Race Coefficient Research Articles

Prognostic impact of switching to the 2021 chronic kidney disease epidemiology collaboration creatinine-based equation in Caucasian patients with type 2 diabetes: the Renal Insufficiency and Cardiovascular events (RIACE) Italian Multicenter Study

BackgroundA Chronic Kidney Disease (CKD) Epidemiology Collaboration (EPI) formula not including a Black race coefficient has been recently developed and is now recommended in the US. The new (2021) equation was shown to yield higher estimated glomerular filtration rate (eGFR) values than the old (2009) one in a non-Black general population sample, thus reclassifying a significant number of individuals to a better eGFR category. However, reclassified individuals were previously shown to have a lower risk of progression to end-stage kidney disease, but higher adjusted risks for all-cause death and morbidity and mortality from cardiovascular disease than those not reclassified. This study evaluated the prognostic impact of switching from the 2009 to the 2021 CKD-EPI equation in non-Black individuals with type 2 diabetes.MethodsThe Renal Insufficiency And Cardiovascular Events (RIACE) was a prospective cohort study enrolling 15,773 Caucasian patients in 19 Italian centers in 2006–2008. Cardiometabolic risk profile, treatments, complications, and comorbidities were assessed at baseline and eGFR was calculated with the two equations. Vital status was retrieved on 31 October 2015 for 15,656 participants (99.3%).ResultsWith the 2021 equation, the eGFR value increased in all patients, except for 293 individuals with a 2009 eGFR ≥ 105 ml·min− 1·1.73 m− 2. The median difference was 4.10 ml·min− 1·1.73 m− 2 and was higher in males, older individuals and those in the G2 category. Reclassification decreased the percentage of patients with reduced eGFR from 17.28 to 13.96% and with any CKD from 36.23 to 34.03%. Reclassified individuals had better cardiometabolic risk profile and lower prevalence of complications and use of medications than non-reclassified individuals. Risk of death versus the 2009 G1 category was lower for reclassified than non-reclassified participants in all eGFR categories and, particularly, in each 2009 eGFR category, though difference was significant only in the G4-G5 category. The Receiver Operator Characteristic curves were statistically, but not clinically different with the two equations.ConclusionChanging from the 2009 to the 2021 CKD-EPI equation results in higher eGFR and lower CKD prevalence, with a lower risk of death in reclassified patients with an eGFR < 30 ml·min− 1·1.73 m− 2, but virtually no impact on mortality prediction.Trial registration: ClinicalTrials.gov, NCT00715481, retrospectively registered 15 July, 2008.

Estimated GFR in the Korean and US Asian Populations Using the 2021 Creatinine-Based GFR Estimating Equation Without Race

Rationale & ObjectiveIn 2021, the new Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) updated the creatinine-based estimated glomerular filtration rate (eGFR) equation and removed the coefficient for race. The development and validation of this equation involved binarizing race into Black and non-Black, involving few Asian participants. This study aimed to examine the difference between the 2021 equation and the previous 2009 equation on CKD prevalence estimates in two Asian populations. Study DesignObservational study utilizing two national surveys. Setting & ParticipantsParticipants from the 2019 Korea National Health and Nutrition Survey and participants self-reported as Asian from the 2011-2020 United States (US) National Health and Nutrition Survey. ExposureeGFR using 2009 and 2021 CKD-EPI creatinine equation. OutcomesPrevalence of CKD (eGFR <60 mL/min/1.73 m2 or urine albumin-to-creatinine ratio [UACR] ≥30 mg/g) Analytical ApproachSampling-weighted prevalence estimated by the 2009 and 2021 equations as well as the percentage individuals with CKD G3+ by the 2009 equation being reclassified as not having CKD G3+ by the 2021 equation. ResultsThe prevalence of CKD estimated by the 2021 equation was 9.75% (95% confidence interval [CI] 8.80–10.80%) in Koreans and 11.60% (95% CI 10.23–13.13%) in US Asians. The prevalence of CKD estimated by the 2021 equation was slightly lower compared that by the 2009 equation in both Korean and US Asian populations, by 0.63% (95% CI 0.44–0.90%) and 0.84% (95% CI 0.52–1.34%), respectively. Further, 32.8% and 30.2% of Koreans and US Asians with CKD G3-5, respectively, by the 2009 equation were reclassified as not having CKD G3-5 when the eGFR was calculated by the 2021 equation. LimitationsMeasured GFR was not available. ConclusionsThe 2021 CKD-EPI creatinine equation led to a small decrease in CKD prevalence in both Korean and US Asian populations, and of similar magnitude, resulting in significant reclassification among those originally classified as having CKD G3+.

#840 Kidney cancer, treatment with nephrectomy and survival in chronic kidney disease (CKD)

Abstract Background and Aims People with chronic kidney disease (CKD) have increased incidence of kidney cancer and poorer survival post-diagnosis compared to people without CKD. Nephrectomy, either partial or radical is the primary treatment for many kidney cancers and can be curative even in cases with locally advanced disease or single metastasis. We hypothesised that nephrectomy may be less frequently undertaken in people with kidney cancer and pre-existing CKD and that this might contribute to poorer survival in this group. Method Using data from the prospective research cohort UK Biobank (n = 502,536) linked to cancer registry, participants with available biochemistry and a new diagnosis of kidney cancer during follow-up were identified. Occurrence of nephrectomy was extracted from linked hospital data and all-cause mortality data from death certification records. Estimated glomerular filtration rate (eGFRCr) was calculated by CKD-EPI 2009 formula with race coefficient, as this was the formula recommended for use in the UK at the time of recruitment to UK Biobank. Cox proportional hazards models tested associations between eGFRCr and i) undergoing nephrectomy and ii) all-cause mortality by 10 ml/min/1.73 m2 decline from a reference value of 90 ml/min/1.73 m2. We additionally conducted subgroup analyses for nephrectomy and all-cause mortality within eGFRCr categories &amp;gt;105, 90-105, 75-90 (reference), 60-75, 45-60, 30-45 and &amp;lt;30 ml/min/1.73 m2. Both models were adjusted for age, sex, diabetes mellitus, hypertension, stroke, ischaemic heart disease, body mass index and socioeconomic deprivation. The all-cause mortality model was additionally adjusted for undergoing nephrectomy. Results There were 2053 participants with a new diagnosis of kidney cancer and sufficient biochemical data for inclusion. Of these, 935 (46%) had eGFRCr 60-90 ml/min/1.73 m2 and 139 (7%) had eGFRCr &amp;lt;60 ml/min/1.73 m2. Median time from baseline to kidney cancer diagnosis was 5.8 (IQR 0.9, 8.8) years. Median follow-up time after a diagnosis of kidney cancer was 3.4 (IQR 0.9, 6.6) years. For each 10 ml/min/1.73 m2 decline in eGFRCr below 90 ml/min/1.73 m2, there was no significant difference in likelihood of receiving nephrectomy (HR 1.05, p = 0.08) and no significant difference in likelihood of all-cause mortality (HR 1.03, p = 0.23). People with moderate-advanced CKD had increased hazards of all-cause mortality compared to the reference group (eGFRCr 75-90 ml/min/1.73 m2) when models were run by eGFRCr category (eGFRCr 30-45—HR 1.9 95% CI 1.3-3.0; eGFRCr &amp;lt;30—HR 2.0 95% CI 1.0-4.0). Conclusion In UK Biobank participants with kidney cancer and mild CKD, there was no significant difference in likelihood of nephrectomy or in hazards of all-cause mortality associated with declining eGFRCr as a continuous variable. Moderate to advanced CKD (eGFR &amp;lt;45) was associated with increased all-cause mortality despite adjustment for nephrectomy, suggesting that this finding is not explained by reduced access to surgical treatment.

Play it safe: renal function after bilateral flexible ureteroscopy for kidney stones.

We searched for perioperative renal function deterioration risk factors in patients that underwent bilateral flexible ureteroscopy (fURS) for kidney stones. From August 2016 to February 2020, symptomatic patients > 18years old with bilateral kidney stones up to 20mm in each side were prospectively studied. Serum creatinine samples were collected on admission to surgery, immediate postoperative (IPO), on POD 3, 10, and 30. Estimated glomerular filtration rate (eGFR) was calculated using Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI) without a race coefficient. Thirty patients underwent bilateral fURS. Comparing to preoperative eGFR, median IPO and POD3 eGFR (p < 0.001) were significantly lower, and POD10 (p = 0.092) and POD30 (p = 0.648) were similar to preoperative eGFR. During follow-up, 22/30 (73.3%), 14/30 (46.7%), and 7/30 (23.3%) of the patients presented a decrease > 10% eGFR, > 20% eGFR, and > 30% eGFR, respectively. Multivariate analysis demonstrated that lower preoperative eGFR is a risk factor for eGFR < 60mL/min/1.73m2, p = 0.019 [1.021-1.263; 1.136]; ASA > 1 is a risk factor for decrease of eGFR > 10%, p = 0.028 [1.25-51.13; 8.00]; longer operative time is a risk factor for decrease of eGFR > 20%, p = 0.042 [1.00-1.05; 1.028]; and operative time ≥ 120min is a risk factor for decrease of eGFR > 30%, p = 0.026 [0.016-0.773; 0.113]. Renal function suffers a reversible decrease after bilateral fURS. Our study suggests that adequate selection of patients and maintaining operative time < 120min are relevant factors in preventing acute renal function deterioration following bilateral fURS.

Consistent Race Performance in Racing Pigeons: A Case Report Confirming a Favorable Genetic Profile

A recent multivariate analysis showed that racing pigeons had a better race performance based on DRD4 and F-KER genotypes that were independently statistically significant and those racing pigeons with both DRD4 CCCT and F-KER TT had the lowest race coefficient, i.e. the best race performance. This result indicated that 50% birds with this genotype were consistently in the top 10% in the race results. To date, this is the first multigene genotype reported relating to race performance. In 2023, a consistently performing racing pigeon scored in or around the top 10% in all races of a 5 race series ranging from 100 mile to 350 miles. Retrospectively, this bird was shown to have indeed DRD4 CCCT and F-KER TT. Another bird while distantly family related, showed top performance only in the final long distance race but lacked consistency throughout the race series; this bird not have the consistency genotype profile. We pose the hypothesis that birds with both DRD4 CCCT and F-KER TT are more likely to score consistently in the Top 10% in a race series than birds without. This would need to be confirmed in a larger study in particular including Ace Champion birds with consistent top 10% race performance.

Clinical Impacts of Implementing the 2021 Race-Free Chronic Kidney Disease Epidemiology Collaboration Estimated Glomerular Filtration Rate.

Estimated glomerular filtration rate (eGFR) has become incorporated into multiple clinical management situations. Historically, equations included a Black race coefficient, which lacked biological plausibility and created potential to exacerbate health disparities. A new equation created in 2021 changed the weighting of age, sex, and creatinine by modeling against a diverse cohort and removing the Black race coefficient. A variety of clinical outcomes including kidney disease risk stratification, medication dosing, patient eligibility for clinical trials, and kidney donation are impacted by implementation of the new equation. Nearly 2 years after its initial publication, many studies have reported on observed analytical performance of the 2021 eGFR determined as diagnostic concordance and percentage of estimates within 30% of measured GFR. Additionally, the potential clinical impacts following adoption of the new eGFR among different patient populations has also been reported. Here we review these studies with a focus on assessing the data associated with the transition from 2009 to 2021 Chronic Kidney Disease Epidemiology Collaboration equations. The reported interindividual variation in eGFR performance is significantly larger than any potential benefit derived from race coefficients. Both the 2021 eGFR and the 2009 eGFR analytical performance fall short of the validation cohort performance in most cohorts. However, the 2021 analytical is similar or better than the 2009 eGFR in most cohorts. Implementing the 2021 eGFR will remove a systematic overestimation of kidney function among Black patients.

New race-free creatinine- and cystatin C-based equations for the estimation of glomerular filtration rate and association with cardiovascular mortality in the AtheroGene study

Renal function is associated with cardiovascular outcomes and mortality. Among equations used to eGFR, CKD–EPI equations show more accurate association with cardiovascular risk and mortality than MDRD. Recently, new CKD–EPI equations were proposed which do not include race and would be considered sufficiently accurate to estimate eGFR in clinical practice. It is unknown if these new race-free equations are comparably well associated with cardiovascular outcomes in high-risk individuals. The analysis was performed in the AtheroGene Study cohort including patients at high cardiovascular risk. eGFR was determined using the established as well as the recently developed formulas which are calculated without the otherwise existing coefficient for black race. The outcome was cardiovascular death. Analyses included Cox-proportional hazard regression and area-under-the-curve calculation. The analysis included 2089 patients followed up for a median of 3.8 years with a maximum of 6.9 years, corresponding to an overall period of 7701 patient-years. Cardiovascular death occurred in 93 (4.45%), corresponding to an annualized rate of 1.2/100 person-years. In all Cox regression analyses, the estimated adjusted GFR was an independent predictor of cardiovascular death. The equations which included cystatin C showed higher C-index compared to those which did not include cystatin C (0.75–0.76 vs. 0.71, respectively). The equations for the estimation of eGFR which include cystatin C are better associated with cardiovascular death compared to the race-free equations which include only creatinine. This finding adds on the related literature which supports the elimination of race in GFR-estimating equations, and promotion of the use of cystatin C.

Plasma proenkephalin A and incident chronic kidney disease and albuminuria in the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort

BackgroundPlasma proenkephalin A (PENK-A) is a precursor of active enkephalins. Higher blood concentrations have been associated with estimated glomerular filtration rate (eGFR) decline in European populations. Due to the significant disparity in incident chronic kidney disease (CKD) between White and Black people, we evaluated the association of PENK-A with incident CKD and other kidney outcomes among a biracial cohort in the U.S.MethodsIn a nested cohort of 4,400 participants among the REasons for Geographic And Racial Differences in Stroke, we determined the association between baseline PENK-A concentration and incident CKD using the creatinine-cystatin C CKD-EPI 2021 equation without race coefficient, significant eGFR decline, and incident albuminuria between baseline and a follow-up visit 9.4 years later. We tested for race and sex interactions. We used inverse probability sampling weights to account for the sampling design.ResultsAt baseline, mean (SD) age was 64 (8) years, 49% were women, and 52% were Black participants. 8.5% developed CKD, 21% experienced ≥ 30% decline in eGFR and 18% developed albuminuria. There was no association between PENK-A and incident CKD and no difference by race or sex. However, higher PENK-A was associated with increased odds of progressive eGFR decline (OR: 1.12; 95% CI 1.00, 1.25). Higher PENK-A concentration was strongly associated with incident albuminuria among patients without diabetes mellitus (OR:1.29; 95% CI 1.09, 1.53).ConclusionWhile PENK-A was not associated with incident CKD, its associations with progression of CKD and incident albuminuria, among patients without diabetes, suggest that it might be a useful tool in the evaluation of kidney disease among White and Black patients.

Adding a Coefficient for Race to the 4Kscore Improves Calibration for Black Men.

Black men face a higher incidence of high-risk prostate cancer (PCa) compared with non-Black men. While the 4Kscore is a widely utilized commercial test for PCa risk assessment, it does not currently account for racial differences. The aim of this study is to describe and validate a prespecified race coefficient for the 4Kscore with the goal of improving the accuracy of this test for Black men. Using data from 85 Black men from the initial US prospective validation study, a race coefficient of 0.6 on the log-odds scale was prespecified. We calculated discrimination, calibration, and clinical utility of the 4Kscore with and without this coefficient for Black race in our primary analysis cohort of 205 Black men undergoing biopsy for PCa in a Veterans Affairs (VA) institution. We performed a sensitivity analysis using a combined cohort from the US prospective validation and the VA studies. The mean probability of high-grade PCa from the 4Kscore in the primary cohort increased from 25% to 37% with race coefficient addition. Incorporating the race coefficient improved 4Kscore's calibration in Black men, with consequent improvements in clinical utility based on decision curve analysis. Model discrimination was maintained (AUC 0.825 vs 0.828, P = .14) in the combined cohort of Black and non-Black men from the US prospective and VA studies and the calibration remained largely unchanged. Incorporating a prespecified coefficient for Black race improved calibration and clinical utility of the 4Kscore among Black men and should be added to the 4Kscore.

A Pilot Study for the Kidney Effects of Voxelotor in Sickle Cell Anemia

The kidneys are among the most commonly affected organ systems in sickle cell anemia (SCA) and an estimated 15% of deaths in patients with SCA are attributed to kidney failure (PMID 7993409). Angiotensin converting enzyme-inhibitors and angiotensin receptor blockers have been adopted to treat SCA-related chronic kidney disease (CKD) from the non-SCA literature, although demonstrated efficacy in SCA CKD has been marginal in a limited number of small, short-term studies (PMID 28589652). Therapies that directly target the pathophysiology of SCA-related kidney disease may stabilize or improve kidney function. Both the rate of hemolysis and the degree of anemia are associated with the development and progression of CKD in SCA (PMID 24329963, 21523807). Voxelotor inhibits hemoglobin polymerization in SCA red blood cells in the deoxygenated state, leading to a reduction in the rate of hemolysis and an increase in hemoglobin concentration. We conducted a pilot study to determine whether voxelotor can improve kidney function in adults with SCA (NCT 04335721). SCA (HbSS or HbSβ 0-thalassemia) patients ≥ 18 years old and with urine dipstick-defined hemoglobinuria (+ for blood &amp; ≤ 2 red blood cells/high power field), CKD stage 1 or 2 (urine albumin-to-creatinine ratio [ACR] ≥ 30 mg/g &amp; estimated glomerular filtration rate [eGFR] ≥ 60 mL/min/1.73m 2), and hemoglobin concentrations of 5.5 - 10.5 g/dL were eligible. The eGFR was calculated using the CKD-EPI 2009 creatinine-based equation without the race coefficient and the 2012 cystatin C-based equation. Patients were randomized to voxelotor 1,500mg/day for 48 weeks or standard of care, as defined by their primary SCA provider. First or second void urines were collected for urine ACR measurements. The primary endpoint was the change in urine ACR from the mean values at baseline and screening versus the mean values at 47 and 48 week visits. One patient randomized to standard of care was started on voxelotor at week 24 by his provider to improve his hemoglobin concentration. This patient is included in the voxelotor treatment group in combined analysis; the change in laboratory measures in this patient is based upon changes from the mean of values at week 12 and 24 to week 47 and 48 visits. Median and range values are provided. Between 3/2021 and 6/2022, 8 SCA patients with hemoglobinuria and urine ACR &amp;gt; 30mg/g crt observed during routine clinic visits were screened and 6 met the inclusion criteria. The median age of the enrolled cohort was 36 (27 - 63) years, 4 were male, 4 were on stable doses of hydroxyurea (median dose 1000mg/day; 500 - 1500mg/day) and 2 were on stable doses of lisinopril (5, 20mg/day) for at least 90 days before screening. Two other patients had been on lisinopril in the past but developed hyperkalemia prior to enrollment. The median values of kidney function measures at screening and baseline study visits were as follows: urine ACR, 251 (32 - 3132) and 392 (80 - 3101) mg/g crt; creatinine-based eGFR, 109 (93 - 136) and 115 (88 - 137) mL/min/1.73m 2; and cystatin C-based eGFR, 82 (61 - 141) and 85 (61 - 128) mL/min/1.73m 2, respectively. SCA patients who received voxelotor (n = 4) had a median increase in hemoglobin concentration of +0.9 g/dL (-0.4 - +2.6 g/dL) and reductions in indirect bilirubin concentration of -2.2 mg/dL (0 - -4 mg/dL) and reticulocyte % of -2.7% (-1.2 - -4.9%). Urine ACR (-59%, -21% - -100%) improved in SCA patients treated with voxelotor but worsened in those who received standard of care without voxelotor (n = 2) (+86.3%, 64 - 108%) (P=0.009) (Figure 1A). 24-hour urine protein concentrations also improved in those that received voxelotor (-45%, -25% - -100%) but increased in those who did not receive voxelotor (+122%, 113 - 131%) (P = 0.002) (Figure 1B). Changes in creatinine- and cystatin-C based eGFR from baseline were not significantly different between patients who received voxelotor and those who did not. This pilot study demonstrates that SCA patients with hemoglobinuria and early stages of CKD treated with voxelotor may have significant improvements in urine ACR and proteinuria after 24 - 48 weeks of therapy. These preliminary results support the concept that improving hemolytic anemia could be a targeted therapeutic approach to reduce biomarkers of kidney dysfunction, and they warrant larger, prospective clinical studies.

Promoting Anti-Racism in Clinical Practice: Lessons Learned in the Process of Removing the Race Coefficient from the Estimated Glomerular Filtration Rate Algorithm

Promoting Anti-Racism in Clinical Practice: Lessons Learned in the Process of Removing the Race Coefficient from the Estimated Glomerular Filtration Rate Algorithm

Estimated glomerular filtration rate among intensive care unit survivors: From the removal of race coefficient to cystatin C-based equations

PurposeBlack race coefficient used in serum creatinine (sCr)-based estimated glomerular filtration rate (eGFR) calculation may perpetuate racial disparities. Among intensive care unit (ICU) survivors, sCr overestimates kidney function due to sarcopenia. Cystatin C (cysC) is a race- and muscle mass-independent eGFR marker. We investigated the impact of removing the race coefficient from sCr-based eGFR and compared cysC- and sCr-based eGFR in ICU survivors. Materials and methodsAmong 30,920 patients from 2 institutions in the Bronx and Boston, eGFR was calculated at hospital discharge using sCr-based equations with and without race coefficient (eGFRsCr2009 and eGFRsCr2021). In a subset with available cysC between ICU admission and 1-year follow-up, sCr- and cysC-based estimates were compared. ResultseGFRsCr2021 was higher than eGFRsCr2009 by a median of 4 ml/min/1.73 m2 among non-Black patients and lower by a median of 8 ml/min/1.73 m2 among Black patients. Removing race coefficient reclassified 12.9% of non-Black subjects and 16.1% of Black subjects to better and worse eGFR category, respectively, and differentially impacted the prevalence of kidney dysfunction between the institutions due to differences in racial composition. Among 51 patients with available cysC (108 measurements), cysC-based estimates were lower than sCr-based estimates (median difference 9 to 16 ml/min/1.73 m2), resulting in reclassification to worse eGFR category in 34% to 53.5% of measurements. ConclusionsAmong ICU survivors, removal of race coefficient leads to lower eGFR in Black patients and may contribute to overestimation of kidney function in non-Black patients. While cysC is rarely used, estimates based on this marker are significantly lower than those based on sCr.

Performance of the race-free CKD-EPI creatinine-based eGFR equation in a Danish cohort with measured GFR.

In 2021, an updated Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation for estimated glomerular filtration rate (eGFR) without a coefficient for race (CKD-EPI21) was developed. The performance of this new equation has yet to be examined among specific patient groups. We compared the performances of the new CKD-EPI21 equation and the 2009 equation assuming non-Black race (CKD-EPI09-NB) in patients with GFR measured by chromium-51-EDTA plasma clearance at Aarhus University Hospital in Denmark during 2010-18. We examined bias, accuracy, precision and correct classification of chronic kidney disease (CKD) stage using chromium-51-EDTA clearance as the reference standard. We assessed the performance in the total cohort, cancer patients and potential living kidney donors. We also assessed the performance stratified by CKD stage in the total cohort. In this predominantly white population, the CKD-EPI21 equation performed slightly better than the CKD-EPI09-NB equation in both the total cohort (N=4668), and in cancer patients (N=3313) and potential living kidney donors (N=239). In the total cohort, the CKD-EPI21 equation demonstrated a slightly lower median absolute bias (-0.2 versus -4.4mL/min/1.73 m2), and a similar accuracy, precision and correct classification of CKD stage compared with the CKD-EPI09-NB equation. When stratified by CKD stage, the CKD-EPI09-NB equation performed slightly better than the CKD-EPI21 equation among patients with a measured GFR (mGFR) <60mL/min/1.73 m2. In a selected cohort of Danish patients with mGFR, the CKD-EPI21 equation performed slightly better than the CKD-EPI09-NB equation except for patients with a mGFR <60mL/min/1.73 m2, where CKD-EPI09-NB performed slightly better although the differences were considered clinically insignificant.

B-039 Method Performance Evaluation of the Siemens Atellica Cystatin C Assay on the CH930 Instrument

Abstract Background The National Kidney Foundation and American Society of Nephrology Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease published recommendations on the implementation of the CKD-EPI 2021 equation to calculate eGFRcr without a race coefficient. Clinical practice recommendations also suggest increasing availability of Cystatin C testing which can be a more reliable marker of renal function than creatinine for select adults with eGFRcr near medical decision points and in situations where non-GFR factors may have a large effect on serum creatinine. This study evaluated the method performance characteristics of the Cystatin C assay on the Siemens Atellica CH930 analyzer. The assay measures agglutination of latex particles coated with anti-cystatin C antibody at 571/805 nm and is approved for determination of Cystatin C in serum and plasma (lithium heparin, and EDTA). Methods Cystatin C reagent lot 2114231 and calibrator lot 560956 were used in the study. Intra-run precision was evaluated using BioRad IntelliQ Immunology Control (Level 1 lot 68991, Level 2 lot 68993). Inter-run precision was evaluated over 20 consecutive days. Mean, SD, and CV were calculated and compared to manufacturer precision claims in the IFU and BioRad UNITY™ Interlab Reports. Linearity was evaluated using AUDIT MicroControls Cystatin C Linearity LQ (Lot 06901). Accuracy was evaluated by measuring 40 serum samples on the Atellica CH930 and Roche Diagnostics Tina-Quant Cystatin C Gen 2 assay. Acceptable criteria were defined as a calculated slope between 0.9–1.1 and r greater than 0.995. Appropriateness of the adult reference interval was evaluated with 20 female and 20 male presumably healthy donors. Acceptability was defined as less than 10% of results outside the proposed range. Results Intra-run CV ranged from 2.3–9.2% (Level 1 QC) and 1.2–2.6% (Level 2 QC) across four different CH930 instruments. Level 1 precision did not verify the manufacturer claim of ≤3.6% CV on 3 out of 4 instruments. Level 2 precision did not verify the manufacturer claim of ≤1.7% CV for any instrument tested. Using BioRad UNITY™ peer performance as targets, 3 of 4 instruments had CV ≤6.7% for Level 1 and all instruments had CV ≤2.8% for Level 2. Inter-run precision for Level 1 QC was ≤5.94% CV which was less than the BioRad Peer Group CV. Linearity material spanned 0.490–5.893 mg/L and results were within manufacturer’s expected ranges. Method comparison with the Roche Tina-Quant Gen 2 assay had a calculated slope of 0.954, intercept of 0.094, and r value equal to 0.9993. Thirty-nine of 40 results were within 10% of the reference method (range 0.74–5.45 mg/L). Verification of the reference interval using presumably healthy donors resulted in 5.3% (2/38) of results outside the proposed range. Conclusion With the exception of precision, all other manufacturer-claimed performance specifications for the Siemens Atellica Cystatin C assay were verified using four CH930 instruments at our institution.

#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.

Comparison of CG, CKD-EPI[AS] and CKD-EPI[ASR] equations to estimate glomerular filtration rate and predict mortality in treatment naïve people living with HIV in Zimbabwe

BackgroundRenal impairment in people living with HIV (PWH) in Sub-Saharan Africa is common and associated with increased morbidity and mortality. The ideal equation to estimate glomerular filtration rate (eGFR) in this population remains unclear. That which best predicts clinical risk may be the most appropriate while validation studies are awaited. Here we compare the Cockcroft-Gault (CG), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI[ASR]) and the CKD-EPI equation with the race coefficient removed (CKD-EPI[AS]), in a population of anti-retroviral therapy (ART) naïve PWH in Zimbabwe to assess which equation best predicts mortality.MethodsA retrospective cohort study of treatment naïve PWH at the Newlands Clinic in Harare, Zimbabwe was completed. The study included all patients commencing ART between 2007 and 2019. Predictors of mortality were assessed by multivariable logistic regression.ResultsA total of 2991 patients were followed-up for a median of 4.6 years. The cohort was 62.1% female, with 26.1% of patients having at least one comorbidity. The CG equation identified 21.6% of patients as having renal impairment compared with 17.6% with CKD-EPI[AS] and 9.3% with CKD-EPI[ASR]. There was a mortality rate of 9.1% across the study period. The highest mortality risk was seen in those with renal impairment as determined by the CKD-EPI[ASR] equation for both eGFR < 90 and eGFR < 60 with OR 2.97 (95%CI 1.86–4.76) and OR 10.6 (95%CI 3.15–18.04) respectively.ConclusionIn treatment naïve PWH in Zimbabwe, the CKD-EPI[ASR] equation identifies patients at highest risk of mortality when compared to the CKD-EPI[AS] and CG equations.

MP12-03 IMPLICATIONS OF RACE FREE RENAL FUNCTION EQUATIONS ON BLACK PATIENTS WITH RENAL CELL CARCINOMA

You have accessJournal of UrologyCME1 Apr 2023MP12-03 IMPLICATIONS OF RACE FREE RENAL FUNCTION EQUATIONS ON BLACK PATIENTS WITH RENAL CELL CARCINOMA Benjamin N. Schmeusser, Arnold R. Palacios, Eric Midenberg, Reza Nabavizadeh, Adil Ali, Dattatraya H. Patil, R. Donald Harvey, Janetta Bryksin, Michael J. Connor, Kenneth Ogan, Mehmet A. Bilen, and Viraj A. Master Benjamin N. SchmeusserBenjamin N. Schmeusser More articles by this author , Arnold R. PalaciosArnold R. Palacios More articles by this author , Eric MidenbergEric Midenberg More articles by this author , Reza NabavizadehReza Nabavizadeh More articles by this author , Adil AliAdil Ali More articles by this author , Dattatraya H. PatilDattatraya H. Patil More articles by this author , R. Donald HarveyR. Donald Harvey More articles by this author , Janetta BryksinJanetta Bryksin More articles by this author , Michael J. ConnorMichael J. Connor More articles by this author , Kenneth OganKenneth Ogan More articles by this author , Mehmet A. BilenMehmet A. Bilen More articles by this author , and Viraj A. MasterViraj A. Master More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003227.03AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Race is no longer recommended in estimated glomerular filtration rate (eGFR) equations. The resulting lower eGFR may positively impact black patients, such as with earlier nephrology referral and renal transplant eligibility. The impact of race-free equations on black patients with renal cell carcinoma (RCC)–a cohort more likely to experience inferior cancer outcomes–has not been fully examined. Renal function assessment is important in patients with RCC given the recommendations of nephron sparing approaches (i.e. partial nephrectomy [PN]) over radical (RN) in patients with CKDIIIa or estimated post-nephrectomy eGFR of <45 mL/min/1.73m2. Here, we analyze removal of race from eGFR in black patients with RCC and consider the impact of this change in the context of RCC treatment. METHODS: Self-identified black patients undergoing nephrectomy at an academic referral center from 2009-2021 were identified. Patients with end-stage renal disease were excluded. Using preoperative creatinine, height, and weight, eGFR was calculated with the Chronic Kidney Disease Epidemiology Collaboration creatinine equation with and without race (CKD-EPI-WithRace; CKD-EPI-WithoutRace, respectively), and the Modification of Diet in Renal Disease equation with and without race (MDRD-WithRace; MDRD-WithoutRace, respectively). Distribution of patients and changes within CKD stages with different equations was considered. Subgroup analysis was completed on patients with stage III-IV disease only. RESULTS: 459 self-identified black patients that underwent nephrectomy at our institution were identified, 135 of which had stage III-IV disease. eGFR decreased around 10-13ml/min/1.73m2 with removal of the race coefficient. 13-22%, 6-12%, and 2-3% more black patients would fall under common CKD cutoffs of 60, 45, or 30ml/min/1.73m2, respectively, depending on the equation used (Figure 1). Subanalysis of stage III-IV patients only were similar. CONCLUSIONS: Race free renal function equations may result in significantly more black patients being encouraged to undergo nephron sparing treatments. Source of Funding: We gratefully acknowledge the support of the John Robinson Family Foundation and the Chris Churchill Family Foundation © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e133 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Benjamin N. Schmeusser More articles by this author Arnold R. Palacios More articles by this author Eric Midenberg More articles by this author Reza Nabavizadeh More articles by this author Adil Ali More articles by this author Dattatraya H. Patil More articles by this author R. Donald Harvey More articles by this author Janetta Bryksin More articles by this author Michael J. Connor More articles by this author Kenneth Ogan More articles by this author Mehmet A. Bilen More articles by this author Viraj A. Master More articles by this author Expand All Advertisement PDF downloadLoading ...

Predictive performance of the new race-free Chronic Kidney Disease Epidemiology Collaboration equations for kidney outcome in Korean patients with chronic kidney disease.

The new Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations without a race coefficient have gained recognition across the United States. We aimed to test whether these new equations performed well in Korean patients with chronic kidney disease (CKD). This study included 2,149 patients with CKD G1-G5 without kidney replacement therapy from the Korean Cohort Study for Outcome in Patients with CKD (KNOW-CKD). The estimated glomerular filtration rate (eGFR) was calculated using the new CKD-EPI equations with serum creatinine and cystatin C. The primary outcome was 5-year risk of kidney failure with replacement therapy (KFRT). When we adopted the new creatinine equation [eGFRcr (NEW)], 81 patients (23.1%) with CKD G3a based on the current creatinine equation (eGFRcr) were reclassified as CKD G2. Accordingly, the number of patients with eGFR of &lt;60 mL/min/1.73 m2 decreased from 1,393 (64.8%) to 1,312 (61.1%). The time-dependent area under the receiver operating characteristic curve for 5-year KFRT risk was comparable between the eGFRcr (NEW) (0.941; 95% confidence interval [CI], 0.922-0.960) and eGFRcr (0.941; 95% CI, 0.922-0.961). The eGFRcr (NEW) showed slightly better discrimination and reclassification than the eGFRcr. However, the new creatinine and cystatin C equation [eGFRcr-cys (NEW)] performed similarly to the current creatinine and cystatin C equation. Furthermore, eGFRcr-cys (NEW) did not show better performance for KFRT risk than eGFRcr (NEW). Both the current and the new CKD-EPI equations showed excellent predictive performance for 5-year KFRT risk in Korean patients with CKD. These new equations need to be further tested for other clinical outcomes in Koreans.

Social Determinants of Health and Their Impact on the Black Race Coefficient in Serum Creatinine-Based Estimation of GFR: Secondary Analysis of MDRD and CRIC Studies.

The cause for differences in serum creatinine between Black and non-Black individuals incorporated into prior GFR-estimating equations is not understood. We explored whether social determinants of health can account for this difference. We conducted a secondary analysis of baseline data of the Modification of Diet in Renal Disease and Chronic Renal Insufficiency Cohort studies ( N =1628 and 1423, respectively). Data in both study cohorts were stratified by race (Black versus non-Black). We first evaluated the extent to which the coefficient of Black race in estimating GFR from creatinine is explained by correlations of race with social determinants of health and non-GFR determinants of creatinine. Second, we evaluated whether the difference between race groups in adjusted mean creatinine can be explained by social determinants of health and non-GFR determinants of creatinine. In models regressing measured GFR on creatinine, age, sex, and race, the coefficient for Black race was 21% (95% confidence interval, 0.176 to 0.245) in Modification of Diet in Renal Disease and 13% (95% confidence interval, 0.097 to 0.155) in the Chronic Renal Insufficiency Cohort and was not attenuated by the addition of social determinants of health, alone or in combination. In both studies, the coefficient for Black race was larger at lower versus higher income levels. In models, regressing creatinine on measured GFR, age, and sex, mean creatinine was higher in Black versus non-Black participants in both studies, with no effect of social determinants of health. Adjustment for selected social determinants of health did not influence the relationship between Black race and creatinine-based estimated GFR.

Staging of kidney disease today and tomorrow

Since September 2022, there is a new, German-language glossary for the nomenclature of renal function and renal disease, aligned with international technical terms and KDIGO guidelines for a more precise and uniform description of the facts. Terms such as "renal disease," "renal insufficiency," or "acute renal failure" should be avoided and replaced with "disease" or "functional impairment."The KDIGO guideline recommends in patients with CKD stage G3a, in addition to the determination of serum creatinine, the additional determination of cystatin to confirm the CKD stage. A combination of serum creatinine and cystatin C to estimate GFR without taking into account the so-called race coefficient seems to be more accurate in African Americans than the previous eGFR formulas. However, there is no recommendation on this in international guidelines yet. For Caucasians, the formula does not change.Renal function impairment lasting more than 7 days but less than 3 months is called acute kidney disease (AKD). The AKD stage is the critical time window for therapeutic interventions to reduce the risk of progression in kidney disease.A future, expanded AKI definition incorporating biomarkers will allow patients to be divided into subclasses according to functional and structural limitations, thus mapping the two-dimensionality of AKI. By using artificial intelligence, large amounts of data from clinical parameters, blood and urine samples, histopathological and molecular markers (including proteomics and metabolomics data) can be used integratively for the graduation of CKD and thus contribute significantly to individualized therapy.