Level of kidney function as a risk factor for cardiovascular outcomes in the elderly

Background. There is a high prevalence of both reduced kidney function as well as cardiovascular disease (CVD) in the elderly. We evaluated whether the level of kidney function is an independent risk factor for CVD outcomes in the Cardiovascular Health Study (CHS), a cohort of subjects whose age at baseline was 65 years old or older. Methods. Cox proportional-hazards regression was used to evaluate the association of predicted glomerular filtration rate (GFR) with CVD after adjustment for the major CVD risk factors. We searched for nonlinear relationships between GFR and CVD, as well as interactions between level of kidney function and major CVD risk factors on CVD. Results. A total of 4893 subjects with predicted GFR of 15 to 130 mL/min/1.73 m(2) were included in the analysis. Fifty-six percent were female and the mean age was 73.4 years. Of the subjects, 549 (11.2%) died and 1229 (25.1%) experienced CVD events in 5.05 years of follow-up. Each 10 mL/min/1.73 m(2) lower GFR was associated with an adjusted hazard ratio for CVD, de novo CVD, recurrent CVD and all-cause mortality of 1.05 (1.02, 1.09), 1.07 (1.01, 1.12), 1.04 (0.99, 1.09), and 1.06 (1.00, 1.12), respectively. There was no significant interaction between level of GFR and other traditional CVD risk factors on CVD outcomes. A linear model best described the relationship between GFR and CVD. Conclusion. The level of GFR is an independent risk factor for CVD, de novo CVD, and all-cause mortality in the elderly.