Prognostic value of chronic kidney disease in patients with coronary heart disease: Role of estimating equations

Objective: Chronic kidney disease (CKD) increases risk of coronary heart disease (CHD), but the impact of using different equations for estimating kidney function on CHD is not clear yet. This study described the prognostic value of CKD as defined by various creatinine-(Cr-eGFR) and cystatin C-based estimating (Cys-eGFR) equations and their combinations on subsequent cardiovascular disease (CVD) events in patients with CHD. Design: Cohort study. Setting: Patients with coronary heart disease in in-patient rehabilitation and long-term follow-up (mean 63.4 months). Subjects: 1050 patients with coronary heart disease aged 30-70 years at baseline. Methods: CKD was defined as eGFR < 60 mL/min/1.73m(2) (CKD stages 3-5) estimated by three Cr-eGFR equations (Cockroft-Gault equation adjusted for body surface area (CG/BSA), Modi. cation of Diet in Renal Disease Study (MDRD) equation, CKD-EPIcrea) and by two Cys-eGFR equations (Arnal-Dade equation, CKD-EPIcys) and a combination. The primary endpoint of our study was subsequent CVD events. Results: During follow-up 118 patients (11.2%) experienced the outcome of our study. CKD assessed by the CG/BSA, MDRD, and CKD-EPIcrea equations showed no statistically significant association with subsequent CVD events after adjustment for multiple covariates (hazard ratio (HR) 1.45 [95% CI, 0.81-2.59], HR 1.47 [95% CI, 0.84-2.60], and HR 1.31 [95% CI, 0.72-2.83], respectively). By contrast, the Cys-eGFR equations were much stronger associated with subsequent CVD endpoints (Arnal-Dade: HR, 2.01 [95% CI, 1.34-3.04]; CKD-EPIcys HR, 2.22 [95% CI, 1.46-3.37]). The CKD-EPIcys also provided the highest area under the curve value. Conclusion: Our study shows that prevalent CKD is an independent risk factor for subsequent CVD in patients with prevalent CHD and implies that Cys-eGFR equations show a better clinical utility compared to the Cr-eGFR equations. (C) 2010 Elsevier Ireland Ltd. All rights reserved.