Kidney Function and Mortality in Octogenarians: Cardiovascular Health Study All Stars.

Objectives To examine the association between kidney function and all-cause mortality in octogenarians. Design Retrospective analysis of prospectively collected data. Setting Community. Participants Serum creatinine and cystatin C were measured in 1,053 Cardiovascular Health Study ( CHS) All Stars participants. Measurements Estimated glomerular filtration rate (e GFR) was determined using the Chronic Kidney Disease Epidemiology Collaboration creatinine (e GFRCR) and cystatin C one-variable (e GFRCYS) equations. The association between quintiles of kidney function and all-cause mortality was analyzed using unadjusted and adjusted Cox proportional hazards models. Results Mean age of the participants was 85, 64% were female, 66% had hypertension, 14% had diabetes mellitus, and 39% had prevalent cardiovascular disease. There were 154 deaths over a median follow-up of 2.6 years. The association between e GFRCR and all-cause mortality was U-shaped. In comparison with the reference quintile (64-75 mL/min per 1.73 m2), the highest (≥75 mL/min per 1.73 m2) and lowest (≤43 mL/min per 1.73 m2) quintiles of e GFRCR were independently associated with mortality (hazard ratio (HR) = 2.49, 95% confidence interval (CI) = 1.36-4.55; HR = 2.28, 95% CI = 1.26-4.10, respectively). The association between e GFRCYS and all-cause mortality was linear in those with e GFRCYS of less than 60 mL/min per 1.73 m2, and in the multivariate analyses, the lowest quintile of e GFRCYS (<52 mL/min per 1.73 m2) was significantly associated with mortality (HR = 2.04, 95% CI = 1.12-3.71) compared with the highest quintile (>0.88 mL/min per 1.73 m2). Conclusion Moderate reduction in kidney function is a risk factor for all-cause mortality in octogenarians. The association between e GFRCR and all-cause mortality differed from that observed with e GFRCYS; the relationship was U-shaped for e GFRCR, whereas the risk was primarily present in the lowest quintile for e GFRCYS. [ABSTRACT FROM AUTHOR]