Proteinuria as a risk factor for cardiovascular disease and mortality in older people: a prospective study

BACKGROUND: The prognostic significance of proteinuria in older people is not well defined. We examined the associations between proteinuria and incident coronary heart disease, cardiovascular mortality, and all-cause mortality in older people. SUBJECTS AND METHODS: Casual dipstick proteinuria was determined in 1,045 men (mean [± SD] age 68 ± 7 years) and 1,541 women (mean age 69 ± 7 years) attending the 15th biennial examination of the Framingham Heart Study. Participants were divided by grade of proteinuria: none (85.3%), trace (10.2%), and greater-than-trace (4.5%). Cox proportional hazards analyses were used to determine the relations of baseline proteinuria to the specified outcomes, adjusting for other risk factors, including serum creatinine level. RESULTS: During 17 years of follow-up, there were 455 coronary heart disease events, 412 cardiovascular disease deaths, and 1,214 deaths. In men, baseline proteinuria was associated with all-cause mortality (hazards ratio [HR] = 1.3, 95% confidence interval [CI] 1.0 to 1.7 for trace proteinuria; HR = 1.3, 95% CI 1.0 to 1.8 for greater-than-trace proteinuria; P for trend = 0.02). In women, trace proteinuria was associated with cardiovascular disease death (HR = 1.6, 95% CI 1.1 to 2.4), and all-cause mortality (HR = 1.4, 95% CI 1.1 to 1.7). CONCLUSION: Proteinuria is a significant, although relatively weak, risk factor for all-cause mortality in men and women, and for cardiovascular disease mortality in women.