Glomerular Filtration Rate Estimation Equations Research Articles

The EKFC equation outperforms the CKD-EPI and CKiD equations for GFR estimation in adolescent and young adult kidney transplant patients.

This study evaluated the bias and accuracy of the CKD-EPI/CKiD and EKFC equations compared with the reference exogenous tracer-based assessment of glomerular filtration rate (GFR) in adult and pediatric patients according to their renal transplant status. We assessed the bias and P30 accuracy of the CKD-EPI/CKiD and EKFC equations compared with iohexol-based GFR measurement. In the overall population (n = 59), the median age was 29 years (IQR, 16.0-46.0) and the median measured GFR was 73.9 mL/min/1.73m2 (IQR, 57.3-84.6). Among non-kidney transplant patients, the median was 77.7 mL/min/1.73m2 (IQR, 59.3-86.5), while among kidney transplant patients, it was 60.5 mL/min/1.73m2 (IQR, 54.2-66.8). The bias associated with the EKFC and CKD-EPI/CKiD equations was significantly higher among kidney transplant patients than among non-kidney transplant patients, with a difference between medians (Hodges-Lehmann) of +10.4 mL/min/1.73m2 (95% CI, 2.2-18.9; p = .02) for the EKFC and +12.1 mL/min/1.73m2 (95% CI, 4.2-21.4; p = .006) for the CKD-EPI/CKiD equations. In multivariable analysis, kidney transplant status emerged as an independent factor associated with a bias of >3.4 mL/min/1.73m2 (odds ratio, 7.7; 95% CI, 1.4-43.3; p = .02) for the EKFC equation and a bias of >13.4 mL/min/1.73m2 (odds ratio, 15.0; 95% CI, 2.6-85.7; p = .002) for the CKD-EPI/CKiD equations. In our study, which included adolescent and young adult kidney transplant patients, both the CKD-EPI/CKiD and EKFC equations tended to overestimate the measured glomerular filtration rate, with the EKFC equation exhibiting less bias. Renal transplant status significantly influenced the degree of estimation bias.

Bias and Accuracy of Glomerular Filtration Rate Estimating Equations in the US

There is increasing concern that continued use of a glomerular filtration rate (GFR) estimating equation adjusted for a single racial group could exacerbate chronic kidney disease-related disparities and inequalities. To assess the performance of GFR estimating equations across varied patient populations. PubMed, Embase, Web of Science, ClinicalTrials.gov, and Scopus databases were systematically searched from January 2012 to February 2023. Inclusion criteria were studies that compared measured GFR with estimated GFR in adults using established reference standards and methods. A total of 6663 studies were initially identified for screening and review. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, 2 authors independently extracted data on studies that examined the bias and accuracy of GFR estimating equations. For each outcome, a random-effects model was used to calculate pooled estimates. Data analysis was conducted from March to December 2023. The primary outcomes were bias and accuracy of estimated GFRs in Black vs non-Black patients, as well as in individuals with chronic conditions. Bias was defined as the median difference between the measured GFR and the estimated GFR. Accuracy was assessed with P30 (the proportion of persons in a data set whose estimated GFR values were within 30% of measured GFR values) and measures of heterogeneity. A total of 12 studies with a combined 44 721 patients were included. Significant heterogeneity was found in the bias of various GFR estimation equations. Race-corrected equations and creatinine-based equations tended to overestimate GFR in Black populations and showed mixed results in non-Black populations. For creatinine-based equations, the mean bias in subgroup analysis was 2.1 mL/min/1.73 m2 (95% CI, -0.2 mL/min/1.73 m2 to 4.4 mL/min/1.73 m2) in Black persons and 1.3 mL/min/1.73 m2 (95% CI, 0.0 mL/min/1.73 m2 to 2.5 mL/min/1.73 m2) in non-Black persons. Equations using only cystatin C had small biases. Regarding accuracy, heterogeneity was high in both groups. The overall P30 was 84.5% in Black persons and 87.8% in non-Black persons. Creatinine-based equations were more accurate in non-Black persons than in Black persons. For creatinine-cystatin C equations, the P30 was higher in non-Black persons. There was no significant P30 difference in cystatin C-only equations between the 2 groups. In patients with chronic conditions, P30 values were generally less than 85%, and the biases varied widely. This systematic review and meta-analysis of GFR estimating equations suggests that there is bias in race-based GFR estimating equations, which exacerbates kidney disease disparities. Development of a GFR equation independent of race is a crucial starting point, but not the sole solution. Addressing the disproportionate burden of kidney failure on Black individuals in the US requires an enduring, multifaceted approach that should include improving diagnostics, tackling social determinants of health, confronting systemic racism, and using effective disease prevention and management strategies.

Performance evaluation of Chronic Kidney Disease Epidemiology Collaboration equations for estimated glomerular filtration rate compared to inulin clearance in Koreans.

A race-free glomerular filtration rate (GFR) estimation equation has recently been developed. However, the performance of the new Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations needs to be evaluated in Asian populations. We performed a cross-sectional study at a single center in South Korea. The measured GFR (mGFR) was determined based on systemic inulin clearance. The GFR was estimated using the five CKD-EPI equations: 2009 CKD-EPIcr, 2012 CKD-EPIcr-cys, 2012 CKD-EPIcys, 2021 CKD-EPIcr, and 2021 CKD-EPIcr-cys. The performances of five estimated GFR (eGFR) equations were assessed by bias, precision, and accuracy (percentage of estimates within 30% of mGFR). The median mGFR and interquartile range (IQR) was 53.5 (32.4-80.0) mL/min/1.73 m2. The mGFR better correlated with 2009 CKD-EPIcr (ρ = 0.628) and 2021 CKD-EPIcr-cys (ρ = 0.806) than with 2021 CKD-EPIcr (ρ = 0.623) and 2012 CKD-EPIcr-cys (ρ = 0.801). The median bias of 2009 CKD-EPIcr and 2012 CKD-EPIcr-cys were lower than those of 2021 CKD-EPI equations (2009 CKD-EPIcr, 2.24 [IQR, -8.83 to 17.39] vs. 2021 CKD-EPIcr, 5.40 [IQR, -6.04 to 20.40]; 2012 CKD-EPIcr-cys, 6.74 [IQR, -2.81 to 20.80] vs. 2021 CKD-EPIcr-cys, 10.54 [IQR, 0.30-24.37]; all in mL/min/1.73 m2). The percentage of eGFR values within 30% of mGFR was higher in 2009 CKD-EPIcr and 2012 CKD-EPIcr-cys equations than 2021 CKD-EPI equations. The CKD prevalence in 2009 CKD-EPIcr, 2021 CKD-EPIcr, 2012 CKD-EPIcr-cys, and 2021 CKD-EPIcr-cys was 54.8%, 51.0%, 47.7%, and 44.8%, respectively. Our study demonstrated better performance of the original CKD-EPIcr and CKD-EPIcr-cys equations than the 2021 new CKD-EPI equations. We do not recommend the adoption of the new CKD-EPI equations in Korea.

Evaluation of glomerular filtration rate estimation equations based on serum creatinine in healthy Chinese children and adolescents: a nationwide cross-sectional study

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...

Rescaling creatinine makes GFR estimation equations generally applicable across populations - validation results for the Lund-Malmö equation in a French cohort of sub-Saharan ancestry.

To make glomerular filtration rate (GFR) estimating equations applicable across populations with different creatinine generation by using rescaled serum creatinine (sCr/Q) where sCr represents the individual creatinine level and Q the average creatinine value in healthy persons of the same population. GFR measurements (mGFR, plasma clearance of 51Cr-EDTA) were conducted in 964 adult Black Europeans. We established the re-expressed Lund-Malmö revised equation (r-LMR) by replacing serum creatinine (sCr) with rescaled creatinine sCr/Q. We evaluated the r-LMR equation based on Q-values of White Europeans (r-LMRQ-white; Q-values females: 62 μmol/L, males: 80 μmol/L) and Black Europeans (r-LMRQ-Black; Q-values females: 65 μmol/L, males: 90 μmol/L), and the European Kidney Function Consortium equation (EKFCQ-White and EKFCQ-Black) regarding bias, precision (interquartile range, IQR) and accuracy (percentage of estimates within ±10 % [P10] and ±30 % [P30] of mGFR). Median bias of r-LMRQ-White/r-LMRQ-Black/EKFCQ-White/EKFCQ-Black were -9.1/-4.5/-6.3/-0.9 mL/min/1.73 m2, IQR 14.7/14.5/14.5/15.6 mL/min/1.73 m2, P10 25.1 %/34.8 %/30.3 %/37.2 % and P30 74.2 %/84.1 %/80.6 %/83.6 %. The improvement of bias and accuracy when using proper Q-values was most pronounced in men. Similar improvements were obtained above and below mGFR 60 mL/min/1.73 m2 and at various age and BMI intervals, except for BMI<20 kg/m2 where bias increased, and accuracy decreased. GFR estimating equations may be re-expressed to include rescaled creatinine (sCr/Q) and used across populations with different creatinine generation if population-specific average creatinine concentrations (Q-values) for healthy persons are established.

Comparison of GFR measurement with a two-blood sample technique using [99mTc]Tc-DTPA vs. creatinine-based equations in potential kidney donors.

Accurate determination of glomerular filtration rate (GFR) is crucial for selection of kidney donors. Nuclear medicine methods are considered accurate in measuring GFR but are not always easily available. The four-variable Modification of Diet in Renal Disease (MDRD4), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), and Full Age Spectrum (FAS) formulas are common equations for estimating GFR and are recommended for initial assessment of kidney donors. The aim of this study was to evaluate the performance of these GFR estimation equations compared with technetium-99m diethylenetriaminepentaacetic acid ([99mTc]Tc-DTPA) clearance. We compared GFR estimation by [99mTc]Tc-DTPA clearance using a two-blood sample method with estimation by MDRD4, CKD-EPI, and FAS creatinine-based equations in a population of healthy potential kidney donors. A total of 195 potential kidney donors (68.2% female; mean age 49 years, range 21-75 years) were included in this study. Mean [99mTc]Tc-DTPA measured GFR (mGFR) was 101.5 ± 19.1 mL/min/1.73 m2. All three equations underestimated the GFR value measured by [99mTc]Tc-DTPA (MDRD4: -11.5 ± 18.8 mL/min/1.73 m2; CKD-EPI: -5.0 ± 17.4 mL/min/1.73 m2; FAS: -8.3 ± 17.4 mL/min/1.73 m2). Accuracy within 30% and 10% of the measured GFR value was highest for CKD-EPI. The CKD-EPI equation showed better performance in estimating GFR in healthy potential kidney donors, proving to be a more accurate tool in the initial assessment of kidney donors. However, creatinine-based equations tended to underestimate kidney function. Therefore, GFR should be confirmed by another method in potential kidney donors.

A back propagation neural network approach to estimate the glomerular filtration rate in an older population

BackgroundThe use of creatinine-based glomerular filtration rate (GFR)-estimating equations to evaluate kidney function in elderly individuals does not appear to offer any performance advantages. We therefore aimed to develop an accurate GFR-estimating tool for this age group.MethodsAdults aged ≥ 65 years who underwent GFR measurement by technetium-99 m-diethylene triamine pentaacetic acid (99mTc-DTPA) renal dynamic imaging were included. Data were randomly split into a training set containing 80% of the participants and a test set containing the remaining 20% of the subjects. The Back propagation neural network (BPNN) approach was used to derive a novel GFR estimation tool; then we compared the performance of the BPNN tool with six creatinine-based equations (Chronic Kidney Disease-Epidemiology Collaboration [CKD-EPI], European Kidney Function Consortium [EKFC], Berlin Initiative Study-1 [BIS1], Lund-Malmö Revised [LMR], Asian modified CKD-EPI, and Modification of Diet in Renal Disease [MDRD]) in the test cohort. Three equation performance criteria were considered: bias (difference between measured GFR and estimated GFR), precision (interquartile range [IQR] of the median difference), and accuracy P30 (percentage of GFR estimates that are within 30% of measured GFR).ResultsThe study included 1,222 older adults. The mean age of both the training cohort (n = 978) and the test cohort (n = 244) was 72 ± 6 years, with 544 (55.6%) and 129 (52.9%) males, respectively. The median bias of BPNN was 2.06 ml/min/1.73 m2, which was smaller than that of LMR (4.59 ml/min/1.73 m2; p = 0.03), and higher than that of the Asian modified CKD-EPI (-1.43 ml/min/1.73 m2; p = 0.02). The median bias between BPNN and each of CKD-EPI (2.19 ml/min/1.73 m2; p = 0.31), EKFC (-1.41 ml/min/1.73 m2; p = 0.26), BIS1 (0.64 ml/min/1.73 m2; p = 0.99), and MDRD (1.11 ml/min/1.73 m2; p = 0.45) was not significant. However, the BPNN had the highest precision IQR (14.31 ml/min/1.73 m2) and the greatest accuracy P30 among all equations (78.28%). At measured GFR < 45 ml/min/1.73 m2, the BPNN has highest accuracy P30 (70.69%), and highest precision IQR (12.46 ml/min/1.73 m2). The biases of BPNN and BIS1 equations were similar (0.74 [-1.55−2.78] and 0.24 [-2.58−1.61], respectively), smaller than any other equation.ConclusionsThe novel BPNN tool is more accurate than the currently available creatinine-based GFR estimation equations in an older population and could be recommended for routine clinical use.

WCN23-0447 Precision and Agreement of Glomerular Filtration Rate estimation equations for chemotherapy dosing in cancer patients at St Paul’s Hospital Millennium Medical College, Addis Ababa, Ethiopia

WCN23-0447 Precision and Agreement of Glomerular Filtration Rate estimation equations for chemotherapy dosing in cancer patients at St Paul’s Hospital Millennium Medical College, Addis Ababa, Ethiopia

Measuring Creatinine Clearance Is the Most Accurate Way for Calculating the Proper Continuous Infusion Meropenem Dose for Empirical Treatment of Severe Gram-Negative Infections among Critically Ill Patients

Assessment of glomerular filtration rate (GFR) is necessary for dose adjustments of beta-lactam that are excreted by the kidneys, such as meropenem. The aim of this study was to compare the daily dose of 24 h-continuous infusion (CI) meropenem when GFR was calculated by means of measured creatinine clearance (mCLCR) or estimated by the CKDEPI (eGFRCKDEPI), Cockcroft-Gault (eGFRCG), and MDRD (eGFRMDRD) equations. Adult critically ill patients who underwent therapeutic drug monitoring (TDM) for the assessment of 24 h-CI meropenem steady state concentration (Css) and for whom a 24 h-urine collection was performed were retrospectively enrolled. Meropenem clearance (CLM) was regressed against mCLCR, and meropenem daily dose was calculated based on the equation infusion rate = daily dose/CLM. eGFRCKDEPI, eGFRCG, and eGFRCKDEPI were regressed against mCLCR in order to estimate CLM. Forty-six patients who provided 133 meropenem Css were included. eGFRCKDEPI overestimated mCLCR up to 90 mL/min, then mCLCR was underestimated. eGFRCG and eGFRMDRD overestimated mCLCR across the entire range of GFR. In critically ill patients, dose adjustments of 24 h-CI meropenem should be based on mCLCR. Equations for estimation of GFR may lead to gross under/overestimates of meropenem dosages. TDM may be highly beneficial, especially for critically ill patients with augmented renal clearance.

The new, race-free, Chronic Kidney Disease Epidemiology Consortium (CKD-EPI) equation to estimate glomerular filtration rate: is it applicable in Europe? A position statement by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM).

The EFLM recommends not to implement the race-free Chronic Kidney Disease Epidemiology Consortium (CKD-EPI) equation in European laboratories and to keep the 2009 version of the CKD-EPI equation, without applying a race correction factor. This recommendation is completely in line with a recent Editorial published by the European Renal Association who has also proposed to change to a novel equation only when it has considerably better performance, trying to reach global consensus before implementing such a new glomerular filtration rate (GFR) estimation equation. In Europe, this equation could be for instance the new European Kidney Function Consortium (EKFC) equation, which is population-specific, developed from European cohorts and accurate from infants to the older old. Beyond serum creatinine, the estimating equations based on cystatin C will probably gain in popularity, especially because cystatin C seems independent of race. Finally, we must keep in mind that all GFR equations remain an estimation of GFR, especially rough at the individual level. Measuring GFR with a reference method, such as iohexol clearance, remains indicated in specific patients and/or specific situations, and here also, the role of the clinical laboratories is central and should still evolve positively in the future.

GFR Estimation in Potential Living Kidney Donors: Race- and Nonrace-based Equations and Measured GFR

Recent studies evaluated and proposed new race-neutral, creatinine-based glomerular filtration rate (GFR) estimation equations. The performance of these equations in diverse potential living kidney donors requires study. Cross-sectional study. 637 potential living kidney donors from one tertiary hospital with serum creatinine concentration measurement and GFR measurement by iohexol plasma clearance between October 2016 and December 2020. Creatinine-based estimation of GFR by Chronic Kidney Disease Epidemiology Collaboration (2009, CKDEPI09; 2021, CKDEPI21) and Modification of Diet in Renal Disease equations with and without inclusion of race coefficient, where applicable. Equation bias, precision, accuracy, and accurate classification of GFR as equal to and above or below 80mL/min/1.73m2. GFR estimation equation performance compared to measured GFR (mGFR) by iohexol clearance. The median bias of the CKDEPI21 equation underestimated mGFR by 2.8mL/min/1.73m2. The bias in the Black subgroup underestimated mGFR by 9.0mL/min/1.73m2. Compared to CKDEPI09 with and without race adjustment, the accuracy of CKDEPI21 increased across all subgroups. On average, 3.9% of individuals were misclassified by CKDEPI21 as having a GFR greater than, and 8.9% misclassified less than, 80mL/min/1.73m2, compared to 3.1% and 13.2% for CKDEPI09 with race adjustment, respectively. Total misclassification (either above or below 80mL/min/1.73m2) was 16.3% for CKDEPI21 and 16.0% for CKDEPI09 (with race adjustment). Limited sample of individuals identifying as Black. Lack of cystatin C data. In our potential living donor sample, GFR estimation by creatinine-based CKDEPI21 is less biased and more accurate than previous creatinine-based estimated GFR equations. When evaluated by race, this summative improvement remains in individuals identifying as Asian, Hispanic, or White. More external validation is needed to assess whether the new equation is an improvement over the previous CKDEPI equation with a race coefficient.

An Endorsement of the Removal of Race From GFR Estimation Equations: A Position Statement From the National Kidney Foundation Kidney Disease Outcomes Quality Initiative

An Endorsement of the Removal of Race From GFR Estimation Equations: A Position Statement From the National Kidney Foundation Kidney Disease Outcomes Quality Initiative

Construct a classification decision tree model to select the optimal equation for estimating glomerular filtration rate and estimate it more accurately

Chronic kidney disease (CKD) has become a worldwide public health problem and accurate assessment of renal function in CKD patients is important for the treatment. Although the glomerular filtration rate (GFR) can accurately evaluate the renal function, the procedure of measurement is complicated. Therefore, endogenous markers are often chosen to estimate GFR indirectly. However, the accuracy of the equations for estimating GFR is not optimistic. To estimate GFR more precisely, we constructed a classification decision tree model to select the most befitting GFR estimation equation for CKD patients. By searching the HIS system of the First Affiliated Hospital of Zhejiang Chinese Medicine University for all CKD patients who visited the hospital from December 1, 2018 to December 1, 2021 and underwent Gate’s method of 99mTc-DTPA renal dynamic imaging to detect GFR, we eventually collected 518 eligible subjects, who were randomly divided into a training set (70%, 362) and a test set (30%, 156). Then, we used the training set data to build a classification decision tree model that would choose the most accurate equation from the four equations of BIS-2, CKD-EPI(CysC), CKD-EPI(Cr-CysC) and Ruijin, and the equation was selected by the model to estimate GFR. Next, we utilized the test set data to verify our tree model, and compared the GFR estimated by the tree model with other 13 equations. Root Mean Square Error (RMSE), Mean Absolute Error (MAE) and Bland–Altman plot were used to evaluate the accuracy of the estimates by different methods. A classification decision tree model, including BSA, BMI, 24-hour Urine protein quantity, diabetic nephropathy, age and RASi, was eventually retrieved. In the test set, the RMSE and MAE of GFR estimated by the classification decision tree model were 12.2 and 8.5 respectively, which were lower than other GFR estimation equations. According to Bland–Altman plot of patients in the test set, the eGFR was calculated based on this model and had the smallest degree of variation. We applied the classification decision tree model to select an appropriate GFR estimation equation for CKD patients, and the final GFR estimation was based on the model selection results, which provided us with greater accuracy in GFR estimation.

The race coefficient in glomerular filtration rate-estimating equations and its removal.

To review new publications about the use of the race coefficient in glomerular filtration rate (GFR)-estimating equations since this topic was last reviewed a year ago in Current Opinion in Nephrology and Hypertension . Accounting for race (or genetic ancestry) does improve the performance of GFR-estimating equations when serum creatinine (SCr) is used as the filtration marker but not when cystatin C is used. The National Kidney Foundation (NKF)-American Society of Nephrology (ASN) Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease recommended immediate adoption of a new refitted SCr-based equation without race and increased use of cystatin C. This report has created consensus but the endorsed new SCr equation without race underestimates GFR in Black Americans and overestimates GFR in non-Black Americans, which may result in diminished ability to detect racial disparities. The approach recommended by the NKF-ASN Task Force represents a compromise attempting to balance a number of competing values, including racial justice, benefit of classifying more Black Americans as having (more severe) chronic kidney disease, accuracy compared with measured GFR, and financial cost. The full implications of adopting the race-free refitted CKD-EPI SCr equation are yet to be known.

Performance of the 2021 Race-Free CKD-EPI Creatinine- and Cystatin C–Based Estimated GFR Equations Among Kidney Transplant Recipients

Race-free estimated glomerular filtration rate (eGFR) equations incorporating creatinine with and without cystatin C were recently developed and recommended for routine use. However, the performance of these equations among kidney transplant recipients (KTRs) remains unknown. Cross-sectional study to validate the 2021 race-free Chronic Kidney Disease (CKD) Epidemiology Collaboration (CKD-EPI) eGFR equation based on creatinine alone (eGFRcr) or based on creatinine and cystatin C (eGFRcr-cys) among KTRs. KTRs in stable condition (N= 415) from Canada and New Zealand with same-day measurements of creatinine, cystatin C, and glomerular filtration rate (GFR) usingradiolabeled diethylenetriaminepentaacetic acid. The 2009 CKD-EPI eGFRcr, 2021 CKD-EPI eGFRcr, 2012 CKD-EPI eGFRcr-cys, 2021 CKD-EPI eGFRcr-cys, 2012 CKD-EPI eGFRcys, and Modification of Diet in Renal Disease (MDRD) Study eGFR equations were compared with measured GFR. Bias, precision, accuracy, and correct classification by CKD stage. Bias was defined as the difference between estimated and measured GFR. Precision was represented by the interquartile range. Accuracy was defined as the percentages of participants with eGFRs within 10%/20%/30% (P10/P20/P30) of measured GFR, root mean square error, and mean absolute error. 87% of patients studied were White, 3% Black, and 10% other races. Mean measured GFR was 53 ± 19 (SD) mL/min/1.73 m2. The 2009 and 2021 CKD-EPI eGFRcr equations demonstrated similar median bias (-2.3 vs-0.2 mL/min/1.73 m2, respectively), precision (14.5 vs 14.9 mL/min/1.73 m2), and accuracy (P10/P20/P30, 32%/65%/84% vs 33%/63%/84%). The 2012 and 2021 CKD-EPI eGFRcr-cys equations also demonstrated similar median bias (-3.6 vs 0.3 mL/min/1.73 m2, respectively), precision (13.3 vs 14.3 mL/min/1.73 m2), and accuracy (P10/P20/P30, 32%/63%/80% vs 32%/67%/83%). No clear difference in performance was detected between the 2021 CKD-EPI eGFRcr and eGFRcr-cys equations among KTRs. The proportion of correct classification by CKD stage was similar across all eGFR equations. Moderate sample size, few patients had a GFR<30 mL/min/1.73 m2, and the large majority of patients were White. Among KTRs, the 2021 race-free CKD-EPI eGFR equations perform similarly to the previous CKD-EPI equations that included race correction terms. No significant difference in performance was observed between the 2021 CKD-EPI eGFRcr and eGFRcr-cys equations in the kidney transplant population.

Improved equations to estimate GFR in Chinese children with chronic kidney disease.

There is currently no specific equation for estimating glomerular filtration rate (GFR) in Chinese children with chronic kidney disease (CKD). The commonly used equations are less robust than expected; we therefore sought to derive more appropriate equations for GFR estimation. A total of 751 Chinese children with CKD were divided into 2 groups, training group (n = 501) and validation group (n = 250). In the training group, a univariate linear regression model was used to calculate predictability of variables associated with GFR. Residuals were compared to determine multivariate predictability of GFR in the equation. Standard regression techniques for Gaussian data were used to determine coefficients of GFR-estimating equations after logarithmic transformation of measured GFR (iGFR), height/serum creatinine (height/Scr), cystatin C, blood urea nitrogen (BUN), and height. These were compared with other well-known equations using the validation group. Median 99mTc-DTPA GFR was 90.1 (interquartile range: 67.3-108.6) mL/min/1.73 m2 in training dataset. Our CKD equation, eGFR (mL/min/1.73 m2) = 91.021 [height(m)/Scr(mg/dL)/2.7]0.443 [1.2/Cystatin C(mg/L)]0.335 [13.7/BUN (mg/dL)]-0.095 [ 0.991male] [height(m)/1.4]0.275, was derived. This was further tested in the validation group, with percentages of eGFR values within 30% and 15% of iGFR (P30 and P15) of 76.00% and 48.40%, respectively. For centres with no access to cystatin C, a creatinine-based equation, eGFR (mL/min/1.73 m2) = 89.674 [height(m)/Scr(mg/dL)/2.7]0.579 [ 1.007male] [height(m)/1.4]0.187, was derived, with P30 and P15 73.60% and 49.20%, respectively. These were significantly higher compared to other well-known equations (p < 0.05). We developed equations for GFR estimation in Chinese children with CKD based on Scr, BUN and cystatin C. These are more accurate than commonly used equations in this population.

Comparison of creatinine-based glomerular filtration rate estimation equations in voluntary Indian kidney donors: A single centre study

Introduction: In transplantation, accurate estimation of the donor glomerular filtration rate (GFR) is crucial. While various creatinine-based equations are in use, none are validated in Indians. Objectives: This study was conducted to judge the accuracy of creatinine-based GFR estimation equations and urinary creatinine clearance. Patients and Methods: A single-centre, observational and retrospective study at a tertiary care hospital. Adult voluntary donors GFR measured (mGFR) by technetium-99m diethylenetriaminepentaacetic acid (Tc-99m DTPA) were included. The primary outcome was the performance of estimated GFR (eGFR) by "Cockcroft-Gault’s formula corrected for body surface area (CG-BSA) formula", "modification of diet in renal disease (MDRD) 4 and 6 variable equation" and "Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation"; secondary outcome was the performance of "24-hour urinary creatinine clearance (Cr Cl)". Results: 102 kidney donors were analysed with mean age of 45.89 ± 9.98 years and 85.3% females. Mean ± SD mGFR by Tc-99m DTPA was 82.11 ± 14.32 mL/min/1.73 m2 . Mean ± SD eGFR by "CGBSA" was 99.68 ± 23.71 mL/min/1.73 m2 , by "MDRD-4 variable equation" was 98.25 ± 28.61 mL/ min/1.73 m2 , by "MDRD-6 variable equation" was 93.66 ± 19.44 ml/min/1.73 m2 and by "CKD-EPI" was 111.14 ± 31.61 mL/min/1.73 m2 . The lowest bias (2.3), highest precision (16.23), and accuracy (97.1%) were with "MDRD-6 variable equation"; "24-hour urinary Cr Cl" highly overestimated GFR (158.27 mL/min/1.73 m2 ) with the highest bias, lowest precision, and accuracy. Conclusion: The "MDRD-6 variable equation" was the most precise and accurate of the equations, whereas "24-hour urinary Cr Cl" was the least dependable. This study highlights the need for a correction factor or a new GFR estimation equation and not to consider urinary Cr Cl to assess donor GFR.

Evaluation of novel glomerular filtration rate estimation equations in adolescents and young adults with type 1 diabetes

AimsIndividuals with type 1 diabetes (T1D) are at an increased risk of chronic kidney disease making estimation of glomerular filtration rate (eGFR) an important component of diabetes care. Which eGFR equation is most appropriate to use in patients with T1D during the transition to adult care is unclear. We, therefore, sought to evaluate the performance of five eGFR equations in adolescents and young adults with T1D. MethodsMeasured iohexol-based glomerular filtration rate was compared to the Chronic Kidney Disease and Epidemiology Collaboration (CKD-EPI) eGFR, Chronic Kidney Disease in Children (CKiD) eGFR, and three recently developed age-adjusted versions of these in 53 patients with T1D and preserved GFR using bias, precision, and accuracy. ResultsThe best performance was found in the sex-dependent CKiD equation (bias: −0.8, accuracy: 11.8 ml/min/1.73 m2). Bias and accuracy (26.4 and 26.8 ml/min/1.73 m2) were worst in the CKD-EPI equation. Age-dependent adjustment improved performance for this equation (bias: 5.3, accuracy: 13.4 ml/min/1.73 m2), but not for the CKiD equation (bias: 15.5, accuracy: 18.8 ml/min/1.73 m2). ConclusionAge-adjustment improved performance for the CKD-EPI equation, but not for the CKiD equation. The sex-adjusted CKiD equation performed best out of all equations.

EGFR and chemotherapy: will removing race create disparities?

Assessment of glomerular filtration rate (GFR) is necessary for determining eligibility and dosing of chemotherapeutic agents that are excreted by the kidney. Measured GFR (mGFR), determined from filtration marker clearance, is infrequent in clinical practice; instead, current guidelines recommend estimated GFR (eGFR) from serum creatinine (eGFRCr) in adults using the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) 2009 equation, which includes age, sex, and race. 1 Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work GroupKDIGO 2012 clinical practice guideline for the evaluation and management of chronic kidney disease. Kidney Int Suppl. 2012; 3: 1-150 Google Scholar As part of a broader movement to avoid potential racial bias in clinical algorithms, the US National Kidney Foundation and American Society of Nephrology have established a task force to consider removing race from GFR-estimating equations. 2 Delgado C Baweja M Burrows NR et al. Reassessing the inclusion of race in diagnosing kidney diseases: an interim report from the NKF-ASN task force. Am J Kidney Dis. 2021; 1: 103-115 Summary Full Text Full Text PDF Scopus (15) Google Scholar Several methods could be used; one commonly used method is to assign the non-Black eGFR value to Black patients. 3 Powe NR Black kidney function matters: use or misuse of race?. JAMA. 2020; 324: 737-738 Crossref PubMed Scopus (46) Google Scholar The effects on eGFR are easy to compute, but the effects on clinical practice have not yet been carefully studied. In The Lancet Oncology, Morgan Casal and colleagues 4 Casal MA Ivy SP Beumer JH Nolin TD Effect of removing race from glomerular filtration rate-estimating equations on anticancer drug dosing and eligibility: a retrospective analysis of National Cancer Institute phase 1 clinical trial participants. Lancet Oncol. 2021; (published online Aug 13.)https://doi.org/10.1016/S1470-2045(21)00377-6 Summary Full Text Full Text PDF PubMed Scopus (3) Google Scholar report the simulated effects of removing race from the CKD-EPI equation on eligibility and recommended dosage adjustments for ten chemotherapeutic agents for Black patients with cancer. Effect of removing race from glomerular filtration rate-estimating equations on anticancer drug dosing and eligibility: a retrospective analysis of National Cancer Institute phase 1 clinical trial participantsRemoving race from the CKD-EPI equation will calculate a lower eGFR for Black patients and exclude more patients from receiving anticancer therapy, which could lead to undertreatment of Black patients with cancer and adversely affect their outcomes. Full-Text PDF

Effect of removing race from glomerular filtration rate-estimating equations on anticancer drug dosing and eligibility: a retrospective analysis of National Cancer Institute phase 1 clinical trial participants.

Kidney function assessment by estimated glomerular filtration rate (eGFR) equations, such as the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation, is important to determine dosing and eligibility for anticancer drugs. Inclusion of race in eGFR equations calculates a higher eGFR at a given serum creatinine concentration for Black patients versus non-Black patients. We aimed to characterise the effect of removing race from the CKD-EPI equation on dosing and eligibility of anticancer drugs with kidney function cutoffs. We did a retrospective analysis of patients enrolled in phase 1 studies sponsored by the Cancer Therapy Evaluation Program between January, 1995, and October, 2010. eGFR based on creatinine (eGFRCr) was calculated by the CKD-EPI equation and a version of the CKD-EPI equation without the race term (CKD-EPIwithout race). Estimated creatinine clearance (eClCr) was calculated by the Cockcroft-Gault equation. Dosing simulations based on each assessment of kidney function were done for ten anticancer drugs with kidney function cutoffs for dosing (oxaliplatin, capecitabine, etoposide, topotecan, fludarabine, and bleomycin) or eligibility (cisplatin, pemetrexed, bendamustine, and mitomycin) based on labelling approved by the US Food and Drug Administration or consensus guidelines. The absolute proportion of patients eligible or in each renal dosing range was calculated for each drug. Eligibility and dosing discordance rates were also calculated. Demographics and laboratory values from 340 Black patients (172 men and 168 women) were used. Median age was 57 years (IQR 47-64), median bodyweight was 78·1 kg (67·0-89·8), median body surface area was 1·91 m2 (1·77-2·09), and median serum creatinine concentration was 0·9 mg/dL (0·8-1·1). Median eGFRCr or eClCr was 103 mL/min (85-122) calculated by CKD-EPI, 89 mL/min (73-105) by CKD-EPIwithout race, and 90 mL/min (72-120) by Cockcroft-Gault. Black patients were recommended to receive dose reductions or were rendered ineligible to receive drug more frequently when using CKD-EPIwithout race than when using CKD-EPI, but at a similar rate as when using Cockcroft-Gault. The number of patients ineligible for therapy or recommended to receive any renal dose adjustment when CKD-EPIwithout race versus CKD-EPI was used increased by 72% (from 25 of 340 to 43 of 340 patients) for cisplatin, by 120% (from five to 11) for pemetrexed, by 67% (from three to five) for bendamustine, by 150% (from ten to 25) for capecitabine, by 150% (from ten to 25) for etoposide, by 67% (from three to five) for topotecan, by 61% (from 74 to 119) for fludarabine, and by 163% (from eight to 21) for bleomycin. Up to 18% of patients had discordant recommendations using CKD-EPIwithout race versus CKD-EPI. Removing race from the CKD-EPI equation will calculate a lower eGFR for Black patients and exclude more patients from receiving anticancer therapy, which could lead to undertreatment of Black patients with cancer and adversely affect their outcomes. National Institutes of Health.