Proteinuria as a biomarker: risk of subsequent morbidity and mortality.

A standard laboratory renal assessment, concentration of albumin in urine, has been suggested as a biomarker of renal damage, but little data exist on its ability to predict health outcomes in the general population. This 16-year follow-up study of a general population evaluated the utility of this assessment to predict subsequent serious health consequences. Four percent of men and 2% of women aged 45-74 years exhibited proteinuria in a cross-sectional screening of an ambulatory population, with the percentage increasing with age. The finding of proteinuria was predictive of serious health consequences, with adjusted relative risks for subsequent mortality of 1.71 for men and 1.84 for women and adjusted relative risks for renal disease incidence of 3.46 in men and 1.39 in women. Controlling for those factors which might be associated with proteinuria and even excluding early cases did not alter these findings. These data support that causal proteinuria should be considered as a marker for risk of poor health outcomes.