Predictive value of creatinine-based equations of kidney function in the long-term prognosis in United Arab Emirates patients

Abstract

Objectives: Chronic kidney disease (CKD) is an independent predictor of mortality. Several creatinine-based equations are used to assess the estimated glomerular filtration rate or creatinine clearance and mortality prediction in various ethnic populations. Similarly, renal insufficiency is associated with poor prognosis of UAE nationals with cardiovascular disease (CVD) risk factors. However, the equation that best assesses prognosis among these patients is unknown. This study aimed to compare the prognostic abilities of different creatinine-based kidney function equations for predicting all-cause mortality in UAE nationals with vascular comorbidities. Methods: This retrospective observational study analyzed 1186 patients (54.0% men) with CVD risk factors. Multivariable Cox regression analysis was used to evaluate the associations of categorical renal function stages with all-cause mortality. Measures of performance in each equation assessed with respect to all-cause mortality were evaluated and compared to the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation by calculating the C-index, net reclassification index (NRI), and integrated discrimination index. Results: Over a median follow-up of 8.9 years, the cumulative incidence of all-cause mortality was 9.4% (n = 112). After multivariable adjustment, the discriminative ability for all-cause mortality was significantly higher in the body surface area-adjusted Cockcroft-Gault (BSA-CG) formula than in the CKD-EPI equation (C-indices: 0.869 vs. 0.861, respectively, p = 0.037). NRI was significantly positive and favored the BSA-CG formula (0.54; 95% confidence interval: 0.35–0.64) compared to the CKD-EPI equation. Conclusions: Our findings suggest that the BSA-CG equation may have the potential to slightly improve mortality prediction compared to the CKD-EPI equation in UAE nationals with vascular risk. Further large multicenter studies are warranted to confirm our findings.