Creatinine-based Equations Research Articles

Cystatin C-estimated GFR correlates with endothelial function improvements following bariatric surgery.

Obesity is a critical risk factor for chronic kidney disease and cardiovascular disease. The study aimed to explore the relationship between endothelial function, assessed by flow-mediated dilation (FMD), and kidney function, estimated using cystatin C-based eGFR (eGFRcys), in individuals with severe obesity undergoing bariatric surgery. Sixty-five individuals with a BMI >35 kg/m2 scheduled for bariatric surgery were assessed before and 1 year post-surgery. Vascular health was evaluated using FMD, pulse wave velocity and renal resistive index, while kidney function was measured using creatinine-based (eGFRcr) and cystatin C-based (eGFRcys) equations. FMD was calculated using both traditional and allometric scaling methods to account for variations in brachial arterial diameter. Bariatric surgery significantly improved BMI, FMD (p < .001) and eGFRcys (p = .042). Before surgery, eGFRcys was positively correlated with FMD (r = .30, p = .011) and inversely correlated with cf-PWV (r = -.26, p = .020), while eGFRcr showed weaker or non-significant associations with vascular variables. eGFRcys increased post-surgery, correlating positively with improvements in FMD (traditional: r = .26, p = .038; allometric: CI [.19, .82], p = .003). Multivariable mixed models confirmed the robust association between eGFRcys and FMD calculated by allometric scaling, independent of BMI or blood pressure changes. In contrast, eGFRcr showed no significant association with FMD changes. Bariatric surgery enhances both renal and vascular health in individuals with severe obesity. Cystatin C-based eGFR correlates more strongly with endothelial function improvements than creatinine-based eGFR. These findings highlight the utility of cystatin C as an integrative marker for assessing renal and vascular risk in populations affected by obesity undergoing metabolic surgery.

GFRs in Chinese CKD: A systematic review.

GFRs in Chinese CKD: A systematic review.

ASSOCIATION BETWEEN MULTIMORBIDITY AND KIDNEY FUNCTION DECLINE IN OLD AGE: A SWEDISH POPULATION-BASED COHORT STUDY

Abstract We aimed to study the associations between multimorbidity (the presence of ≥2 conditions) and multimorbidity patterns, and the risk of kidney function decline in older adults. 3094 individuals from the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K) were followed between 2001 and 2016. Multimorbidity was operationalised as the number of chronic conditions and multimorbidity patterns identified using latent class analysis. Joint models and Cox regression models were used to explore the associations between multimorbidity, and absolute and relative (≥25% decline from baseline) changes, respectively, in the estimated glomerular filtration rate (eGFR) calculated using the creatinine-based Berlin Initiative Study equation. Mean age of the sample was 73.9 and 87% had multimorbidity. There was a dose-response relationship between the number of chronic conditions, and absolute (β [95% CI] = -0.05 [-0.07;-0.03]) and relative (HR [95% CI] = 1.23 [1.17;1.29]) declines in eGFR. Five patterns of multimorbidity were identified. The Unspecific, low burden pattern had the lowest morbidity burden and was used as the reference category. The Unspecific, high burden and Cardiometabolic patterns showed accelerated absolute (β [95% CI] = -0.15 [-0.26;-0.05] and -0.77 [-0.98;-0.55], respectively) and relative (HR [95% CI] = 1.45 [1.09;1.92] and 3.45 [2.27;5.23], respectively) declines. Additionally, the Cognitive and Sensory pattern showed accelerated relative decline (HR [95% CI] = 1.53 [1.02;2.31]). No associations were found for the Psychiatric and Respiratory pattern. Multimorbidity is strongly associated with accelerated kidney function decline in older age. Individuals with cardiometabolic multimorbidity exhibit a particularly increased risk.

Detection of decline in estimated glomerular filtration rate in patients with type 2 diabetes by cystatin C-based equations.

Aging population is a significant issue in Viet Nam and across the globe. Elderly individuals are at higher risk of chronic kidney disease (CKD), especially those with diabetes. Several studies found that the estimated glomerular filtration rate (eGFR) determined using creatinine-based equations was not as accurate as that determined using cystatin C-based equations. Cystatin C-based equations may be beneficial in elderly patients with an age-associated decline in kidney function. Early determination of eGFR decline and associated factors would aid in appropriate interventions to improve kidney function in elderly patients with diabetes. To determine the utility of cystatin C-based equations in early detection of eGFR decline and to explore factors associated with eGFR decline in elderly patients with diabetes. This cross-sectional study included 93 participants aged ≥ 60 years evaluated in Can Tho University of Medicine and Pharmacy Hospital between October 2022 and July 2023, including 47 and 46 participants with and without diabetes respectively, according to the American Diabetes Association criteria for diabetes. The kappa coefficient, Student's t, Mann-Whitney, χ 2, Pearson's correlation, multivariate logistic regression, and multiple linear regression analyses were employed. The eGFRs were lower with the cystatin C-based equations than with the creatinine-based equations. Good agreement was found between the Modification of Diet in Renal Disease (MDRD) and CKD Epidemiology Collaboration (CKD-EPI) 2021 creatinine-cystatin C equations (kappa = 0.66). In the diabetes group, 30% of the participants had low eGFR. Both plasma glucose and glycated hemoglobin were associated with an increased risk of eGFR decline (P < 0.05) and negatively correlated with eGFR (P = 0.001). By multivariate logistic regression, total cholesterol, and exercise were independently associated with low eGFR. By multiple linear regression, higher plasma glucose levels were correlated with lower eGFR (P = 0.026, r = -0.366). Cystatin C-based equations were superior in the early detection of a decline in eGFR, and the MDRD equation may be considered as an alternative to the CKD-EPI 2021 creatinine-cystatin C equation. Exercise, plasma glucose, and total cholesterol were independently associated with eGFR in patients with diabetes.

Associations between multimorbidity and kidney function decline in old age: A population-based cohort study.

Individual chronic conditions have been linked to kidney function decline; however, the role of multimorbidity (the presence of ≥2 conditions) and multimorbidity patterns remains unclear. A total of 3094 individuals from the Swedish National study on Aging and Care in Kungsholmen (SNAC-K) were followed for 15 years. Multimorbidity was operationalized as the number of chronic conditions and multimorbidity patterns identified using latent class analysis (LCA). Joint models and Cox regression models were used to explore the associations between multimorbidity, and subsequent absolute and relative (≥25% decline from baseline) changes, respectively, in the estimated glomerular filtration rate (eGFR) calculated using the creatinine-based Berlin Initiative Study equation. Mean age of the sample was 73.9, and 87% had multimorbidity. There was an independent dose-response relationship between the number of chronic conditions, and absolute (β [95% confidence interval, CI] = -0.05 [-0.07; -0.03]) and relative (hazard ratio, HR [95% CI] = 1.23 [1.17; 1.29]) declines in eGFR. Five patterns of multimorbidity were identified. The Unspecific, low burden pattern had the lowest morbidity burden and was used as the reference category. The Unspecific, high burden, and Cardiometabolic patterns showed accelerated absolute (β [95% CI] = -0.15 [-0.26; -0.05] and -0.77 [-0.98; -0.55], respectively) and relative (HR [95% CI] = 1.45 [1.09; 1.92] and 3.45 [2.27; 5.23], respectively) declines. Additionally, the Cognitive and Sensory pattern showed accelerated relative decline (HR [95% CI] = 1.53 [1.02; 2.31]). No associations were found for the Psychiatric and Respiratory pattern. Multimorbidity is strongly associated with accelerated kidney function decline in older age. Individuals with cardiometabolic multimorbidity exhibit a particularly increased risk. Increased monitoring and timely interventions may preserve kidney function and reduce cardiovascular risks in individuals presenting with conditions that are characteristic of high-risk multimorbidity patterns.

Applicability of creatinine-based glomerular filtration rate assessment equations to patients with neurogenic bladder

PurposeGlomerular filtration rate (GFR) measured by dynamic renal scintigraphy (Gates method) is used in this study as the standard to investigate the applicability of two creatinine (Cr)-based GFR estimation equations in Chinese patients of different genders, age groups, and GFR stages diagnosed with neurogenic bladder (NB).MethodsGFR values were measured using 99mTc-DTPA renal dynamic imaging, the new serum creatinine (Cr)-based chronic kidney disease epidemiology collaborative group (CKD-EPI) equation, and the equation for the estimated GFR of CKD patients in China, which were designated as sGFR, EPI-GFR, and cGFR, respectively. Pearson’s correlation and linear regression were used to compare the differences, absolute differences, precision, and accuracies of the results of the two equations with sGFR to determine the formula offering better performance for the assessment of patients with NB.ResultsMeasurements from a total of 99 patients with NB were used in the final analysis. Both cGFR and EPI-GFR were moderately correlated with sGFR in both men and women. The overall staging accuracies of EPI-GFR and sGFR were significantly higher than that of cGFR. Among the patients staged, only those with GFRs in the range of 60–89 mL/min/1.73 m2 had moderate correlations between cGFR, EPI-GFR, and sGFR, while the remaining patients had low correlations.ConclusionResearchers found that the equation developed for Chinese CKD patients performed well for patients with NB aged 20–25 years, while the race-neutral CKD-EPI equation performed better in NB patients aged 26–35 years.

Comparison of Measured Glomerular Filtration Rate Versus Estimated Glomerular Filtration Rate in Indian Cirrhotic Patients: Report of a Pilot Study

Comparison of Measured Glomerular Filtration Rate Versus Estimated Glomerular Filtration Rate in Indian Cirrhotic Patients: Report of a Pilot Study

Extending the Lund-Malmö creatinine-based GFR equation to cystatin C – validation results from the European Kidney Function Consortium (EKFC) cohort of children and adults

The aim of the present study was to extend the creatinine-based Lund-Malmö GFR equation for use with rescaled cystatin C (r-LMRCys) and validate it against measured GFR (mGFR) in the EKFC cystatin C cohort of children (n = 2,293) and adults (n = 7,727). Rescaling was obtained by dividing each biomarker by a Q-value, representing the population-specific median biomarker level among healthy individuals. Validation included median bias/precision/accuracy (percent estimates within ±30% of mGFR, P30). Performance was compared with the EKFC-equation (EKFCCys), the CAPA cystatin C equation, the corresponding equations based on rescaled creatinine (r-LMRCr and EKFCCr) and the arithmetic mean of r-LMRCr and CAPA (r-LMRCr+CAPA), r-LMRCr and r-LMRCys (r-LMRMean), and EKFCCr and EKFCCys (EKFCMean). The overall P30 of r-LMRCys in adults was 86.2% (95% CI 85.4%-86.9%), which was 6.6 percentage points (pp; 95% CI 5.8–7.4 pp) higher than for CAPA and similar to r-LMRCr (P30 87.4%, 95% CI 86.6%−88.1%). r-LMRCys and EKFCCys exhibited similar performance both overall and across subgroups of age, sex, GFR and BMI and in children. All three arithmetic mean equations had similar P30-accuracy and generally performed better than the corresponding single-marker equations. Our results show that the Lund-Malmö GFR equation can be adapted for use with rescaled cystatin C with performance that is similar to the best-performing equations based on rescaled creatinine. The generality of the applied biomarker rescaling principle implies that the future demand for population- and biomarker-specific GFR estimating equations can be expected to decrease substantially.

Prenatal metal exposures and kidney function in adolescence in Project Viva.

The developing kidney is vulnerable to prenatal environmental factors such as metal exposure, potentially altering the risk of later-life kidney dysfunction. This study examines the relationship between prenatal metal exposures, individually and as mixtures, and adolescent kidney function in Project Viva, a prospective longitudinal birth cohort in Massachusetts, USA. We used data on metals measured in blood during pregnancy including 15 in the first trimester and four in the second trimester. We calculated estimated glomerular filtration rate (eGFR) in adolescents (mean: 17.7 years) using cystatin C- (eGFRcys) and creatinine-based (eGFRcreat) equations for children. We used linear regression for single metal analyses, and Bayesian kernel machine regression and quantile-based g-computation for mixture analyses, adjusting for relevant covariates. To account for multiple comparisons in the single metal analyses, we applied the Holm-Bonferroni procedure to control the false discovery rate. This study included 371 participants with first trimester metals and adolescent eGFR, and 256 with second trimester metals. Each doubling in first trimester cadmium concentration was associated with lower adolescent eGFRcys (β:-1.51; 95% CI:-2.83, -0.18). Each doubling in first trimester chromium (β:-1.45; 95% CI:-2.71, -0.19), nickel (β:-1.91; 95% CI:-3.65, -0.16), and vanadium (β:-1.69; 95% CI:-3.21, -0.17) was associated with lower adolescent eGFRcreat. After adjusting for multiple comparisons, p-values for associations between adolescent eGFR and chromium, nickel, vanadium and cadmium did not meet the criteria for significance. Metal mixture analyses did not identify statistically significant associations with adolescent eGFR. These findings have important implications for future studies investigating the potential mechanisms through which prenatal metal exposures affect long-term kidney health in children.

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.

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

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

Performance of Three Creatinine-Based Equations in Predicting All-Cause Mortality and Cardiovascular Events in a Multiethnic Asian Population: The Singapore Epidemiology of Eye Diseases Study

Performance of Three Creatinine-Based Equations in Predicting All-Cause Mortality and Cardiovascular Events in a Multiethnic Asian Population: The Singapore Epidemiology of Eye Diseases Study

Comparison of Creatinine-Based Glomerular Filtration Rate Equations for Mortality Prediction in Korean Population: A Retrospective Kangbuk Samsung Health Cohort Study

Comparison of Creatinine-Based Glomerular Filtration Rate Equations for Mortality Prediction in Korean Population: A Retrospective Kangbuk Samsung Health Cohort Study

Nuclear Magnetic Resonance-Based Glomerular Filtration Rate Estimation Is More Closely Associated with Serum Vancomycin Target Trough Achievement vs. Serum Creatinine-Based Equations

Nuclear Magnetic Resonance-Based Glomerular Filtration Rate Estimation Is More Closely Associated with Serum Vancomycin Target Trough Achievement vs. Serum Creatinine-Based Equations

Development and Validation of an Accurate Creatinine-Based Equation to Estimate Glomerular Filtration Rate for the Adult Indian Population: Design and Methods.

Existing creatinine-based equations to estimate glomerular filtration rate (GFR), developed primarily in populations of European and African American ancestry, do not accurately reflect the GFR in the Indian population due to differences in body composition, diet, and other factors. This manuscript describes the rationale and methodology for developing a creatinine-based equation for more accurate GFR estimation in Indian subjects. This cross-sectional study will be conducted in India's two geographically and demographically diverse locations: Chandigarh (north) and Puducherry (south). Participants will include a representative sample from the general population and subjects with chronic kidney disease (CKD), with the latter being recruited from outpatient clinics. A total of 1558 subjects will be enrolled in the discovery and cross-validation cohort and 620 subjects in the external validation cohort. The reference standard for measured GFR (mGFR) will be the plasma clearance of iohexol. Stepwise multiple regression on log-transformed data will determine a set of variables that jointly predict mGFR and identify factors influencing mGFR and estimated (eGFR) in the study population. This study will also explore the performance of mGFR by iohexol measurement from dried blood spots against mGFR from plasma clearance of iohexol. Developing a more reliable and accurate creatinine-based GFR estimating equation will improve CKD diagnosis, classification, and management. The findings will have substantial implications for CKD research in India and other regions with similar populations.

Proenkephalin A 119-159 (penKid) and mortality in stable patients at high cardiovascular risk.

Proenkephalin A 119-159 (penKid) is a novel blood biomarker for real-time assessment of kidney function and was found to be independently associated with worsening kidney function and mortality. A novel penKid-based estimated glomerular filtration rate equation (eGFRPENK-Crea), outperforms current creatinine-based eGFR equations in predicting iohexol or iothalamate plasma clearance-based measured GFR. In this study, we aimed to evaluate the predictive value of penKid and eGFRPENK-Crea for all-cause mortality in stable patients at high cardiovascular risk. Circulating penKid levels were assessed in 615 stable patients hospitalized at the Department of Cardiology at University Hospital Aachen, Germany. The endpoint was all-cause mortality; follow up was 3 years. penKid levels were higher in 46 non-survivors [58.8 (IQR 47.5-85.0) pmol/l] compared to 569 survivors [43.8 (IQR 34.0-58.0) pmol/l; P<.0001]. Univariable Cox regression analyses found penKid and eGFRPENK-Crea to be associated with all-cause mortality (C index 0.703, χ 2 33.27, P<.00001; C index 0.716, χ 2 36.51, P<.00001). This association remained significant after adjustment for significant baseline parameters including age, smoking, chronic heart failure, use of diuretics, leucocytes, body mass index, sex, and creatinine (C index 0.799, χ 2 72.06, P<.00001). Importantly, penKid provided significant added value on top of eGFRCKD-EPI 2021 (eGFRCKD-EPI 2021: C index 0.716, χ 2 34.21; eGFRCKD-EPI 2021+penKid: C index 0.727, χ 2: 40.02; Delta χ 2 5.81; all P<.00001) for all-cause mortality prediction in our cohort. penKid levels and eGFRPENK-Crea is associated with all-cause mortality within a 3-year follow-up period and the addition of penKid on top of eGFRCKD-EPI 2021 provided significant added value in mortality prediction.

Estimating glomerular filtration in young people.

Creatinine-based equations are the most used to estimate glomerular filtration rate (eGFR). The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), the re-expressed Lund-Malmö Revised (r-LMR) and the European Kidney Function Consortium (EKFC) equations are the most validated. The EKFC and r-LMR equations have been suggested to have better performances in young adults, but this is debated. We collected data (GFR) measured by clearance of an exogenous marker (reference method), serum creatinine, age and sex from 2366 young adults (aged between 18 and 25 years) both from Europe and the USA. In the European cohorts (n=1892), the bias (in mL/min/1.73 m²) was systematically better for the EKFC and r-LMR equations compared with the CKD-EPI equation [2.28, 95% confidence interval (1.59; 2.91), -2.50 (-3.85; -1.76), 17.41 (16.49; 18.47), respectively]. The percentage of estimated GFR within 30% of measured GFR (P30) was also better for EKFC and r-LMR equations compared with the CKD-EPI equation [84.4% (82.8; 86.0), 87.2% (85.7; 88.7) and 65.4% (63.3; 67.6), respectively]. In the US cohorts (n=474), the bias for the EKFC and r-LMR equations was better than for the CKD-EPI equation in the non-Black population [0.97 (-1.69; 3.06), -2.62 (-5.14; -1.43) and 7.74 (5.97; 9.63), respectively], whereas the bias was similar in Black US individuals. P30 results were not different between the three equations in US cohorts. Analyses in sub-populations confirmed these results, except in individuals with high GFR levels (GFR ≥120mL/min/1.73 m²) for whom the CKD-EPI equation might have a lower bias. We demonstrated that both the EKFC and r-LMR creatinine-based equations have a better performance than the CKD-EPI equation in a young population. The only exception might be in patients with hyperfiltration.

COMPARISON OF ESTIMATED GLOMERULAR FILTRATION RATE USING DIFFERENT FORMULAS IN TURKISH POPULATION

Objective: Creatinine-based equations are generally used in clinical practice to estimate glomerular filtration rates (GFR), but values are not usually consistent. This study aimed to evaluate the difference between estimated GFR values using different equations. Material and Method: Adult Turkish patients with serum creatinine measurements between January to December 2021 and complete demographic data were included. GFR values were calculated using 5 different formulas. GFR calculated with Cockcroft-Gault were normalized to body surface area and added to the comparison. Difference between GFR values and KDIGO stages were evaluated. Albunin/creatinine ratio (ACR) of patients was also assessed. Result and Discussion: A total of 305 patients with average age of 52.92 years were included. Six different GFR calculations were recorded with median values between 51.70 to 71.77 ml/min/1.73m2. Formula of The Modification of Diet in Renal Disease with the race factor for Turkish population resulted in the lowest eGFR values. The ACR values of only 42 patients were available and it was negatively correlated to all GFR values and positively correlated to all KDIGO stages (p&amp;lt;0.05). There were noteworthy variations in GFR values, based on patient demographics and/or equations. The need for novel practical methods for estimating GFR in general and specific patient populations are necessary.

#2295 Can we detect the evolution of GFR with estimated GFR in patients with ADPKD?

Abstract Background and Aims ADPKD affects about 10% of the patients with CKD. In the disease the formation of cysts replace normal renal parenchyma leading to renal function loss. The evolution of the disease is irregular: some patients lose renal function very fast while others remain stable or have a slow loss. This may have consequences in clinical care. In day-to-day practice, GFR is evaluated by means of formulas, which are algorithms that use creatinine and others markers like age and gender to estimate GFR. However, the accuracy and precision of eGFR in reflecting real GFR in ADPKD is not clear, being this the objective of our study. Method To analyse the capacity of eGFR by creatinine-based formulas in predicting mGFR changes over time. We evaluated patients with ADPKD, who underwent mGFR and eGFR by a group 5 equations at baseline, month 6 and then annually. mGFR was evaluated by the clearance of iohexol using dried blood spots (iohexol-DBS) and eGFR with the following creatinine-based equations: Cockcroft-Gault, aMDRD, CKD-EPI, FAS and EKFC. We calculated renal function decline (GFR decline) using repeated measured with mGFR and eGFR. All subjects have at least 3 repeated evaluations of renal function. The agreement between mGFR and eGFR declines was analysed by the concordance correlation coefficient (CCC). Also, we evaluated the capacity of eGFR decline in detecting diverse degree of GFR decline (a) rapid progressors: mGFR of −5 ml/min/y; (b) moderate progressors: −2 to −5 ml/min/y; (c) stable: &amp;gt; −2 ml/min/y. Results We evaluated 111 (43; 37% men); age: 42 y ± 14, with a 5 ± 1 evaluations of GFR over time (mGFR and eGFR). The average GFR decline was: −2,8 ml/min/year (mGFR); −3,1 (Cockcroft-Gault), −2,9 (aMDRD), −3,0 (CKD-EPI), −2,8 (FAS) and −2,6 (EFKC) According with mGFR decline, 21 patients (19%) were rapid progressors; 46 (41%) moderate progressors and 44 (40%) stable. The agreement between eGFR decline and mGFR decline was poor, reflected by a low CCC: 0.37 (Cockcroft-Gault); 0.76 (aMDRD); 0.80 (CKD-EPI), 0.77 (FAS); 0.81 (EFKC). In general, eGFR decline failed to detect progression of renal function over time. On average, 43% of the rapid progressors, 53% of the moderate progressors and 54% of the stable patients were not detected by any formula, respectively. Finally, a total of 12% and 6% of those stable or moderate progressors were falsely classified as rapid progressors. Conclusion eGFR is not able to reflect properly renal function changes over time in patients with ADPKP in about half of the patients. A relevant number of cases are erroneously considered as rapid progressors or even stable patients. This may have clinical consequences. Whenever possible, mGFR could be considered in this population.

#1329 Assessing eGFR performance against measured GFR stratifying for ethnicity and albumin: development of the AIM CKD UK study

Abstract Background and Aims Accurate measurement of kidney function using estimated glomerular filtration rate (eGFR) is essential for appropriate risk stratification of cardiovascular events, kidney failure and prescribing medications. The AIM CKD UK study (IRAS 320215) will assess the accuracy of current and novel creatinine-based eGFR equations compared to exogenous filtration marker derived measured GFR (mGFR) for people of different ethnicities in large national cohort. We performed a preliminary analysis from a single centre in AIM CKD UK to inform future data collection and assessed: Method All adults (≥18-years) who had paired mGFR and eGFR tests within 30 days between 2009-2022 were included. Patients with mGFR ≥150 ml/min/1.73 m2, incomplete datasets and previous amputations were excluded. Age, reported ethnicity, biological sex, referral specialty, height, weight, exogenous filtration marker, creatinine and albumin concentration were recorded. eGFR was calculated from creatinine, age and sex using five equations (Fig. 1). Each eGFR equation was compared to mGFR using median bias, precision, 30% accuracy (P30). Agreement was demonstrated with Bland-Altman plots. Results were stratified for time between eGFR-mGFR (≤7 days vs 8-30 days) and albumin concentration; low (&amp;lt;35 g/L) vs normal / high (≥35 g/L). Assessment of equation performance in different ethnicity was also stratified for the three largest ethnicity groups (White, Black and South Asian ethnicity). Data were analysed using software R V4.2.2. Results There were 2623 patients who met the inclusion criteria. Mean age was 54.8 ± 13.1 years, with 57.8% male (N = 1515). The majority of patients were White ethnicity (58.7%; N = 1539). Median mGFR was 77 mL/min/1.73 m2 (IQR 62–91 mL/min/1.73 m2). Median serum creatinine concentration was 74 umol/L (IQR 61–90 umol/L). The CKD-EPI 2009 equation, compared to mGFR, demonstrated a median bias of +12.8 mL/min/1.73 m2, percentage bias of 16.9% and P30 of 68.6%. The Lund-Malmo revised equation performed best with median bias of 2.1 mL/min/1.73 m2 (percentage bias 2.9%) and a P30 of 82.7%. Agreement, with ethnicity stratification is summarised in Table 1. The majority of patients (N = 2439; 93.0%) had paired mGFR-eGFR tests within 7-days. There was no significant difference between the median bias of each group (P = .749). 2610 (99.5%) patients had concurrent albumin tests performed; 183 (7.0%) of these patients had low albumin concentrations. Median bias was significantly higher in this group compared to normal/high albumin for each equation (e.g. Low vs Normal/high albumin median bias for CKD-EPI equation = 20.3 vs 12.5 mL/min/1.73 m2; P &amp;lt;. 001). Conclusion The LM revised and European Kidney Function Consortium equations perform best in this cohort. Limitations include selection bias and retrospective data. Future data analysis for the AIM CKD study can include paired samples within 30 days as there is no significant difference between 0-7 and 8-30 days. The impact of serum albumin on mGFR-eGFR association in a larger cohort stratified for confounding variables, such as liver disease, malignancy and body mass index is required.