Value of ambulatory arterial stiffness index and 24-h pulse pressure to predict progression of albuminuria in elderly people with diabetes mellitus.

BACKGROUND Ambulatory 24-h pulse pressure predicts progression of albuminuria in people with diabetes mellitus. It is not known whether the ambulatory arterial stiffness index (AASI) may add to that prediction. METHODS We compared the multivariate-adjusted association of AASI and 24-h pulse pressure with progression of urine albumin excretion during follow-up in a multiethnic cohort of older people with type-2 diabetes mellitus. The baseline evaluation included office and 24-h ambulatory blood pressure (BP) measurements, and a spot urine measurement of albumin-to-creatinine ratio (ACR). The ACR measurements were repeated annually during 3 years. RESULTS The AASI was >or=0.55 units in 47% of those exhibiting progression of albuminuria, and in 37% of those without progression (P = .004), whereas 24-h pulse pressure was >or=65 mm Hg in 50% and 38% of those with and without progression, respectively (P = .001). In repeated measures mixed linear model (n = 1043), after adjustment for several covariates including office pulse pressure, AASI in the fourth quartile was independently associated with higher follow-up ACR (P = .024). However, that association did not persist after adjusting for 24-h pulse pressure, which was an independent predictor (P < .001). Cox proportional hazards models examined progression of albuminuria in 957 participants without macroalbuminuria at baseline. The hazard ratio (95% CI) for AASI >or=0.55 units was 1.37 (1.02-1.83) after multivariable adjustment, including office pulse pressure. But AASI was not an independent predictor after adjustment for ambulatory pulse pressure, which was again an independent predictor (P = .033). CONCLUSIONS Ambulatory 24-h pulse pressure outperformed AASI in predicting progression of albuminuria in elderly people with type 2 diabetes.