are quite accurate but have seen limited uptake in clinical practice. We hypothesize that we could develop an artificial intelligence (AI)-GFR prediction that would be calculated automatically on a preoperative computed tomography (CT) scan and predict a postoperative GFR as accurately as a validated clinical model. Methods: 300 patients undergoing PN or RN for renal tumor from the 2021Kidney and Kidney Tumor Segmentation Challenge(KiTS21) were analyzed. We excluded 7 patients having bilateral tumors. Preoperative GFR was the closest recorded value preoperatively and postoperative GFR≥90 days postoperatively. Split-renal-function (SRF) was determined in a fully automated way from preoperative imaging and our previously developed deep learning segmentation model. We programmed the algorithm to estimate postoperative GFR as 1.24×preoperative GFR×contralateral SRF for RN; and as 89% of the preoperative GFR for PN. We compared AI-predicted GFR to a validated clinical model (GFR=35+preoperative GFR(x0.65)-18(if radical nephrectomy)-age(x0.25)+3(if tumor size >7 cm)-2 (if diabetes)). We compared the AI and clinical model estimations of GFR to the measured postoperative GFR using correlation coefficients (R) and compared the ability of AI models to predict a postoperative GFR<45 using logistic regression and AUCs. Results: In 293 patients, the median age was 60 years ((IQR) 51-68), 40.6% were female, and 62.1% had PN. The median tumor size was 4.2 (2.6-6.1), and 91.8% of the tumors were malignant, of which 35.1% were high-grade, 25.6% were high-stage, and 21.8% had necrosis. The median R.E.N.A.L. nephrometry score was 8 (7-9). When comparing measured postoperative GFR, the correlation coefficients were 0.75 and 0.77 for the AI model and clinical models, respectively. For the prediction of a postoperative GFR< 45 ml/min/1.73m2, the AI and clinical models performed similarly (AUC of 0.89 and 0.9, respectively). Conclusions: Our study demonstrates the feasibility of a fully automated prediction of postoperative GFR based on CT imaging and baseline GFR with comparable predictive accuracy to existing validated clinical prediction models. These AI-generated predictions can be implemented for decision-making, with no clinical details, clinician time, or measurements needed.
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Tøndel, Camilla, Cathrin Salvador, Karl Ove Hufthammer, et al. "FP771IOHEXOL CLEARANCE IN CHILDREN WITH LOW GFR: COMPARISON OF 24 HOURS SINGLE-POINT GFR AND MULTIPLE-POINT GFR." Nephrology Dialysis Transplantation 33, suppl_1 (2018): i305—i306. http://dx.doi.org/10.1093/ndt/gfy104.fp771.
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Begum, Hosne Ara, Mahbub Ur Rahman, Samira Sharmin, Jesmin Ferdous, and Jamiul Hossain. "Measurement of Glomerular Filtration Rate (GFR) in an Ectopic Pelvic Kidney by Dual Head Gamma Camera." Bangladesh Journal of Nuclear Medicine 20, no. 2 (2018): 114. http://dx.doi.org/10.3329/bjnm.v20i2.37394.
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<p><strong><em>Background</em></strong><em>:</em><strong> </strong>DTPA renogram is an accepted method to measure glomerular filtration rate (GFR) of the kidneys. The function of an ectopic kidney varies on the basis of its size, shape, position and rotation. This may lead to variation in tissue attenuation and error in computed GFR and differential renal function (DRF) of each kidney. The objectives of this study was to assess the changes in the GFR measurement of an ectopic kidney in a dual head gamma camera using anterior and posterior imaging process and its influence on quantification of total GFR.</p><p><strong><em>Patients and Method:</em></strong><strong> </strong>A Total<strong> </strong>20 patients having one ectopic pelvic kidney and other normal positioning kidney were enrolled in the study. DTPA renogram images were acquired on a dual head gamma camera (Symbia T2) in anterior and posterior views simultaneously. Both anterior and posterior images data were used separately to compute the GFR. Three sets of total GFR of both kidneys were calculated separately. In set I, total GFR (ant) is equal to sum of both kidneys GFR in anterior imaging process, in set II total GFR (post) is equal to sum of both kidneys GFR in posterior imaging process and in set III total GFR (ectopic .ant + normal. post) is equal to sum of the GFR of normal kidney on posterior image and the GFR of ectopic kidney on anterior image. These three sets of total GFRs were compared with the patient’s eGFR measured by Cockcroft Gault formula.</p><p><strong><em>Result:</em></strong> Mean age of the patient was 36.9 ± 14.6 years (range 18-70 years). Mean total GFR (ant) was 89.2±11.6 ml/min, total GFR (post) was 82.9±13.4 ml/min and total GFR (ectopic .ant + normal.post) was 102.5±15.9 ml/min. Mean eGFR is 101.93±24.9ml/min. When these three sets of DTPA assisted GFR compare with eGFR the Pearson’s correlation coefficient <em>r=</em> 0.45, 0.55 (P&lt;0.05) for GFR (ant) and GFR (post) respectively whereas, in case of GFR (ectopic .ant + normal.post) correlation coefficient <em>r=</em> 0.8 (P&lt;0.01).</p><p><strong><em>Conclusion:</em></strong> The GFR of ectopic kidney as calculated from the anterior data was significantly higher in comparison to the GFR calculated from the posterior data.</p><p>Bangladesh J. Nuclear Med. 20(2): 115-118, July 2017</p>
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Levey, Andrew S., Silvia M. Titan, Neil R. Powe, Josef Coresh, and Lesley A. Inker. "Kidney Disease, Race, and GFR Estimation." Clinical Journal of the American Society of Nephrology 15, no. 8 (2020): 1203–12. http://dx.doi.org/10.2215/cjn.12791019.
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Assessment of GFR is central to clinical practice, research, and public health. Current Kidney Disease Improving Global Outcomes guidelines recommend measurement of serum creatinine to estimate GFR as the initial step in GFR evaluation. Serum creatinine is influenced by creatinine metabolism as well as GFR; hence, all equations to estimate GFR from serum creatinine include surrogates for muscle mass, such as age, sex, race, height, or weight. The guideline-recommended equation in adults (the 2009 Chronic Kidney Disease Epidemiology Collaboration creatinine equation) includes a term for race (specified as black versus nonblack), which improves the accuracy of GFR estimation by accounting for differences in non-GFR determinants of serum creatinine by race in the study populations used to develop the equation. In that study, blacks had a 16% higher average measured GFR compared with nonblacks with the same age, sex, and serum creatinine. The reasons for this difference are only partly understood, and the use of race in GFR estimation has limitations. Some have proposed eliminating the race coefficient, but this would induce a systematic underestimation of measured GFR in blacks, with potential unintended consequences at the individual and population levels. We propose a more cautious approach that maintains and improves accuracy of GFR estimates and avoids disadvantaging any racial group. We suggest full disclosure of use of race in GFR estimation, accommodation of those who decline to identify their race, and shared decision making between health care providers and patients. We also suggest mindful use of cystatin C as a confirmatory test as well as clearance measurements. It would be preferable to avoid specification of race in GFR estimation if there was a superior, evidence-based substitute. The goal of future research should be to develop more accurate methods for GFR estimation that do not require use of race or other demographic characteristics.
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Jahan, F., MNU Chowdhury, T. Mahbub, et al. "Assessing glomerular filtration rate in healthy adult potential kidney donors in Bangladesh: A comparison of various prediction equations with measured glomerular filtration rate by diethylentriamine pentaacetic acid renogram." Bangladesh Medical Research Council Bulletin 39, no. 2 (2014): 74–79. http://dx.doi.org/10.3329/bmrcb.v39i2.19646.
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To ensure that potential kidney donors in Bangladesh have no renal impairment, it is extremely important to have accurate methods for evaluating the glomerular filtration rate (GFR). We evaluated the performance of serum creatinine based GFR in healthy adult potential kidney donors in Bangladesh to compare GFR determined by DTPA with that determined by various prediction equations. In this study GFR in 61 healthy adult potential kidney donors were measured with 99mTc-diethylenetriamine penta-acetic acid (DTPA) renogram. We also estimated GFR using a four variable equation modification of diet in renal disease (MDRD), Cockcroft-Gault creatinine clearance (CG CrCl), Cockcroft-Gault glomerular filtration rate (CG-GFR). The mean age of study population was 34.31±9.46 years and out of them 65.6% was male. In this study mean mGFR was 85.4±14.8. Correlation of estimated GFR calculated by CG-CrCl, CG-GFR and MDRD were done with measured GFR DTPA using quartile. Kappa values were also estimated which was found to be 0.104 for (p=0.151), 0.336 for (p=0.001) and 0.125 for (p=0.091) respectively. This indicates there is no association between estimated GFR calculated by CG-CrCl, CG-GFR, MDRD with measured GFR DTPA. These results show poor performance of these equations in evaluation of renal function among healthy population and also raise question regarding validity of these equations for assessment of renal function in chronic kidney disease in our population. DOI: http://dx.doi.org/10.3329/bmrcb.v39i2.19646 Bangladesh Med Res Counc Bull 2013; 39: 74-79
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Steele, T. H., and L. Challoner-Hue. "Glomerular response to verapamil by isolated spontaneously hypertensive rat kidney." American Journal of Physiology-Renal Physiology 248, no. 5 (1985): F668—F673. http://dx.doi.org/10.1152/ajprenal.1985.248.5.f668.
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We investigated the possibility that altered cell calcium regulation may affect function of isolated Kyoto spontaneously hypertensive rat (SHR) kidneys as compared with kidneys from Wistar-Kyoto control (WKY) rats. The kidneys were perfused at 120 and 160 mmHg. At 120 mmHg, SHR glomerular filtration rate (GFR) was 0.24 +/- 0.04 compared with WKY GFR of 0.70 +/- 0.10 ml/min (P = 0.001). At 160 mmHg, SHR GFR was 0.48 +/- 0.05 compared with WKY GFR of 1.09 +/- 0.05 ml/min (P less than 0.001). At 120 mmHg, addition of norepinephrine increased renal vascular resistance (RVR) by 50% and decreased SHR GFR by 27% and WKY GFR by 57% (P = 0.04). At 160 mmHg, norepinephrine elicited similar changes. Addition of verapamil, 5-10 microM, in the presence of norepinephrine returned RVR to 100-110% of control. With verapamil at 120 mmHg, SHR GFR increased to 0.84 +/- 0.23 ml/min, a value 3.5 times that of control (P = 0.03). In contrast, WKY GFR in the presence of norepinephrine and verapamil was 0.97 +/- 0.07 ml/min, unchanged from control (P = 0.07). At 160 mmHg, norepinephrine and verapamil also failed to increase WKY GFR above control (P = 0.4) but increased SHR GFR to 52% above control (P = 0.03). Isolated SHR kidneys exhibited exaggerated GFR responses to verapamil but not to norepinephrine. Abnormal cell calcium regulation may underlie the marked decrease in GFR when SHR kidneys are perfused acutely at normotensive perfusion pressures.
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Miller, Scott T., Russell E. Ware, Abdullah Kutlar, et al. "Serum Cystatin-C Levels in Infants with Sickle Cell Anemia: Baseline Data from the BABY HUG Trial." Blood 112, no. 11 (2008): 4791. http://dx.doi.org/10.1182/blood.v112.11.4791.4791.
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Abstract Background: BABY HUG is an NHLBI/NICHD sponsored double-blind placebo-controlled trial (NCT00006400) testing the hypothesis that hydroxyurea therapy (HU), if started early in life, will prevent or postpone organ damage to the spleen and kidney in infants with sickle cell anemia (SCA). All BABY HUG subjects at entry have GFR measured by 99mTc-DTPA radioisotope clearance (DTPA) and estimated using the Schwartz formula, a calculation based on serum creatinine (Cr) and height of the patient (GFR = κ (height)/Cr); κ=0.55 for children age &gt;1 to 13 yr or 0.45 for term infants to age 1 yr. Measurement of GFR in infants is problematic due to difficulties in obtaining urine specimens and venous access. While Cr is a well-established marker for GFR it is not independent of body mass and may be secreted by renal tubules, leading to an overestimate of GFR. Cystatin C (CysC) is a cysteine protease inhibitor produced by all human nucleated cells and freely filtered by the kidney. Serum levels are not affected by muscle mass or gender and stable from age 18 mo to 50 yr, with higher levels in newborns reflecting a lower GFR. CysC offers a more practical and perhaps more accurate measure of GFR than Cr, especially in children with SCA. Normal non-SCA values are 0.5 to 1.4 mg/L. Formulas are published to translate serum levels of CysC to GFR as conventionally reported. Our aim was to determine usual and mean CysC levels in infants with SCA and compare CysC to DTPA and Cr-based assessments of GFR. Methods: Sera obtained and frozen during the eligibility screening phase of BABY HUG were used to determine CysC levels by particle enhanced immune nephelometry. Results: A total of 152 sera from infants age 9–17 mo (mean 13.5) were available. CysC levels ranged from 0.532 to 1.369 mg/L (mean 0.92; median 0.907), approximating the normal range. CysC was strongly and inversely associated with GFR estimated by DTPA (R2=0.086; p=0.001). CysC was also significantly associated with age (inversely, p=0.02), Schwartz GFR (using κ=0.55) (inversely, p=0.007) and Cr (p=0.01), but not with Hb, HbF or WBC count. GFR determined using two CysC-based formulae and the Schwartz formula were compared to GFR by DTPA. GFR Formula GFR* R-square P-value Regression slope *(mean ± SD in ml/min/1.73m2);99mTc-DTPA GFR=123.67±33.72 ml/min/1.73 m2 GFR in non-SS infants age 1–1.5 yr by 51Cr-EDTA clearance: 91.5±17.8 ml/min/1.73 m2 (Piepsz A et al. Eur J Nucl Med Imag2006;33:1477) Schwartz, κ=0.55 191.11±57.85 0.062 0.036 0.141 Schwartz, κ=0.45 154.80 ± 54.06 0.052 0.0123 0.172 CysC (1) 84.45±19.11 0.18 0.0026 0.149 CysC (2) 102.78±25.09 0.16 0.0029 0.196 GFR determined using CysC-based formula 2: GFR = antilog {1.92 + [1.123 × log (1/CysC)]} gave mean values closest to DTPA and similar to published estimates of GFR in non-SCA infants. The Schwartz formula overestimated GFR, especially when the higher κ was used. While correlations are low due to high GFR variability, the four GFR determinations all have a significant association with DTPA. However, because the slopes of the regression lines are not close to 1 (line of equality), measurement agreement with DTPA is poor. Conclusion: The Schwartz formula overestimated GFR in BABY HUG subjects. CysC-based GFR formulae underestimate GFR compared to concurrent DTPA values, but results are similar to published norms. Reports of hyperfiltration, based on creatinine-based determination of GFR, may be exaggerated. The impact of hydroxyurea therapy on CysC levels, if any, will be apparent at completion of the trial in late 2009.
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Lieberthal, W., A. M. Sheridan, and C. R. Valeri. "Protective effect of atrial natriuretic factor and mannitol following renal ischemia." American Journal of Physiology-Renal Physiology 258, no. 5 (1990): F1266—F1272. http://dx.doi.org/10.1152/ajprenal.1990.258.5.f1266.
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We have examined the effect of atrial natriuretic factor (ANF) administered with and without mannitol on renal function following ischemic injury in both the isolated erythrocyte-perfused rat kidney and in the rat in vivo. ANF, administered alone after 25 min ischemia in the isolated kidney, reversed postischemic vasoconstriction but did not improve glomerular filtration rate (GFR). Mannitol alone had no effect on either renal vascular resistance or GFR. However, in isolated kidneys treated with the combination of both ANF and mannitol following reflow, GFR (0.65 +/- 0.04 ml.min-1.g-1) was markedly improved compared with GFR in the untreated ischemia group (0.20 +/- 0.04 ml.min-1.g-1) and was not different from GFR in the nonischemic controls (0.68 +/- 0.05 ml.min-1.g-1). Comparable results were obtained in studies performed in vivo. In rats subjected to 45 min ischemia, GFR (0.15 +/- 0.05 ml/min) was reduced compared with the GFR in sham-operated animals (0.95 +/- 0.07 ml/min). ANF or mannitol administered alone following ischemia and reflow did not improve GFR compared with the untreated ischemic group. However, in rats subjected to ischemia and treated with a combination of ANF and mannitol postreflow, GFR (0.69 +/- 0.10 ml/min) was 4.6-fold higher than GFR in the untreated ischemic group. Thus the combination of ANF and mannitol appear to act synergistically to improve GFR following ischemic injury.
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Staziaki, Pedro V., Harshna V. Vadvala, Vanessa Fiorini Furtado, Dania Daye, Ronald S. Arellano, and Raul N. Uppot. "Early trends and predictors of renal function following computed tomography-guided percutaneous cryoablation of a renal mass in patients with and without prior renal impairment." Radiologia Brasileira 53, no. 3 (2020): 141–47. http://dx.doi.org/10.1590/0100-3984.2019.0098.
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Abstract Objective: To assess trends and predictors of the glomerular filtration rate (GFR) after renal mass cryoablation in patients with and without history of renal impairment. Materials and Methods: This was a retrospective study of 39 patients who underwent computed tomography-guided percutaneous cryoablation of a renal mass, divided into two groups: those with prior renal impairment (PRI+); and those without prior renal impairment (PRI−). The GFR trend and the chronic kidney disease stage were evaluated at baseline, as well as at 1, 6, and 12 months after cryoablation. Predictors of GFR at 1 and 6 months were modeled with linear regression. Results: In both groups, the mean GFR at 1 month and 6 months was significantly lower than at baseline (p < 0.001 and p = 0.01, respectively). Although the GFR was lower across all time points in the PRI+ group (−26.1; p < 0.001), the overall trend was not statistically different from that observed in the PRI− group (p = 0.89). Univariate analysis showed that the decline in GFR at 1 and 6 months correlated with the baseline GFR (0.77 and 0.63; p < 0.001 and p = 0.03, respectively) and with the size of the ablation zone (−7.6 and −12.84, respectively; p = 0.03 for both). However, in the multivariate model, baseline GFR was predictive only of GFR at 1 month (p < 0.001). Conclusion: The trend in GFR decline after cryoablation is similar for patients with and without a history of renal impairment. Baseline GFR predicts the mean GFR in the early post-cryoablation period.
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Mathisen, Ulla Dorte, Toralf Melsom, Ole C. Ingebretsen, et al. "Estimated GFR Associates with Cardiovascular Risk Factors Independently of Measured GFR." Journal of the American Society of Nephrology 22, no. 5 (2011): 927–37. http://dx.doi.org/10.1681/asn.2010050479.
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Agarwal, Rajiv. "Estimating GFR from serum creatinine concentration: Pitfalls of GFR-estimating equations." American Journal of Kidney Diseases 45, no. 3 (2005): 610–13. http://dx.doi.org/10.1053/j.ajkd.2005.01.010.
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Goetschalckx, Elise, Djalila Mekahli, Elena Levtchenko, and Karel Allegaert. "Glomerular Filtration Rate in Former Extreme Low Birth Weight Infants over the Full Pediatric Age Range: A Pooled Analysis." International Journal of Environmental Research and Public Health 17, no. 6 (2020): 2144. http://dx.doi.org/10.3390/ijerph17062144.
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Various cohort studies document a lower glomerular filtration rate (GFR) in former extremely low birth weight (ELBW, <1000 g) neonates throughout childhood when compared to term controls. The current aim is to pool these studies to describe the GFR pattern over the pediatric age range. To do so, we conducted a systematic review on studies reporting on GFR measurements in former ELBW cases while GFR data of healthy age-matched controls included in these studies were co-collected. Based on 248 hits, 6 case-control and 3 cohort studies were identified, with 444 GFR measurements in 380 former ELBW cases (median age 5.3–20.7 years). The majority were small (17–78 cases) single center studies, with heterogeneity in GFR measurement (inulin, cystatin C or creatinine estimated GFR formulae) tools. Despite this, the median GFR (mL/min/1.73 m2) within case-control studies was consistently lower (−13%, range −8% to −25%) in cases, so that a relevant minority (15–30%) has a eGFR<90 mL/min/1.73 m2). Consequently, this pooled analysis describes a consistent pattern of reduced eGFR in former ELBW cases throughout childhood. Research should focus on perinatal risk factors for impaired GFR and long-term outcome, but is hampered by single center cohorts, study size and heterogeneity of GFR assessment tools.
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Klimontov, Vadim Valer'evich, Nadezhda Valentinovna Eremenko, Natalya Evgen'evna Myakina, and Olga Nikolaevna Fazullina. "Cystatin C and collagen type IV in diagnostics of chronic kidney disease in type 2 diabetic patients." Diabetes mellitus 18, no. 1 (2015): 87–93. http://dx.doi.org/10.14341/dm2015187-93.
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Aim. To compare kidney disease markers: glomerular filtration rate (GFR), calculated upon creatinine and cystatin C, urinary cystatin C, collagen type IV and albumin in type 2 diabetic patients with normal and moderately reduced renal function. Materials and methods. 56 patients, aged 43?70 years, and 16 healthy controls, aged 40-72 years, were included in the study. GFR was calculated by equations based on creatinine (CKD-EPIcreat), cystatin C (CKD-EPIcys) or both markers (CKD-EPIcreat-cys). Serum and urinary cystatin C was measured by immunoturbidimetric method, urinary albumin, albumin excretion rate (AER) and collagen type IV excretion was determined by ELISA. The body composition was investigated in 24 patients by dual-energy X-ray absorptiometry. Results. In diabetic patients serum cystatin C level correlated positively with age (r=0.37), GFR calculated by CKD-EPIcreat (r=-0.43) and fat mass percentage (r=0.55). There was a positive correlation between GFR calculated by the CKD-EPIcys and GFR by CKD-EPIcreat (r=0.48). In multiple regression analysis the percentage of body fat influenced the GFR calculated by CKD-EPIcys or CKD-EPIcreat-cys. No correlation between urinary cystatin C and serum cystatin C level, GFR and AER was found. Collagen type IV excretion was increased in patients with decreased GFR, compared to those with normal GFR (p=0.002). Urinary collagen type IV correlated with both GFR and AER (r=-0.28 and r=0.47). Conclusion. The measurement of serum cystatin C with calculation of GFR by CKD-EPIcys and CKD-EPIcreat-cys, in addition to the CKD-EPIcreat, increases the accuracy of CKD diagnostics in type 2 diabetic patients. However, obesity and particularly body fat mass affect the results of estimation of GFR based on cystatin C. The increase in urinary collagen type IV, but not in cystatin C excretion, is related to GFR decline and AER elevation in these patients.
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Jerums, George, Elif Ekinci, Sianna Panagiotopoulos, and Richard J. MacIsaac. "Early Glomerular Filtration Rate Loss as a Marker of Diabetic Nephropathy." US Endocrinology 08, no. 01 (2012): 40. http://dx.doi.org/10.17925/use.2012.08.01.40.
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In the early 1980s, studies in type 1 diabetes suggested that glomerular filtration rate (GFR) loss begins with the onset of macroalbuminuria. However, recent evidence indicates that up to one-quarter of subjects with diabetes reach a GFR of less than 60 ml/min/1.73 m2(chronic kidney disease [CKD] stage 3) before developing micro- or macroalbuminuria. Furthermore, the prospective loss of GFR can be detected in early diabetic nephropathy (DN) well before CKD stage 3. Early GFR loss usually reflects DN in type 1 diabetes but, in older patients with type 2 diabetes, the assessment of early GFR loss needs to take into account the effects of aging. The assessment of GFR is now feasible at clinical level, using formulas based on serum creatinine, age, gender, and ethnicity. Overall, the estimation of early GFR loss is more accurate with the Chronic Kidney Disease Epidemiology (CKD–EPI) formula than with the Modification of Diet in Renal Disease (MDRD) study formula, but there is some evidence that the CKD-EPI formula does not exhibit better performance than the MDRD formula for estimating GFR in diabetes. Both formulas underestimate GFR in the hyperfiltration range. Formulas based on the reciprocal of cystatin C can also be used to estimate GFR, but their cost and lack of assay standardization have delayed their use at clinical level. In summary, early GFR loss is an important marker of DN as well as a potentially reversible target for interventions in DN.
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Jerums, George, Elif Ekinci, Sianna Panagiotopoulos, and Richard J. MacIsaac. "Early Glomerular Filtration Rate Loss as a Marker of Diabetic Nephropathy." European Endocrinology 8, no. 1 (2010): 27. http://dx.doi.org/10.17925/ee.2012.08.01.27.
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In the early 1980s, studies in type 1 diabetes suggested that glomerular filtration rate (GFR) loss begins with the onset of macroalbuminuria. However, recent evidence indicates that up to one-quarter of subjects with diabetes reach a GFR of less than 60 ml/min/1.73 m2(chronic kidney disease [CKD] stage 3) before developing micro- or macroalbuminuria. Furthermore, the prospective loss of GFR can be detected in early diabetic nephropathy (DN) well before CKD stage 3. Early GFR loss usually reflects DN in type 1 diabetes but, in older patients with type 2 diabetes, the assessment of early GFR loss needs to take into account the effects of ageing. The assessment of GFR is now feasible at clinical level, using formulas based on serum creatinine, age, gender and ethnicity. Overall, the estimation of early GFR loss is more accurate with the Chronic Kidney Disease Epidemiology (CKD–EPI) formula than with the Modification of Diet in Renal Disease (MDRD) study formula, but there is some evidence that the CKD-EPI formula does not exhibit better performance than the MDRD formula for estimating GFR in diabetes. Both formulas underestimate GFR in the hyperfiltration range. Formulas based on the reciprocal of cystatin C can also be used to estimate GFR, but their cost and lack of assay standardisation have delayed their use at clinical level. In summary, early GFR loss is an important marker of DN as well as a potentially reversible target for interventions in DN.
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Wu, Congzhong, Lulu Wang, Zhen Yang, Jing Wang, Li Han, and Fei Li. "Convolution Neural Network for Renal Function Assessment Based on Glomerular Filtration Rate." Journal of Physics: Conference Series 2185, no. 1 (2022): 012033. http://dx.doi.org/10.1088/1742-6596/2185/1/012033.
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Absract ✓Objective: To develop a Convolution Neural Network (CNN) and discuss its performance in the estimation of Glomerular Fifiltration Rate (GFR) for patients with chronic kidney disease (CKD). Methods: A total of 112 patients with chronic kidney disease were enrolled in this study. The GFR is measured by 99mTc-DTPA renal dynamic and used as standard GFR after normalization by body surface area imaging. We established a CNN model and verified the performance of the model by comparing the GFR predicted by the model with the standard GFR. It turned out that the CNN could better evaluate the GFR of patients which is superior to the CG formula, MDRD formula, CKD-EPI formula and GRNN model. Conclusions: The CNN significantly evaluated GFR for patients with CKD, and it showed better performance than traditional methods and GRNN model and closer to the results of 99mTc-DTPA. The experimental results demonstrated that CNN could be used to estimate GFR.
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Stöhr, Wolfgang, A. Sarah Walker, Paula Munderi, et al. "Estimating Glomerular Filtration Rate in HIV-Infected Adults in Africa: Comparison of Cockcroft–Gault and Modification of Diet in Renal Disease Formulae." Antiviral Therapy 13, no. 6 (2008): 761–70. http://dx.doi.org/10.1177/135965350801300613.
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Background Cockcroft–Gault (CG) and Modification of Diet in Renal Disease (MDRD) formulae are recommended for glomerular filtration rate (GFR) estimation, but neither has been validated or directly compared longitudinally in HIV-infected patients or in Africa. Methods We investigated differences between formulae in baseline GFR, GFR changes and incidence of impaired GFR after initiation of antiretroviral therapy (ART) in 3,316 HIV-infected adults in Africa, considering sex, age, body mass index and baseline laboratory parameters as predictors. Results Participants were 65% women, median age 36.8 years, median weight 56.7 kg. Baseline GFR was lower using CG (median 89 ml/min/1.73 m2, 7.4% <60 ml/ min/1.73 m2) versus MDRD (103 ml/min/1.73 m2, 3.1% <60 ml/min/1.73 m2). At 36 weeks, median CG-GFR increased (92 ml/min/1.73 m2), whereas MDRD-GFR decreased (96 ml/min/1.73 m2). Weight (explicitly a factor in CG only) concurrently increased to 62.0 kg. GFR changes from weeks 36–96 (after weight stabilization) were similar across formulae. By 96 weeks, 56 patients developed severe GFR impairment (<30 ml/min/1.73 m2) using one or both formulae (both n=45, CG n=7, MDRD n=4) compared with only 24 by serum creatinine alone. Multivariate models identified different sets of predictors for each formula. Conclusions Although severe GFR impairments are similarly classified by different formulae, moderate impairments were more frequently identified using CG-GFR versus MDRD-GFR (with Black ethnicity correction factor 1.21), and creatinine alone had low sensitivity. Given overestimation in underweight patients and sensitivity to weight changes, this MDRD formula might not necessarily be superior for monitoring ART in African HIV-infected adults.
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Yan, Ruohua, Chao Zhang, Chen Wang, Zimo Sun, and Xiaoxia Peng. "Evaluation of glomerular filtration rate estimation equations based on serum creatinine in healthy Chinese children and adolescents: a nationwide cross-sectional study." BMJ Paediatrics Open 7, no. 1 (2023): e002132. http://dx.doi.org/10.1136/bmjpo-2023-002132.
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BackgroundSeveral equations for glomerular filtration rate (GFR) estimation based on serum creatinine (SCr) have been proposed for children, but most were developed among patients with kidney disease. The association between SCr and GFR may be distorted by kidney dysfunction and thus not applicable to healthy children. This study aimed to evaluate the applicability of existing SCr-based GFR estimation equations in healthy Chinese children.MethodsGFR estimation equations that developed in healthy children were mainly analysed, including the Flanders Metadata (FM), simple height-independent (Simple), full age spectrum (FAS) and FAS-height equations. The FM equation assumed that GFR is proportional to the ratio of height to SCr. The Simple, FAS and FAS-height equations assumed that the ratio of GFR to population mean is equal to the reciprocal ratio of SCr to population mean (denoted by Q). Estimated GFR were calculated using data of SCr, age, sex and height collected from 12 208 healthy Chinese children aged 3 months to <20 years. The performance of GFR estimation equations was evaluated by the sex and age distribution of the estimated GFR and the deviation from the measured GFR reported by other literatures.ResultsThe FM and Simple equations performed well in their applicable age of 1 month to 14 years, but presented undesirable sex difference after adolescence. The FAS and FAS-height equations showed reasonable development trend of estimated GFR throughout childhood, and the FAS equation had higher consistency than the FAS-height equation compared with measured GFR in healthy children. The GFR estimated by the FAS equation increased with age before 2 years, and reached the adult level thereafter without important sex difference.ConclusionsThe FAS equation is applicable to healthy Chinese children.
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Hornum, Mads, Morten Baltzer Houlind, Esben Iversen, et al. "Estimating Renal Function Following Lung Transplantation." Journal of Clinical Medicine 11, no. 6 (2022): 1496. http://dx.doi.org/10.3390/jcm11061496.
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Background: Patients undergoing lung transplantation (LTx) experience a rapid decline in glomerular filtration rate (GFR) in the acute postoperative period. However, no prospective longitudinal studies directly comparing the performance of equations for estimating GFR in this patient population currently exist. Methods: In total, 32 patients undergoing LTx met the study criteria. At pre-LTx and 1-, 3-, and 12-weeks post-LTx, GFR was determined by 51Cr-EDTA and by equations for estimating GFR based on plasma (P)-Creatinine, P-Cystatin C, or a combination of both. Results: Measured GFR declined from 98.0 mL/min/1.73 m2 at pre-LTx to 54.1 mL/min/1.73 m2 at 12-weeks post-LTx. Equations based on P-Creatinine underestimated GFR decline after LTx, whereas equations based on P-Cystatin C overestimated this decline. Overall, the 2021 CKD-EPI combination equation had the lowest bias and highest precision at both pre-LTx and post-LTx. Conclusions: Caution must be applied when interpreting renal function based on equations for estimating GFR in the acute postoperative period following LTx. Simplified methods for measuring GFR may allow for more widespread use of measured GFR in this vulnerable patient population.
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Murray, R. D., S. Itoh, T. Inagami, et al. "Effects of synthetic atrial natriuretic factor in the isolated perfused rat kidney." American Journal of Physiology-Renal Physiology 249, no. 4 (1985): F603—F609. http://dx.doi.org/10.1152/ajprenal.1985.249.4.f603.
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It is known that atrial extracts (AE) and synthetic atrial natriuretic factor (ANF) can increase glomerular filtration rate (GFR) and electrolyte and water excretion both in vivo and in vitro. It is not clear, however, if ANF-induced increases in filtered load (increased GFR) are required to produce natriuresis and diuresis. We perfused isolated rat kidneys with AE or synthetic ANF at constant pressure in a single-pass system. Extracts of atrial tissue (1 mg/ml) and high concentrations of ANF (31 and 61 ng/ml) significantly increased both GFR and electrolyte and water excretion. During continued infusion of ANF, GFR stabilized at increased levels, but sodium and water excretion continued to increase. After the termination of infusions, GFR and potassium excretion returned to control levels, but sodium and water excretion remained significantly elevated. Infusion of a low concentration of ANF (3 ng/ml) significantly increased sodium and water excretion without changing either GFR or potassium excretion. We conclude that increases in GFR are not a prerequisite for natriuresis and diuresis in response to ANF, but that increases in GFR can potentiate the response. Furthermore, our data suggest that ANF increases potassium excretion only if it increases GFR.
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Levey, A. S., T. Greene, M. D. Schluchter, et al. "Glomerular filtration rate measurements in clinical trials. Modification of Diet in Renal Disease Study Group and the Diabetes Control and Complications Trial Research Group." Journal of the American Society of Nephrology 4, no. 5 (1993): 1159–71. http://dx.doi.org/10.1681/asn.v451159.
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To assess the utility and precision of GFR measurements in multicenter trials, the test performance and variability of GFR were analyzed in 2,250 patients enrolled in 44 clinical centers participating in either the Modification of Diet in Renal Disease (MDRD) Study or the Diabetes Control and Complications Trial (DCCT). GRF was measured as the renal clearance of [125I]iothalamate after an sc injection without epinephrine. The studies used similar protocols for obtaining blood and urine, training clinical center staff, and processing specimens in central laboratories. The performance of GFR measurements, assessed from adherence to protocol and quality control analyses, was excellent. The variability among the four clearance periods (intratest coefficient of variation [CV]) was acceptable; the median intratest CV for GFR was 9.4% in the MDRD Study and 11.7% in the DCCT. The pattern of decline in serum counts was better approximated by an exponential rather than a linear relationship. The cause of the intratest variability in GFR measurements was explored by univariate and multivariate analysis. The intratest CV was highest at the extremes of GFR. Among patients with a high GFR (> 90 mL/min per 1.73 m2), most of whom were participants in the DCCT, the higher intratest GFR was due, in part, to a systematic decline in GFR during the test. Among patients with a very low GFR (< 13 mL/min per 1.73 m2), technical difficulties in urine collections contributed substantially to the higher intratest CV. Other patient characteristics, including age, gender, weight, serum glucose, renal diagnosis, and use of diuretics, were not strongly correlated with the intratest CV. The precision of GFR measurements was assessed from the variability from measurement to measurement (interest CV). Among MDRD Study subjects, in whom two measurements of GFR were performed over a 3-month interval, the median interest CV was relatively low (6.3%) and was only weakly related to the intratest CV. Thus, GFR measurements are reasonably precise, even if the intratest CV is high. Given the relatively high intratest CV that is characteristic of GFR measurements, the estimate of GFR in an individual is more precise if multiple clearance periods, rather than a single period, are included. Similarly, the estimate of mean GFR for a population is also more precise if multiple clearance periods are included. In conclusion, by the use of standardized methods, an acceptable precision of GFR results can be obtained in multicenter trials. The same methods can be applied in clinical practice.(ABSTRACT TRUNCATED AT 400 WORDS)
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PETERS, A. M., B. L. HENDERSON, and D. LUI. "Indexed glomerular filtration rate as a function of age and body size." Clinical Science 98, no. 4 (2000): 439–44. http://dx.doi.org/10.1042/cs0980439.
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The conventional way in which to scale or index a measurement of glomerular filtration rate (GFR) is to express it in relation to body surface area (BSA). However, BSA may not be appropriate for infants and children because, as individuals increase in size, their relative BSA decreases. Several other whole-body variables have been suggested as alternatives, including extracellular fluid volume (vECF). The purpose of the present study was to compare BSA and vECF as variables against which to index GFR, and in particular to look at this comparison in children versus adults. A total of 130 patients (age range 1–80 years; 40 patients < 12 years) undergoing clinically indicated routine measurement of GFR using the bolus-injection single-compartment technique were included in the study. GFR was measured as the plasma clearance of [51Cr]EDTA as assessed from three peripheral venous blood samples taken between 2 and 4 h after injection of [51Cr]EDTA. Volume of distribution (Vd) was obtained by extrapolation of the clearance curve to zero time. GFR was scaled to a BSA of 1.73 m2. GFR and GFR/1.73 m2 were corrected to account for the assumption of a single compartment. The rate constant of the exponential between 2 and 4 h was also corrected to give GFR/litre ECF. GFR and GFR/1.73 m2 were both divided by GFR/litre ECF, to give vECF and vECF/1.73 m2 respectively. Weight per unit BSA increases as a linear function of BSA. vECF is always less than Vd, on average by about 30%. vECF increased as an exponential function of BSA and as a linear function of body weight. vECF/70 kg body weight was higher in children (16.2±3 litres) than adults (13.4±2.3 litres), but vECF/1.73 m2 was lower in children (9.7±1.7 litres) compared with adults (12.4±2 litres). vECV/1.73 m2 increased as a function of both age and BSA, but vECF/kg decreased. GFR/12.5 litres vECF was higher than GFR/1.73 m2 in children, but these values were similar in adults, with the ratio of these two forms of indexed GFR falling significantly with both age and BSA. Although this was not a normal population, but one with a wide range of renal function, GFR/vECF showed a strong inverse association with age, whereas for GFR/BSA the association was weak. In conclusion, these data provide further evidence that vECF is more valid physiologically for indexing GFR than is BSA, especially in children. Nevertheless, a GFR measurement in a child should ideally be expressed as a percentage of normal for that child's age. However, such normal values are not yet available.
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de Souza, Jonas A., Rima Saliba, Poliana A. Patah, et al. "Renal Function Impairment and Outcomes of Reduced-Intensity Allogeneic Hematopoietic Stem Cell Transplantation." Blood 108, no. 11 (2006): 48. http://dx.doi.org/10.1182/blood.v108.11.48.48.
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Abstract Non-relapse mortality (NRM) after reduced-intensity allogeneic transplants is likely to be influenced by abnormalities in renal function. We hypothesized that moderate to mild renal function impairment increases NRM in this setting. Methods: We studied 141 patients diagnosed with AML (n=131) or high-risk MDS (n=10) who underwent allogeneic transplantation with Fludarabine (Flu)/Melphalan (Mel)-based regimens between August 1996, and May 2006 in our institution. Flu dose was 30–40mg/m2 for 4 days and Mel doses were100–180mg/m2. ATG was added for recipients of unrelated donor (UD) HSCT. GVHD prophylaxis was tacrolimus and mini-methotrexate for all but 2 patients. Donors were HLA-compatible siblings (n=69) and matched UD (n=72). Disease status at transplant was complete remission (n=56, 40%) or active disease (n=85, 60%). The influence of the estimated glomerular filtration rate (GFR) measured before transplant on outcomes was analyzed. GFR was calculated by both the Cockcroft Gault (CG) and the Modified Diet in Renal Disease (MDRD) equations, using the creatinine value obtained prior to starting chemotherapy. We considered GFR ≥ 90 as normal and GFR &lt; 90 as decreased. Evaluated outcomes were overall survival, NRM, and regimen-related mortality (RRM) at day 100 and 1-year post transplant. Results: Median age was 55 years (range, 21–74); 59% of the patients were male. Estimated GFR by CG was normal for 45 patients (32%), and decreased for 96 patients (68%). When estimated by MDRD, 65 patients (46%) had normal and 76 (54%) had reduced GFR. The majority of patients by both estimations had a GFR between 60 and 89 (n= 78 by CG and n= 66 by MDRD) with no difference in the evaluated outcomes between this group and the subgroup of patients with a GFR &lt;60 (p&gt;0.05). There was no difference in overall and NRM at day 100 and 1 year post transplant in both groups by any GFR estimation method. There was a small trend towards lower RRM at day-100 for patients with GFR ≥ 90 when using CG, but this was not statistically significant. Conclusion: A mild to moderate decrease in GFR is not associated with an increase in non-relapse mortality. Transplant outcomes as a function of GFR at start of conditioning regimen Outcome N 100-Day Mortality HR p 1-year Mortality HR p Abbreviations: NRM: non-relapse mortality; RRM: regimen-related mortality (excludes deaths due to GVHD); GFR: glomerular filtration rate (estimated by CG) Survival- GFR ≥ 90 45 11 (25%) 0.9 0.9 24 (53%) 1.2 0.5 Survival- GFR &lt; 90 96 24 (25%) 44 (46%) NRM* - GFR ≥ 90 45 9 (21%) 0.9 0.9 14 (31%) 0.98 0.9 NRM* - GFR &lt; 90 96 19 (20%) 31 (32%) RRM* - GFR ≥ 90 45 3 (7%) 0.5 0.3 6 (13%) 0.9 0.9 RRM* - GFR &lt; 90 96 12 (13%) 14 (15%)
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Greene, Tom, Jian Ying, Edward F. Vonesh, et al. "Performance of GFR Slope as a Surrogate End Point for Kidney Disease Progression in Clinical Trials: A Statistical Simulation." Journal of the American Society of Nephrology 30, no. 9 (2019): 1756–69. http://dx.doi.org/10.1681/asn.2019010009.
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BackgroundRandomized trials of CKD treatments traditionally use clinical events late in CKD progression as end points. This requires costly studies with large sample sizes and long follow-up. Surrogate end points like GFR slope may speed up the evaluation of new therapies by enabling smaller studies with shorter follow-up.MethodsWe used statistical simulations to identify trial situations where GFR slope provides increased statistical power compared with the clinical end point of doubling of serum creatinine or kidney failure. We simulated GFR trajectories based on data from 47 randomized treatment comparisons. We evaluated the sample size required for adequate statistical power based on GFR slopes calculated from baseline and from 3 months follow-up.ResultsIn most scenarios where the treatment has no acute effect, analyses of GFR slope provided similar or improved statistical power compared with the clinical end point, often allowing investigators to shorten follow-up by at least half while simultaneously reducing sample size. When patients’ GFRs are higher, the power advantages of GFR slope increase. However, acute treatment effects within several months of randomization can increase the risk of false conclusions about therapies based on GFR slope. Care is needed in study design and analysis to avoid such false conclusions.ConclusionsUse of GFR slope can substantially increase statistical power compared with the clinical end point, particularly when baseline GFR is high and there is no acute effect. The optimum GFR-based end point depends on multiple factors including the rate of GFR decline, type of treatment effect and study design.
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Fino, Nora F., Lesley A. Inker, Tom Greene, et al. "Panel estimated Glomerular Filtration Rate (GFR): Statistical considerations for maximizing accuracy in diverse clinical populations." PLOS ONE 19, no. 12 (2024): e0313154. https://doi.org/10.1371/journal.pone.0313154.
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Assessing glomerular filtration rate (GFR) is critical for diagnosis, staging, and management of kidney disease. However, accuracy of estimated GFR (eGFR) is limited by large errors (>30% error present in >10–50% of patients), adversely impacting patient care. Errors often result from variation across populations of non-GFR determinants affecting the filtration markers used to estimate GFR. We hypothesized that combining multiple filtration markers with non-overlapping non-GFR determinants into a panel GFR could improve eGFR accuracy, extending current recognition that adding cystatin C to serum creatinine improves accuracy. Non-GFR determinants of markers can affect the accuracy of eGFR in two ways: first, increased variability in the non-GFR determinants of some filtration markers among application populations compared to the development population may result in outlying values for those markers. Second, systematic differences in the non-GFR determinants of some markers between application and development populations can lead to biased estimates in the application populations. Here, we propose and evaluate methods for estimating GFR based on multiple markers in applications with potentially higher rates of outlying predictors than in development data. We apply transfer learning to address systematic differences between application and development populations. We evaluated a panel of 8 markers (5 metabolites and 3 low molecular weight proteins) in 3,554 participants from 9 studies. Results show that contamination in two strongly predictive markers can increase imprecision by more than two-fold, but outlier identification with robust estimation can restore precision nearly fully to uncontaminated data. Furthermore, transfer learning can yield similar results with even modest training set sample size. Combining both approaches addresses both sources of error in GFR estimates. Once the laboratory challenge of developing a validated targeted assay for additional metabolites is overcome, these methods can inform the use of a panel eGFR across diverse clinical settings, ensuring accuracy despite differing non-GFR determinants.
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Abrishami, Zahra, Mitra Mahdavi-Mazdeh, Farzanehsadat Minoo, and Monireh Amerian. "Cystatin C versus creatinine-based GFR formula in CKD patients." BANTAO Journal 12, no. 1 (2015): 33–35. http://dx.doi.org/10.2478/bj-2014-0007.
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AbstractIntroduction.Glomerular Filtration Rate (GFR) is the main tool to assess kidney function. Some experts suggest cystatin C as a more precise and accurate indicator than creatinine to calculate GFR. This study is designed to assess if cystatin C is more helpful in early diagnosis and better follow-up of Chronic Kidney Disease (CKD) patients who may benefit more from appropriate and timely management.Methods.We studied 312 patients in different stages of CKD and normal kidney function as control. GFR based on creatinine (Jaffe and enzymatic) and cystatin C were calculated and compared.Results.A total of 146(46.8%) patients were male with a mean age of 53±17.5 years. The patients were divided into 3 groups based on GFR (>60 cc/min/1.73m 2, 30< GFR<60cc/min/1.73m 2, 15<GFR<30cc/min/1.73m 2). No significant differences in GFR estimation based on creatinine and cystatin C were found.Conclusions.There were no significant differences between serum cystatin C-based formula and creatinine-based formula for GFR calculation. Therefore, they can be used interchangeably.
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Cattik, Busra Nur, and Rashida Muhammad Umar. "COMPARISON OF ESTIMATED GLOMERULAR FILTRATION RATE USING DIFFERENT FORMULAS IN TURKISH POPULATION." Ankara Universitesi Eczacilik Fakultesi Dergisi 48, no. 3 (2024): 5. http://dx.doi.org/10.33483/jfpau.1458525.
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Objective: Creatinine-based equations are generally used in clinical practice to estimate glomerular filtration rates (GFR), but values are not usually consistent. This study aimed to evaluate the difference between estimated GFR values using different equations. Material and Method: Adult Turkish patients with serum creatinine measurements between January to December 2021 and complete demographic data were included. GFR values were calculated using 5 different formulas. GFR calculated with Cockcroft-Gault were normalized to body surface area and added to the comparison. Difference between GFR values and KDIGO stages were evaluated. Albunin/creatinine ratio (ACR) of patients was also assessed. Result and Discussion: A total of 305 patients with average age of 52.92 years were included. Six different GFR calculations were recorded with median values between 51.70 to 71.77 ml/min/1.73m2. Formula of The Modification of Diet in Renal Disease with the race factor for Turkish population resulted in the lowest eGFR values. The ACR values of only 42 patients were available and it was negatively correlated to all GFR values and positively correlated to all KDIGO stages (p&lt;0.05). There were noteworthy variations in GFR values, based on patient demographics and/or equations. The need for novel practical methods for estimating GFR in general and specific patient populations are necessary.
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Sapru, Shantanu, Nilotpal Choudhary, Abhilash Chandra, Rimpa Mudi, Rahul Tripathi, and Satyawati Deswal. "Comparing the Reliability of the Glomerular Filtration Rate Estimated with 99m-Technetium Diethylene-Triamine-Pentaacetate versus the Effective Renal Plasma Flow Obtained with 99m-Technetium Ethylene Dicysteine: A Prospective Observational Study." Saudi Journal of Kidney Diseases and Transplantation 34, no. 1 (2023): 21–33. http://dx.doi.org/10.4103/1319-2442.390999.
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The glomerular filtration rate (GFR) is important for assessing renal function and must be calculated reliably and reproducibly. This study aimed to compare the reliability and accuracy of GFR estimated with 99m-technetium diethylene-triamine-pentaacetate (99mTc-DTPA) versus that calculated from the effective renal plasma flow (ERPF) (GFR is 20% of ERPF) determined by the 99m-technetium ethylene dicysteine (99mTc-EC) technique. Forty-five patients suffering from cancer requiring platinum compound-based chemotherapy or from chronic renal failure were recruited. The patients were divided into two cohorts: (1) those with normal serum creatinine (SCr) levels (≤2 mg/dL) and (2) deranged SCr levels (>2 mg/dL). For all patients, the relative renal function was estimated by the 99mTc-DTPA and 99mTc-EC methods, 2–4 days apart. A 24-h urine sample for estimating 24-h creatinine clearance (CrCl) was obtained. GFR was also calculated using the Modification of Diet in Renal Disease (MDRD) formula. The GFR estimated via 24-h urine CrCl, 99mTc-DTPA, and ERPF obtained with 99mTc-EC were examined by quantile comparison plots, and all showed evidence of following a non-Gaussian distribution. For SCr values ≤2 mg/dL, the GFR estimated by the MDRD formula consistently shows significantly higher values than the GFR estimated with 99mTc-DTPA or 99mTc-EC. We found a high degree of correlation between the 99mTc-DTPA and 99mTc-EC radionuclide methods of estimating GFR. However, in patients with renal dysfunction, GFR estimated through Gates' method using a gamma camera overestimated the GFR; in these patients, calculating the GFR from the ERPF obtained with 99mTc-EC is more accurate.