Cardiovascular and mortality risk prediction and stratification using urinary albumin excretion in older adults ages 68–102: The cardiovascular Health Study

Background Elevated urinary albumin excretion (UAE) is associated with the risk of cardiovascular disease (CVD) and all-cause mortality. We tested the hypothesis that elevated UAE improves cardiovascular risk stratification in an elderly cohort aged 68–102 years. Methods We evaluated UAE in 3112 participants of the Cardiovascular Health Study who attended the 1996–1997 examination and had median follow up of 5.4 years. Elevated UAE was defined as urinary albumin to creatinine ratio ≥30 μg/mg. Microalbuminuria and macroalbuminuria were defined as urinary albumin to creatinine ratio 30–300 μg/mg and >300 μg/mg, respectively. Outcomes included CVD (myocardial infarction, stroke, cardiovascular death) and all-cause mortality. Cox proportional hazards models were used to assess the risk of outcomes associated with elevated UAE. Results The prevalence of elevated UAE was 14.3%, 17.1% and 26.9% in those aged 68–74, 75–84 and 85–102 years, respectively. CVD incidence and all-cause mortality were doubled (7.2% and 8.1% per year) in those with microalbuminuria and tripled (11.1% and 12.3% per year) in those with macroalbuminuria compared to those with normal UAE (3.3% and 3.8% per year). The increased CVD and mortality risks were observed in all age groups after adjustment for conventional risk factors. The adjusted population attributable risk percent of CVD and all-cause mortality for elevated UAE was 11% and 12%, respectively. When participants were cross-classified by UAE and Framingham Risk Score categories, the 5-year cumulative incidence of coronary heart disease among participants with elevated UAE and a 5-year predicted risk of 5–10% was 20%, substantially higher than 6.3% in those with UAE <30 μg/mg. Conclusion Elevated UAE was associated with an increased risk of CVD and all-cause mortality in all age groups from 68 to 102 years. Combining elevated UAE with the Framingham risk scores may improve risk stratification for CVD in the elderly.