Filtration Rate Estimation Equations Research Articles

Evaluation of Race-Neutral Glomerular Filtration Rate Estimating Equations in an Indian Population

Glomerular filtration rate (GFR) estimation equations have not been extensively validated in the Indian population. Preliminary data showed that the widely used creatinine-based Chronic Kidney Disease Epidemiology Collaboration (CKD-EPICr) 2009 significantly overestimated GFR in Indians. Newer estimated GFR (eGFR) equations based on creatinine and cystatin C, omitting the race, have been recently proposed. We investigated the performance of race-free eGFR equations in the Indian population. Patients with chronic kidney disease (CKD) and potential kidney donors attending the outpatient clinic at the Postgraduate Institute of Medical Education and Research Chandigarh, India, were screened for enrolment. GFR was measured by urinary clearance of inulin and plasma clearance of iohexol. Performance of eGFR equations (CKD-EPICr(2021), CKD-EPICr-Cys(2021), CKD-EPICr(2009), CKD-EPICr-Cys(2012), CKD-EPICys, 2020Csy-B2M-BTP and 2020Cr-Csy-B2M-BTP, EKFCcr, EKFCcys, and EKFCcr-cys) were assessed against measured GFR (mGFR) using bias, precision, and accuracy (root mean square error [RMSE], mean absolute error [MAE] and P30 [% with eGFR within 30% of mGFR]). A total of 412 subjects (55% with CKD), average age 47 ± 11 years with an equal distribution of males and females were enrolled. The mean mGFR in the study population was 54.2 ± 30.2 ml/min per 1.73 m2. The average mGFR in the potential kidney donor's subgroup was 79.5 ± 23.2 ml/min per 1.73 m2. Bias was highest for creatinine-based eGFR equations (CKD-EPIcr(2021):-19.2 [-21.3 to-17.0] ml/min per 1.73 m2and CKD-EPIcr(2009):-17.0 [-19.1 to-15.0] ml/min per 1.73 m2). Cystatin C- (either alone or with other markers) based equations were slightly better but still did not reach P30≥ 80%. Race-neutral CKD-EPICr(2021) equation did not significantly improve performance as compared to CKD-EPICr(2009) equation. These observations emphasize the need for developing new eGFR equations for Indians and to standardize the mGFR for easy access to care providers for individualized patient care.

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...

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

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.

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.

GFR Estimation After Cystatin C Reference Material Change

IntroductionGlomerular filtration rate (GFR) is routinely estimated with cystatin C. In June 2010, the International Federation of Clinical Chemistry (IFCC) released a certified cystatin C reference material (ERM-DA471/IFCC), and new cystatin C glomerular filtration rate estimation (eGFR) equations were developed with the IFCC standard. Early in 2018, Siemens discontinued their nonstandardized cystatin C reagent kits and replaced them with IFCC-calibrated kits in the US market. The aim of the current study was to assess the effect of IFCC calibration on cystatin C values and corresponding GFR estimations.MethodsCystatin C concentration was measured in 81 pediatric patients using a plasma sample from their nuclear GFR measurement with 99mTc-diethylenetriaminepentaaccetic acid. Calibration curves were generated using Siemens nonstandardized and IFCC-standardized kits to measure paired cystatin C concentrations in each sample. GFR-estimating equations using pre-IFCC and IFCC cystatin C values were compared using Bland-Altman analyses.ResultsThe IFCC-standardized assay resulted in a mean increase in the measured cystatin C value of 24%. Estimating equations consistently overestimated GFR prior to IFCC standardization. Following incorporation of the IFCC standard, the Full Age Spectrum equation demonstrated the best overall performance, whereas the Chronic Kidney Disease in Children (CKiD) equation was more accurate in children with decreased GFR.ConclusionIncorporation of the IFCC standard significantly increased cystatin C values and affected the performance of GFR estimating equations. Clinical laboratories and providers may need to update the equation used for cystatin C–based estimation of GFR following adoption of the IFCC reference standard.

Improving accuracy of estimating glomerular filtration rate using artificial neural network: model development and validation

BackgroundThe performance of previously published glomerular filtration rate (GFR) estimation equations degrades when directly used in Chinese population. We incorporated more independent variables and using complicated non-linear modeling technology (artificial neural network, ANN) to develop a more accurate GFR estimation model for Chinese population.MethodsThe enrolled participants came from the Third Affiliated Hospital of Sun Yat-sen University, China from Jan 2012 to Jun 2016. Participants with age < 18, unstable kidney function, taking trimethoprim or cimetidine, or receiving dialysis were excluded. Among the finally enrolled 1952 participants, 1075 participants (55.07%) from Jan 2012 to Dec 2014 were assigned as the development data whereas 877 participants (44.93%) from Jan 2015 to Jun 2016 as the internal validation data. We in total developed 3 GFR estimation models: a 4-variable revised CKD-EPI (chronic kidney disease epidemiology collaboration) equation (standardized serum creatinine and cystatin C, age and gender), a 9-variable revised CKD-EPI equation (additional auxiliary variables: body mass index, blood urea nitrogen, albumin, uric acid and hemoglobin), and a 9-variable ANN model.ResultsCompared with the 4-variable equation, the 9-variable equation could not achieve superior performance in the internal validation data (mean of difference: 5.00 [3.82, 6.54] vs 4.67 [3.55, 5.90], P = 0.5; interquartile range (IQR) of difference: 18.91 [17.43, 20.48] vs 20.11 [18.46, 21.80], P = 0.05; P30: 76.6% [73.7%, 79.5%] vs 75.8% [72.9%, 78.6%], P = 0.4), but the 9-variable ANN model significantly improve bias and P30 accuracy (mean of difference: 2.77 [1.82, 4.10], P = 0.007; IQR: 19.33 [17.77, 21.17], P = 0.3; P30: 80.0% [77.4%, 82.7%], P < 0.001).ConclusionsIt is suggested that using complicated non-linear models like ANN could fully utilize the predictive ability of the independent variables, and then finally achieve a superior GFR estimation model.

Improvement of renal function estimation equations for elderly Japanese people.

Background and aimThe Cockcroft‐Gault (C‐G) equation for estimation of creatinine clearance (CCr) is still used in a clinical setting for drug dosage adjustment. Because differences between measured and estimated CCr values have been reported, particularly for Japanese elderly people, the aim of this study was to improve the accuracy of CCr estimation equations, such as C‐G and Orita‐Horio, by fitting to newly obtained data. Also, glomerular filtration rate (GFR) estimation equations, such as the Modification of Diet in Renal Disease (MDRD), the Chronic Kidney Disease Epidemiology Collaboration (CKD‐EPI), and the eGFR equation for Japanese people, were studied to compare with measured CCr.MethodData from 313 subjects over the age of 40 years with laboratory data available were used for analysis in this study. Special attention was paid to elderly people, and approximately 70% of the subjects were over the age of 65 years.ResultsThe accuracy of estimation by the two conventional (C‐G, Orita‐Horio) CCr estimation equations was greatly improved by introducing adjusted body weight for which the degree of obesity is over 30% instead of measured body weight. By fitting the coefficients of the estimation equations to the present population, the mean error was reduced by almost half, particularly for people over the age of 75. Although all the values calculated by the GFR estimation equations were underestimated compared with measured CCr due to secretion, a coefficient of determination of above 0.65 was obtained for all GFR estimation equations.ConclusionsImprovement of the fitted CCr estimation equations suggests that reconstruction of renal function estimation equations is required, especially for old people. Further work is required to find optimal renal function (CCr and/or GFR) estimation equations for drug dosage adjustment.

Performance of glomerular filtration rate estimation equations in Congolese healthy adults: The inopportunity of the ethnic correction.

Context and objectiveIn the estimation of glomerular filtration rate (GFR), ethnicity is an important determinant. However, all existing equations have been built solely from Caucasian and Afro-American populations and they are potentially inaccurate for estimating GFR in African populations. We therefore evaluated the performance of different estimated GFR (eGFR) equations in predicting measured GFR (mGFR).MethodsIn a cross-sectional study, 93 healthy adults were randomly selected in the general population of Kinshasa, Democratic Republic of the Congo, between June 2015 and April 2016. We compared mGFR by plasma clearance of iohexol with eGFR obtained with the Modified Diet in Renal Disease (MDRD) equation with and without ethnic factor, the Chronic Kidney Disease Epidemiology (CKD-EPI) serum creatinine (SCr)-based equation, with and without ethnic factor, the cystatin C-based CKD-EPI equation (CKD-EPI SCys) and with the combined equation (CKD-EPI SCrCys) with and without ethnic factor. The performance of the equations was studied by calculating bias, precision and accuracy within 30% (P30) of mGFR.ResultsThere were 48 women and 45 men. Their mean age was 45.0±15.7 years and the average body surface area was 1.68±0.16m2. Mean mGFR was 92.0±17.2 mL/min/1.73m2 (range of 57 to 141 mL/min/1.73m2). Mean eGFRs with the different equations were 105.5±30.1 and 87.2±24.8 mL/min/1.73m2 for MDRD with and without ethnic factor, respectively; 108.8±24.1 and 94.3x20.9 mL/min/1.73m2 for CKD-EPI SCr with and without ethnic factor, respectively, 93.5±18.6 mL/min/1.73m2 for CKD-EPI SCys; 93.5±18.0 and 101±19.6 mL/min/ 1.73m2 for CKD-EPI SCrCys with and without ethnic factor, respectively. All equations slightly overestimated mGFR except MDRD without ethnic factor which underestimated by -3.8±23.0 mL/min /1.73m2. Both CKD-EPI SCr and MDRD with ethnic factors highly overestimated mGFR with a bias of 17.9±19.2 and 14.5±27.1 mL/min/1.73m2, respectively. There was a trend for better P30 for MDRD and CKD-EPI SCr without than with the ethnic factor [86.0% versus 79.6% for MDRD (p = 0.21) and 81.7% versus 73.1% for the CKD-EPI SCr equations (p = 0.057)]. CKD-EPI SCrCys and CKD-EPI SCys were more effective than creatinine-based equations.ConclusionIn the Congolese healthy population, MDRD and CKD-EPI equations without ethnic factors had better performance than the same equations with ethnic factor. The equations using Cys C (alone or combined with SCr) performed better than the creatinine-based equations.

MDRD or CKD-EPI for glomerular filtration rate estimation in living kidney donors

IntroductionThe evaluation of the measured Glomerular Filtration Rate (mGFR) or estimated Glomerular Filtration Rate (eGFR) is key in the proper assessment of the renal function of potential kidney donors. We aim to study the correlation between glomerular filtration rate estimation equations and the measured methods for determining renal function. Material and methodsWe analyzed the relationship between baseline GFR values measured by Tc-99m-DTPA (diethylene-triamine-pentaacetate) and those estimated by the four-variable Modification of Diet in Renal Disease (MDRD4) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations in a series of living donors at our institution. ResultsWe included 64 donors (70.6% females; mean age 48.3±11 years). Baseline creatinine was 0.8±0.1mg/dl and it was 1.1±0.2mg/dl one year after donation. The equations underestimated GFR when measured by Tc99m-DTPA (MDRD4 – 9.4±25ml/min, P<.05, and CKD-EPI – 4.4±21ml/min). The correlation between estimation equations and the measured method was superior for CKD-EPI (r=.41; P<.004) than for MDRD4 (r=.27; P<.05). eGFR decreased to 59.6±11 (MDRD4) and 66.2±14ml/min (CKD-EPI) one year after donation. This means a mean eGFR reduction of 28.2±16.7ml/min (MDRD4) and 27.31±14.4ml/min (CKD-EPI) at one year. ConclusionsIn our experience, CKD-EPI is the equation that better correlates with mGFR-Tc99m-DTPA when assessing renal function for donor screening purposes.

Accuracy of glomerular filtration rate estimationequations in patients with hematopathy.

Renal dysfunction is a common side-effect of chemotherapeutic agents in patients with hematopathy. Although broadly used, glomerular filtration rate (GFR) estimation equations were not fully validated in this specific population. Thus, this study was designed to further assess the accuracy of various GFR equations, including the newly 2012 CKD-EPI equations. Referring to 99mTc-DTPA clearance method, three Scr-based (MDRD, Peking, and CKD-EPIScr), three Scys C-based (Steven 1, Steven 2, and CKD-EPIScys C), and three Scr-Scys C combination based (Ma, Steven 3, and CKD-EPIScr-Scys C) equations were included. Bias, P30, and misclassification rate were applied to compare the applicability of the selected equations. A total of 180 Chinese hematological patients were enrolled. Mean bias, absolute mean bias, P30, misclassification rate and Bland-Altman plots of the CKD-EPIScr-Scys C equation were 7.90 mL/minute/1.73 m2, 17.77 mL/minute/1.73 m2, 73.3%, 38% and 79.7 mL/minute/1.73 m2, respectively. CKD-EPIScr-Scys C predicted the most precise eGFR both in lymphoma and leukemia subgroups. Additionally, CKD-EPIScys C equation in the rGFR ≧ 90 mL/minute/1.73 m2 subgroup and Steven 2 equation in the rGFR<90 mL/minute/1.73 m2 subgroup provided more accurate estimates in each subgroup. The CKD-EPIScr-Scys C equation could be recommended to monitor kidney function in hematopathy patients. The accuracy of GFR equations may be closely related with GFR level and kidney function markers, but not the primary cause of hematopathy.

MDRD o CKD-EPI en la estimación del filtrado glomerular del donante renal vivo

IntroductionThe evaluation of the measured Glomerular Filtration Rate (mGFR) or estimated Glomerular Filtration Rate (eGFR) is key in the proper assessment of the renal function of potential kidney donors. We aim to study the correlation between glomerular filtration rate estimation equations and the measured methods for determining renal function. Material and methodsWe analysed the relationship between baseline GFR values measured by Tc-99m-DTPA (diethylene-triamine-pentaacetate) and those estimated by the four-variable Modification of Diet in Renal Disease (MDRD4) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations in a series of living donors at our institution. ResultsWe included 64 donors (70.6% females; mean age 48.3±11 years). Baseline creatinine was 0.8±0.1 mg/dl and it was 1.1±0.2 mg/dl one year after donation. The equations underestimated GFR when measured by Tc99m-DTPA (MDRD4–9.4 ± 25ml/min, P<.05, and CKD-EPI–4.4 ± 21ml/min). The correlation between estimation equations and the measured method was superior for CKD-EPI (r=.41; P<.004) than for MDRD4 (r=.27; P<.05). eGFR decreased to 59.6±11 (MDRD4) and 66.2±14ml/min (CKD-EPI) one year after donation. This means a mean eGFR reduction of 28.2±16.7 ml/min (MDRD4) and 27.31±14.4 ml/min (CKD-EPI) at one year. ConclusionsIn our experience, CKD-EPI is the equation that better correlates with mGFR-Tc99m-DTPA when assessing renal function for donor screening purposes.

Predictive performance of different kidney function estimation equations in lung transplant patients

BackgroundThere has been limited examination of the performance of glomerular filtration rate estimation (eGFR) equations in lung transplant populations. This study aimed to compare the performance of serum creatinine and cystatin C based eGFR equations with Tc-99m diethylenetriaminepentaacetic acid (DTPA) GFR measurements in individuals with end-stage lung disease, either prior to, or following, lung transplantation. MethodsIn this prospective observational study, participants underwent GFR measurements with Tc-99m Pentetate. Measured results were compared with GFR estimates derived from estimation equations [4-variable Modification of Diet in Renal Disease, Cockcroft-Gault, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine, cystatin C and creatinine-cystatin C combined equations]. ResultsNinety-seven individuals were studied (77 post- and 20 wait-listed for transplantation). Median (range) radionucleotide GFR was 56.7ml/min/1.73m2 (22.8–109.2ml/min/1.73m2). In the study cohort as a whole, the CKD-EPI creatinine-cystatin C combined equation showed the highest performance, but was only slightly superior to the CKD-EPI creatinine equation. However, in individuals with cystic fibrosis, low arm muscle mass and/or low body mass index, all of the creatinine-based equations showed unacceptable performance. In these subgroups, improved GFR estimation was seen with the CKD-EPI cystatin C equation, and predictions were better still using the CKD-EPI creatinine-cystatin C combined equation. ConclusionsThis study shows adequate predictive ability of CKD-EPI creatinine in the cohort as a whole, but unacceptable performance in patients with cystic fibrosis, low arm muscle mass and/or low body mass index. Our findings demonstrate that cystatin C may be a preferable filtration marker in these subgroups.

Cystatin C standardization decreases assay variation and improves assessment of glomerular filtration rate

BackgroundCystatin C is increasingly used in glomerular filtration rate (GFR) estimation equations. The dependence of cystatin C results upon the analytical method has been a major source of controversy. MethodsCystatin C was measured with non-standardized turbidimetric Roche Generation 1 and standardized nephelometric Siemens assays in 3666 and additionally with standardized Roche Generation 2 and Siemens in 567 blood samples of the Berlin Initiative Study. Cystatin C-based GFR was assessed with CKD-EPIcys (Chronic Kidney Disease Epidemiology) and CAPA (Caucasian, Asian, Pediatric, Adult) equations and the impact of the assays on GFR estimation was determined. Equation performance compared to measured GFR was evaluated. ResultsConcordance of Roche Gen2 and Siemens was high with median difference of 0.003±0.13mg/L (limits of agreement: −0.12 to 0.12) and Passing Bablok correlation was essentially perfect. Roche Gen1 assay showed worse concordance with Siemens: median difference was 0.08±0.13mg/L (limits of agreement: −0.18 to 0.34) and correlation was inferior. Mean difference (±SD) of estimated GFRCKD-EPIcys was 0±4mL/min/1.73m2 for Gen2 and Siemens compared to −5±8 with Gen1. Performance of GFR estimating equations was not influenced by the choice of Siemens or Gen2 assays. ConclusionsStandardization of Roche Gen2 assay improved accuracy of cystatin C measurement compared to Siemens. It suggests only negligible method bias and results in equal performance of both assays when estimating GFR indicating that successful calibration has led to major progress in cystatin C analysis.

Predictive performance of glomerular filtration rate estimation equations based on cystatin C versus serum creatinine values in critically ill patients

The predictive performance of glomerular filtration rate (GFR) estimation equations based on cystatin C versus serum creatinine (SCr) values in critically ill patients was evaluated. A retrospective observational study was performed in the medical intensive care unit (ICU) of a university hospital from October 2006 through September 2007. All consecutively admitted critically ill patients older than 18 years who stayed in the ICU for more than 48 hours with a urinary bladder catheter in place were included in the study. Data collected included SCr, cystatin C, serum albumin, blood urea nitrogen, and 24-hour urine creatinine clearance [Formula: see text] levels. The following equations were also used to determine the estimated GFR that was compared with the reference [Formula: see text] for all patients in the study: Arnal-Dade using cystatin C, Cockcroft-Gault using actual body weight, Cockcroft-Gault using ideal body weight, Jelliffe, Modification of Diet in Renal Disease (MDRD), and four-variable version MDRD (MDRD-4). This study included 241 measurements corresponding to 131 critically ill patients. The cystatin C-based equation underestimated [Formula: see text], whereas overestimation by every SCr-based formula was observed in the whole cohort and in the [Formula: see text] subgroup; MDRD-4 was the most biased equation in every analysis. There were no significant differences in precision, except for great variability in the subgroup with a [Formula: see text] of <60 mL/min/1.73 m(2), where the MDRD equation showed better results than the cystatin C-based equation (33.5% versus 38.9%). No equations fulfilled concordance requirements with [Formula: see text]. A retrospective observational study showed no evidence of superiority of a cystatin C-based equation over SCr-based equations to estimate the GFR in an ICU population.

Performance of three glomerular filtration rate estimation equations in a population of sub-Saharan Africans with Type 2 diabetes.

We evaluated the performance of the Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Cockcroft-Gault (CG) equations against creatinine clearance (CrCl) to estimate glomerular filtration rate (GFR) in 51 patients with Type 2 diabetes. The CrCl value was obtained from the average of two consecutive 24-h urine samples. Results were adjusted for body surface area using the Dubois formula. Serum creatinine was measured using the kinetic Jaffe method and was calibrated to standardized levels. Bland-Altman analysis and kappa statistic were used to examine agreement between measured and estimated GFR. Estimates of GFR from the CrCl, MDRD, CKD-EPI and CG equations were similar (overall P = 0.298), and MDRD (r = 0.58; 95% CI: 0.36-0.74), CKD-EPI (r = 0.55; 95% CI: 0.33-0.72) and CG (r = 0.61; 95% CI: 0.39-0.75) showed modest correlation with CrCl (all P < 0.001). Bias was -0.3 for MDRD, 1.7 for CKD-EPI and -5.4 for CG. All three equations showed fair-to-moderate agreement with CrCl (kappa: 0.38-0.51). The c-statistic for all three equations ranged between 0.75 and 0.77 with no significant difference (P = 0.639 for c-statistic comparison). The MDRD equation seems to have a modest advantage over CKD-EPI and CG in estimating GFR and detecting impaired renal function in sub-Saharan African patients with Type 2 diabetes. The overall relatively modest correlation with CrCl, however, suggests the need for context-specific estimators of GFR or context adaptation of existing estimators.

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Prognostic value of glomerular filtration rate estimation equations in acute heart failure with preserved versus reduced ejection fraction.

Renal function is an important prognostic factor in heart failure. The aim of this study was to compare the predictive value of estimated renal function calculated by the Chronic Kidney Disease-Epidemiology Collaboration equation (CKD-EPI) and the abbreviated Modification of Diet in Renal Disease (MDRD-4) equation for long-term all-cause mortality in patients admitted for acute decompensated heart failure (ADHF) with both preserved ejection fraction (HF-PEF) and reduced ejection fraction (HF-REF). We evaluated patients included in the Spanish National Registry of Heart Failure (RICA). RICA is a multicentre, prospective, cohort study that included patients admitted to the Internal Medicine units with ADHF. Estimated glomerular filtration rate (eGFR) was calculated with CKD-EPI and MDRD-4 equations. A total of 1805 patients admitted for ADHF were studied (52% women; median age 80years, interquartile range 73.9-84.6years); of these, 1044 (58%) had HF-PEF. eGFR values were lower with the CKD-EPI formula than with the MDRD-4 formula (51ml/min/1.73m(2) vs. 55.7ml/min/1.73m(2) ; p<0.001). The two formulas provided independent prognostic information over long-term follow-up, in both HF-PEF and HF-REF patients. However, in HF-PEF patients, CKD-EPI equation was associated with a significant improvement in reclassification analyses (net reclassification improvement 6.78%; p=0.009). In this clinical cohort of ADHF patients, eGFR as calculated by both the CKD-EPI and the MDRD-4 formulas offered similar prognostic information, irrespective of ejection fraction status, but in HF-PEF patients specifically, the CKD-EPI formula seems to improve clinical risk stratification as compared with MDRD-4.

Application of Modified Glomerular Filtration Rate Estimation Equations in Chinese Diabetic Patients with Chronic Kidney Diseases.

To evaluate the applicability of modified formulae based on plasma creatinine levels in Chinese diabetic patients with chronic kidney diseases (CKD). A total of 294 diabetic patients were investigated. Glomerular filtration rate (GFR) was estimated with the Ruijin equation, Cockcroft-Gault (CG) and Modification of Diet in Renal Disease (MDRD) formulae. The accuracy of estimated GFR was compared with technetium-99m diethylene triamine pentaacetic acid (99mTc-DTPA)-GFR (sGFR). Bland-Altman analysis demonstrated that the Ruijin equation was more consistent with sGFR than the other equations. However, all the equations were not very consistent with sGFR. The analysis showed that the slope of the Ruijin equation was closer to the identical line and indicated that the bias of Ruijin equation was lowest. The 15%, 30% and 50% accuracies of the Ruijin equation were higher than those of the other equations; the 30% accuracy of Ruijin equation was more than 70%. Ruijin equation is more applicable in Chinese diabetic and CKD patients.