Abstract 022: Cystatin C Strengthens the Association of Kidney Function with Mortality and End-Stage Renal Disease
Background: Adding cystatin C to serum creatinine improves accuracy of estimated glomerular filtration rate (eGFR), but the impact on detection, staging and prognosis of chronic kidney disease (CKD) across diverse populations has not been determined.
Methods: Meta-analyses including 11 general population cohorts (N=90,750 participants) and 5 CKD cohorts (N=2,960) with standardized serum creatinine and cystatin C at baseline. We compared associations of baseline GFR estimated by CKD-EPI equations using creatinine (eGFRcr) vs. cystatin C (eGFRcys) with mortality (13,202 deaths from 15 cohorts) and incident end-stage renal disease (ESRD) (1,654 cases from 7 cohorts) during mean follow-up of 7.7 years and studied prognostic consequences of reclassification.
Results: In the general population cohorts, mean eGFRs were 85 ml/min/1.73m2 for both equations but prevalence of eGFR<60 ml/min/1.73m2 was higher for eGFRcys vs. eGFRcr (13.7% vs. 9.7% [12,403 vs. 8,833 of 90,750]). Across all eGFRcr categories (≥90, 60-89, 45-59, 30-44, 15-29, and <15 ml/min/1.73m2), upward and downward reclassification by eGFRcys was associated with lower and higher risk, respectively; net reclassification improvement for eGFRcys compared with eGFRcr was 0.23 (0.18-0.28) for mortality and 0.10 (0.00-0.21) for ESRD. Among participants with eGFRcr 45-59 ml/min/1.73m2 (N=6,358), ~40% were reclassified to higher eGFRcys categories and had lower risks of mortality (adjusted hazard ratio 0.66; 95% CI 0.57-0.77) and ESRD (0.20; 0.08-0.53) compared to those who were not reclassified. Among participants with eGFRcr 60-89 ml/min/1.73m2 (N=43,630), ~13% were reclassified to lower eGFRcys categories and had higher risk for mortality (1.57; 1.39-1.78) and ESRD (2.66; 1.52-4.67) compared to no reclassification. The results for CKD cohorts were largely similar.
Conclusions: Cystatin C strengthens the association of eGFR with risk across diverse populations providing a potentially useful adjunct to eGFRcr for detection and staging of CKD.
- © 2013 by American Heart Association, Inc.