Nocturnal Blood Pressure Elevation Predicts Progression of Albuminuria in Elderly People With Type 2 Diabetes

Abstract

Ambulatory 24-hour pulse pressure predicts progression of albuminuria in persons with diabetes mellitus. The authors assessed whether nocturnal blood pressure (BP) patterns added predictive information and examined the multivariate-adjusted association of nocturnal BP patterns with progression of urine albumin excretion during follow-up in a multiethnic cohort of older people (n=957) with type 2 diabetes mellitus who were free of macroalbuminuria. Albuminuria was assessed by spot urine measurement of albumin-to-creatinine ratio at baseline and annually for 3 years. Participants were categorized according to their sleep/wake systolic BP ratio as dippers (ratio </=0.9; n=295), nondippers (flat nocturnal pattern, ratio >0.9 to 1; n=475), and nocturnal BP risers (ratio >1; n=187). The proportion exhibiting progression of albuminuria in dippers, nondippers, and risers was 17.6%, 22.9%, and 27.3%, respectively (P for linear trend = .01). A nocturnal BP rise was independently associated with progression of albuminuria (hazard ratio, 1.68; 95% confidence interval [CI], 1.09-2.60; P=.02), whereas office pulse pressure was not. When ambulatory 24-hour pulse pressure was added to the model, the nocturnal BP rise remained an independent predictor of progression of albuminuria (hazard ratio, 1.58; 95% CI, 1.02-2.45; P=.04). Nocturnal nondipping (without BP increase) was not an independent predictor. In conclusion, nocturnal BP rise on ambulatory monitoring is superior to office BP to predict worsening of albuminuria in elderly individuals with type 2 diabetes and adds to the information provided by 24-hour pulse pressure.