Chronic Kidney Disease Stage Classification Research Articles

Comprehensive comparative evaluation of the eight pediatric estimated glomerular filtration rate equations in a large Korean pediatric patient cohort

IntroductionAlthough estimated glomerular filtration rate (eGFR) are continuously developed for pediatric population, impact of height measurement is often neglected due to variable dynamic growth changes in children. This study aimed to compare differential impacts of eGFR values calculated by six equations that do not use height information. Materials and methods3503 Korean pediatric patients with creatinine/cystatin C assay-based laboratory results from 2008 to 2021 were analyzed for clinical course using a total of 8113 laboratory test results. Baseline eGFR was calculated by eight different equations including two widely used equations incorporating height parameter. Along with the agreement of CKD (chronic kidney disease) stage categorization by different equations, clinical outcome of incident CKD diagnosis in 13 years of study period were compared. ResultsAmong a total of 28 pairwise comparisons among eight equations, only 4 combinations of comparisons revealed optimal P15 values (≥80 % concordance), with FAS-age equation being both concordant with two equations using height parameter. Clustering of eight equations by incident CKD diagnosis in subsequent tests also highlighted FAS-age as candidate equation within the same cluster with Schwartz-bedside and FAS-height equations. When the equation values were classified into Kidney Disease Improving Global Outcomes (KDIGO) CKD stages, the distribution patterns for stage 1 and 5 were significantly different among eGFR equations. FAS-age equation revealed the highest agreement with Schwartz-bedside and FAS-height equations that incorporate the height data. ConclusionsThe eGFR equation type should be considered to establish the eGFR intervals for CKD stage classification, particularly in the pediatric patient population. Cautious interpretation is required for eGFR value along with clinical context.

Patient-Reported Outcomes Measures, Polycystic Kidney Disease Burden, and Outcomes in Autosomal Dominant Polycystic Kidney Disease

Rationale & ObjectiveUsing OVERTURE (NCT01430494) study data on patient-perceived health, healthcare utilization, and productivity in autosomal dominant polycystic kidney disease (ADPKD), this research was conducted to characterize the burden of illness in ADPKD patients and assess whether patient-reported outcomes (PRO) assessment scores predict clinical and health-economic outcomes. Study DesignAnalyses of data from a prospective, observational study. Setting & ParticipantsThe study cohort comprised 3409 individuals with ADPKD in 20 countries, ages 12–78 years, in chronic kidney disease (CKD) stages G1–G5 and Mayo risk subclasses 1A–1E. PredictorsScores on PRO instruments, including disease-specific assessments (ADPKD-Impact Scale [ADPKD-IS], ADPKD-Urinary Impact Scale [ADPKD-UIS]) and generic measures. OutcomesClinical variables (e.g., height-adjusted total kidney volume [htTKV], estimated glomerular filtration rate [eGFR], abdominal girth) and health-economic outcomes. Analytical ApproachAssociations among variables were evaluated using Spearman correlations, logistic regression, and generalized linear mixed-effects repeated-measures models. ResultsBaseline CKD stage and Mayo risk classification showed little correlation with baseline PRO scores, although scores on disease-specific instruments and measures of physical functioning were worse at more severe CKD stages. PRO scores predicted hospitalizations and sick days at 6–18 months, with associations strongest for the ADPKD-IS. Whereas PRO scores were not associated with htTKV and eGFR, worse PRO scores were associated with greater abdominal girth. Poor baseline ADPKD-IS scores were positively associated with occurrence of ADPKD-related symptoms up to 18 months, including kidney pain (odds ratio [OR] 5.30, 95% confidence interval [CI] 2.75–10.24), hematuria (OR 4.58, 95% CI 1.99–10.53), and urinary tract infection (OR 4.41, 95% CI 1.93–10.11; P<0.001 for all). LimitationsMaximum 18 months of follow-up to assess outcomes. ConclusionsPRO scores predicted clinical and health-economic outcomes such as hospitalization and absence from work, underscoring the importance of quality of life assessment of individuals with ADPKD.

#3193 PERFORMANCE OF THE RACE-FREE CKD-EPI CREATININE-BASED EGFR EQUATION IN A DANISH COHORT WITH CHROMIUM-51-EDTA CLEARANCE MEASUREMENTS

Abstract Background and Aims In 2021, an updated estimated glomerular filtration rate (eGFR) equation based on serum creatinine, age, and sex, but without a coefficient for race (CKD-EPI21) was developed and recommended for clinical use. However, the performance of the new equation has yet to be examined among specific groups such as patients with cancer. Method We compared the performances of the CKD-EPI21 equation and the original creatinine-based eGFR equation assuming non-Black race (CKD-EPI09-NB) in patients ≥18 years of age with measured GFR ascertained by chromium-51-EDTA plasma clearance at Aarhus University Hospital in Denmark during 2010–2018. We examined bias, accuracy, precision (defined as the interquartile range of the absolute bias), and correct classification of chronic kidney disease (CKD) stages (GFR ≥60, 30–59, and &amp;lt;30 ml/min/1.73 m2) using the chromium-51-EDTA clearance as the reference standard. Furthermore, we assessed the performance of the equations in the total cohort while stratifying by CKD stage. We assessed the performance in the total cohort and in cohorts of cancer patients and potential living kidney donors. Results In this predominantly White population, the CKD-EPI21 equation performed slightly better than the CKD-EPI09-NB equation, both when examining the total cohort (N = 4,668) and when examining cohorts of cancer patients (N = 3,313) and potential living kidney donors (N = 239). In the total cohort, the CKD-EPI21 equation demonstrated lower median absolute bias (−0.2 versus −4.4 ml/min/1.73 m2), higher accuracy (72% versus 70%) as well as equal precision (25 versus 25 ml/min/1.73 m2) and correct classification of CKD stages (86% versus 85%) when compared with the CKD-EPI09-NB equation. When we stratified by CKD stage, the CKD-EPI09-NB equation performed slightly better than the CKD-EPI21 equation among patients with a GFR &amp;lt; 60 ml/min/1.73 m2. Conclusion In a selected cohort of Danish patients with measured GFR, the CKD-EPI21 equation performed slightly better than the CKD-EPI21-NB equation except for patients with a GFR &amp;lt; 60 ml/min/1.73 m2.

A Review on Machine Learning Approaches for HIV Infected Patient Chronic Kidney Disease Stage Classification

Chronic kidney disease (CKD) is sometimes called chronic kidney failure. The kidneys eliminate waste and surplus fluids from the circulation and excrete them as urine. In severe chronic renal disease, fluid, electrolytes, and waste products may build up in the body. HIV patients with additional risk factors for renal disease must have kidney function evaluated annually. HIV may damage kidney filters. The filters won't work properly. CKD has five stages, with more severe symptoms from stage 1 to stage 5. If chronic kidney disease continues to stage 4 or 5, our bodies might accumulate fluid and waste. Machine learning categories HIV-positive CKD patients based on their features. Machine learning relies on feature selection. This research uses feature selection and classification to accurately predict chronic renal illness.

Variability in Kidney Function Estimates in Emerging Adults With Spina Bifida: Implications for Transitioning From Pediatric to Adult Care

ObjectiveTo examine the variability of estimated glomerular filtration rate (eGFR) in emerging adults with spina bifida (SB) by comparing multiple equations across the transitional age period, hypothesizing that creatinine (Cr)-based equations show greater variability than cystatin-C (CysC)- or combination-based equations. MethodsA retrospective cohort study was performed from 2012 to 2017 at a multidisciplinary SB clinic. Emerging adults were defined as patients ages 18-28 years old. Four pediatric, 3 adult, and 3 averaged eGFR equations were considered. Cross-sectional variability in eGFR data was assessed using coefficients of variation, chronic kidney disease (CKD) stage classification, and pairwise percent relative difference in eGFR between analogous pediatric and adult equations based on included lab values. Longitudinal changes in eGFR over time were compared across equations using a covariance pattern model accounting for repeated measures. ResultsSeventy-five emerging adults with SB (median age 21.8 years; 55% female; 83% with myelomeningocele) were included in cross-sectional analyses. Adult equations gave higher median eGFRs by 22%-27% and generally milder CKD stage classification than analogous pediatric equations. In longitudinal analyses (median follow-up of 22 months), all equations conferred negative eGFR changes over time (range −1.9 to −4.3 mL/min/1.73m2 per year) that were not significantly different. ConclusionIn emerging adults with SB, adult equations demonstrated higher median eGFRs by 22%-27% compared to analogous pediatric equations, even with Cystatin-C, and generally downstaged CKD stage classification. The same eGFR equation should be used for serial kidney function monitoring in emerging adults with SB who transition care from pediatric to adult services.

Performance of StatSensor Point-of-Care Device for Measuring Creatinine in Patients With Chronic Kidney Disease and Postkidney Transplantation.

Background:The StatSensor is a point-of-care device which measures creatinine in capillary whole blood. Previous studies reported an underestimation of the creatinine measurements at high creatinine concentrations and were performed in the prestandardization era for creatinine.Objective:This accuracy-based study evaluates the use of this device in kidney-transplanted patients and those with chronic kidney disease (CKD).Design:Cross-sectional diagnostic accuracy study.Setting:Nephrology outpatient clinic in an urban tertiary center.Participants:Adults with CKD or a functioning kidney transplant.Measurements:Duplicate StatSensor creatinine measurements were performed on capillary whole blood samples collected by direct fingerstick and SAFE-T-FILL collection device. Results were compared with simultaneous venous blood sampling for serum and plasma creatinine measured by an enzymatic method on the Roche Integra 400 mainframe analyzer with traceability to the ID-GC-MS (isotope dilution gas chromatography mass spectrometry) reference method.Methods:Deming regression, Pearson correlation coefficient, and Bland-Altman analysis were used to assess accuracy and comparability between capillary whole blood measured by StatSensor and plasma creatinine measured by routine analyzer with traceability to the reference method. Estimated glomerular filtration (eGFR) rates were calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and concordance with Kidney Disease Improving Global Outcomes (KDIGO) CKD stage classification was evaluated.Results:There were 60 participants (mean age = 61.9 ± 15.0 years, 55% men, 33% transplant, mean plasma creatinine = 137 ± 59 µmol/L). Bland-Altman analysis indicated a positive mean bias of 12.7 µmol/L between StatSensor fingerstick creatinine measurement and plasma creatinine. Comparison of eGFR (CKD-EPI) calculated from the StatSensor fingerstick creatinine versus plasma creatinine showed misclassification across all KDIGO CKD stages. Postanalytical correction of the bias did not improve misclassifications. The use of mean of duplicate StatSensor creatinine results did not improve performance compared with the use of singlet results.Limitations:Single center, limited participant numbers.Conclusions:The results of our study suggest that the limiting characteristics of the StatSensor device are not only bias, but also imprecision. The level of imprecision observed may influence clinical decision-making and limit the usefulness of StatSensor as a CKD screening tool. If choosing to utilize it for either screening for or monitoring CKD, it is essential that clinicians understand the limitations of point-of-care devices and apply this knowledge to test interpretation.

Estimated kidney function in children and young adults with spina bifida: A retrospective cohort study.

Current estimated glomerular filtration rate (eGFR) equations may be inaccurate in patients with spina bifida (SB) because of reduced muscle mass and stature. Cross-sectional and longitudinal variability of eGFR were analyzed in these patients across multiple equations, hypothesizing greater variability in creatinine-based than cystatin-C (Cys-C)-based equations. This retrospective cohort study included children (age, 1-17.9 years) and adults (≥18 years) with SB from 2002-2017 at a large SB clinic. Those without all data needed to calculate eGFR were excluded. Four pediatric and three adult eGFR equations were compared for cross-sectional outcomes of eGFR and elevated office blood pressures using chronic kidney disease (CKD) stage classification, and for longitudinal outcome of eGFR slope over time using covariance pattern models accounting for repeated measures. One hundred and eighty two children and 75 adults had greater than or equal to 1 set of data measurements; 118 and 52, respectively, had greater than or equal to 2 sets. The pediatric bedside Schwartz equation had the highest median eGFR and coefficient of variation. CKD stage classification by eGFR showed large differences across equations in children, with rates of eGFR < 60 and <90 ml/min/1.73 m2 ranging from 2%-9% and 5%-69%, respectively. Only one equation showed a significant inverse association between eGFR and blood pressure. Longitudinally, eGFR slopes over time were different across pediatric equations (P < .001) but not adult equations. The bedside Schwartz equation had a positive eGFR slope; the other Cys-C-containing equations had negative slopes. Creatinine-based equations in children with SB vary considerably from cystatin-C-containing equations in calculating both single point-in-time eGFR values and eGFR trends over time.

Chronic kidney disease staging with cystatin C or creatinine-based formulas: flipping the coin.

Chronic kidney disease (CKD) affects 10-13% of the population worldwide. CKD classification stratifies patients in five stages of risk for progressive renal disease based on estimated glomerular filtration rate (eGFR) by formulas and albuminuria. However, the reliability of formulas to reflect real renal function is a matter of debate. The effect of the error of formulas in the CKD classification is unclear, particularly for cystatin C-based equations. We evaluated the reliability of a large number of cystatin C and/or creatinine-based formulas in the definition of the stages of CKD in 882 subjects with different clinical situations over a wide range of glomerular filtration rates (GFRs) (4.2-173.7 mL/min). Misclassification was a constant for all 61 formulas evaluated and averaged 50% for creatinine-based and 35% for cystatin C-based equations. Most of the cases were misclassified as one stage higher or lower. However, in 10% of the subjects, one stage was skipped and patients were classified two stages above or below their real stage. No clinically relevant improvement was observed with cystatin C-based formulas compared with those based on creatinine. The error in the classification of CKD stages by formulas was extremely common. Our study questions the reliability of both cystatin C and creatinine-based formulas to correctly classify CKD stages. Thus the correct classification of CKD stages based on estimated GFR is a matter of chance. This is a strong limitation in evaluating the severity of renal disease, the risk for progression and the evolution of renal dysfunction over time.

The Relevance of High Pulse Pressure and Renal Function in Patients with Chronic Kidney Disease: Analysis for each Stage of Chronic Kidney Disease

Background: In our previous study, we showed that high pulse pressure (PP) is associated with decreased renal function in chronic kidney disease (CKD) patients. In recent years, there were a few reports that CKD stage classification focused on glomerular filtration rate, which is associated with the occurrence of cardiovascular disease, deterioration of renal prognosis, and life prognosis. We aim to examine the relationship between increased PP and renal function according to each CKD stage classification. Methods: The present study includes 104 participants with CKD (stage G3a-G5) who visited the Nephrology Medicine Department of Yokosuka Kyousai Hospital between September 2006 and October 2011. The participants were categorized on the basis of PP: ≥65 mmHg was the High PP group, and

Evaluation of various equations for estimating renal function in elderly Chinese patients with type 2 diabetes mellitus.

BackgroundThe clinical assessment of kidney function based on the estimated glomerular filtration rate (GFR) in older patients remains controversial. This study evaluated the concordance and feasibility of using various creatinine-based equations for estimating GFR in elderly Chinese patients with type 2 diabetes mellitus (T2DM).MethodsA cross-sectional analytical study was conducted in 21,723 older diabetic patients (≥60 years) based on electronic health records (EHR) for Minhang District, Shanghai, China. The concordance of chronic kidney disease (CKD) classification among different creatinine-based equations was assessed based on Kappa values, intraclass correlation coefficient (ICC) statistics, and the eGFR agreement between the equations was tested using Bland–Altman plots. The GFR was estimated using the Cockcroft–Gault (CG), Berlin Initiative Study 1 (BIS1), simplified Modification of Diet in Renal Disease (MDRD), MDRD modified for Chinese populations (mMDRD), chronic kidney disease epidemiology collaboration (CKD-EPI), CKD-EPI in Asians (CKD-EPI-Asia), and Ruijin equations.ResultsOverall, the proportion of CKD stages 3–5 (eGFR <60 mL/min/1.73 m2) was calculated as 28.9%, 39.1%, 11.8%, 8.4%, 14.3%, 11.5%, and 12.7% by the eGFRCG, eGFRBIS1, eGFRMDRD, eGFRmMDRD, eGFRCKD-EPI, eGFRCKD-EPI-Asia, and eGFRRuijin equations, respectively. The concordance of albuminuria and decreased eGFR based on the different equations was poor by both the Kappa (<0.2) and ICC (<0.4) statistics. The CKD-EPI-Asia equation resulted in excellent concordance with the CKD-EPI (ICC =0.931), MDRD (ICC =0.963), mMDRD (ICC =0.892), and Ruijin (ICC =0.956) equations for the classification of CKD stages, whereas the BIS1 equation exhibited good concordance with the CG equation (ICC =0.809). In addition, significant differences were observed for CKD stage 1 among all these equations.ConclusionAccurate GFR values are difficult to estimate using creatinine-based equations in older diabetic patients. Kidney function is complex, and the staff need to be aware of the individualized consideration of other risk factors or markers of reduced renal function in clinical practice.

Impact of chronic kidney disease on the outcomes of transcatheter aortic valve implantation: results from the FRANCE 2 registry.

The aim of this study was to assess the influence of chronic kidney disease (CKD) classification on clinical outcomes in patients undergoing transcatheter aortic valve implantation (TAVI). Data of 2,929 consecutive patients undergoing TAVI in the FRANCE 2 registry were analysed. Patients were divided into five groups: CKD 1+2, 3a, 3b, 4, and 5. Both 30-day and one-year mortality rates were significantly increased and positively correlated with CKD severity in all groups. After adjusting for significant influential confounders in a Cox regression multivariate model, CKD 4 and 5 were associated with increased risk of both 30-day mortality and one-year mortality when compared with CKD 1+2 as the reference. This higher mortality was predominantly driven by renal failure and infection in patients with CKD 4 and 5, respectively. Procedural success rate in CKD 5 was significantly lower than that in other groups. All CKD patients trended towards a higher incidence of acute kidney injury (AKI), in parallel with the degree of CKD severity. Classification of CKD stages before TAVI allows risk stratification for 30-day and one-year clinical outcomes. CKD 3b, 4 and 5 correlate with poor outcome and are considered a significant risk for TAVI.

A Comparison of Estimated Glomerular Filtration Rate (eGFR) Based On Serum Creatinine and Cystatin C in Kidney Transplant (KT) Patients.

Background: eGFR based on serum creatinine (SCr) is imprecise but routinely used. Such imprecision can potentially affect chronic kidney disease (CKD) stage classification. Cystatin C is an alternative endogenous marker of GFR. Currently, there is scarce data regarding the usefulness of eGFR based on cystatin C in KT patients. Aim: to compare the Chronic Kidney Disease Epidemiology Colaboration (CKD-EPI) SCr and CKD-EPI cystatin C for estimation of GFR and CKD stage classification in KT patients. Methods: GFR was estimated using SCr and cystatin C based CKD-EPI equations in 58 KT patients beyond 6 months post-KT (ages 19-73, male 67%, cadaveric donor 74%). Patients were classified in CKD stages according to National Kidney Foundation guidelines based on the eGFR obtained from these equations. Data are expressed as:median, range. Results: SCr (mg/dl) and cystatin C were 1.32, 0.55-5.2 and 1.72, 0.79-4.3 respectively. Overall eGFR (ml/min/1.73 m2) was significantly different between SCr and cystatin C based equations (55, 13-122 and 41.5, 12-128 respectively) (p<0.0012). No significant differences were found in CKD stage classification except in stage IV, 6.9% vs 25.9% patients according to SCr and cystatin C CKD-EPI( p<0.005). Correlation between both equations was good (r2=0.88) (fig. 1). The Bland-Altman graph shows most values are within 1.96 SD from the mean (fig.2).Figure: No Caption available.Conclusion: eGFR from SCr based CKD-EPI is different from cystatin C based CKD-EPI in the population studied. Both methods require further efforts to establish their utility as GFR estimates in KT patients.

Improved Glomerular Filtration Rate Estimation by an Artificial Neural Network

BackgroundAccurate evaluation of glomerular filtration rates (GFRs) is of critical importance in clinical practice. A previous study showed that models based on artificial neural networks (ANNs) could achieve a better performance than traditional equations. However, large-sample cross-sectional surveys have not resolved questions about ANN performance.MethodsA total of 1,180 patients that had chronic kidney disease (CKD) were enrolled in the development data set, the internal validation data set and the external validation data set. Additional 222 patients that were admitted to two independent institutions were externally validated. Several ANNs were constructed and finally a Back Propagation network optimized by a genetic algorithm (GABP network) was chosen as a superior model, which included six input variables; i.e., serum creatinine, serum urea nitrogen, age, height, weight and gender, and estimated GFR as the one output variable. Performance was then compared with the Cockcroft-Gault equation, the MDRD equations and the CKD-EPI equation.ResultsIn the external validation data set, Bland-Altman analysis demonstrated that the precision of the six-variable GABP network was the highest among all of the estimation models; i.e., 46.7 ml/min/1.73 m2 vs. a range from 71.3 to 101.7 ml/min/1.73 m2, allowing improvement in accuracy (15% accuracy, 49.0%; 30% accuracy, 75.1%; 50% accuracy, 90.5% [P<0.001 for all]) and CKD stage classification (misclassification rate of CKD stage, 32.4% vs. a range from 47.3% to 53.3% [P<0.001 for all]). Furthermore, in the additional external validation data set, precision and accuracy were improved by the six-variable GABP network.ConclusionsA new ANN model (the six-variable GABP network) for CKD patients was developed that could provide a simple, more accurate and reliable means for the estimation of GFR and stage of CKD than traditional equations. Further validations are needed to assess the ability of the ANN model in diverse populations.

Current equations estimating glomerular filtration rate in primary care: Comparison and determinants

The aims of this study were to compare estimated glomerular filtration rate (eGFR) by Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, to assess the classification of chronic kidney disease (CKD) stages by both equations, and to identify factors associated with differences between both equations in patients with or at high risk of CKD managed in primary care. This was an observational study of 803 patients with CKD, long-standing, severe hypertension and diabetes exclusively managed in primary care. Bias and precision between the two equations used to calculate eGFR were quantified as proposed by Bland and Altman. In 1534 eGFR calculations, mean eGFR(MDRD) was 0.8 ± 3.6 ml/min/1.73 m(2) higher than eGFR(CKD-EPI). Precision between the two equations was ±7.1 ml/min/1.73 m(2). Classification of CKD stages by MDRD or CKD-EPI equations agreed in 93.3% of cases. Age above 70 years, eGFR below 60 and above 120 ml/min/1.73 m(2) were associated with higher eGFR(MDRD) values; and age below 50 years and inadequately controlled hypertension with higher eGFR(CKD-EPI) values. Comparison of eGFR calculated by MDRD and CKD-EPI equations demonstrated no clinically relevant difference. In addition, CKD classification by both equations agreed highly. As both equations performed equally well, the simpler and more established MDRD equation should be preferred in patients with or at high risk of CKD managed in primary care. Patients' characteristics seem to account for previously reported differences in the performance of CKD-EPI and MDRD equations.

Factors Affecting Kidney Function and Stone Recurrence Rate After Percutaneous Nephrolithotomy for Staghorn Calculi: Outcomes of a Long-Term Followup

There are few studies of the long-term outcome of percutaneous nephrolithotomy for staghorn calculi. We report the long-term outcome of percutaneous nephrolithotomy in patients with staghorn calculi. A total of 265 study patients (272 renal units) were followed in the long term for greater than 12 months. The estimated glomerular filtration rate was calculated using the 4-variable modification of diet in renal disease equation. Cases were staged for chronic kidney disease by National Kidney Foundation guidelines. The impact of patient and procedure related factors on renal function as well as stone recurrence was analyzed retrospectively. At a mean ± SD followup of 37.3 ± 25.4 months the chronic kidney disease stage classification was maintained in 177 patients (66.8%) while the classification of 34 (12.8%) and 54 (20.4%) had improved and deteriorated, respectively. Multivariate analysis revealed that an immediate postoperative change in the estimated glomerular filtration rate was the only factor predicting a change in renal function in the long term. Stones recurred in 73 of the 234 kidneys (31.2%) that were stone free 3 months after percutaneous nephrolithotomy. Stone size increased in 24 of the 38 kidneys (63.2%) with residual stones after intervention. Recurrent urinary infections during followup and diabetes were associated with stone recurrence and residual stone enlargement. In almost 80% of patients with staghorn stones renal function was improved or maintained after percutaneous nephrolithotomy, as documented during long-term followup. Stones recurred in a third of the patients with staghorn calculi.