Proteinuria in midlife and 39-year total mortality: the Honolulu Heart Program.

BACKGROUND

Previous population-based studies have shown that proteinuria is an independent predictor of total mortality. However, no studies have examined multiple proteinuria measurements or had a follow-up period longer than two decades.

METHODS

Proteinuria was measured by urine dipstick on 6,815 Japanese-American men on two occasions, 6 years apart. Participants were classified into the "no proteinuria" group if both examinations were negative, "transient proteinuria" if either was positive, and "persistent proteinuria" if both were positive and followed for total mortality over 39 years.

RESULTS

Prevalence of transient and persistent proteinuria was 6.4% and 1.3%, respectively. Age-adjusted total mortality rates were 41.9, 55.0, and 71.9 per 1000 person-years follow-up for no, transient, and persistent proteinuria groups, respectively (p for trend <.0001). Multivariate Cox proportional hazards models showed increased total mortality risk in a dose-response manner: HR, 1.40; P < .001 and HR, 2.26; P < .001 for transient and persistent proteinuria groups, respectively (using no proteinuria as reference). Stratified analyses showed stronger associations between proteinuria and mortality among those with prevalent cardiovascular diseases compared with those without.

CONCLUSIONS

Proteinuria was independently associated with higher total mortality risk over 39 years. This risk was stronger among high-risk populations but also remained significant in low-risk populations. Simple urine dipstick can be a good risk assessment tool in the general population.