Increased Ambulatory Arterial Stiffness Index and Pulse Pressure in Microalbuminuric Patients With Type 1 Diabetes

BACKGROUND Ambulatory arterial stiffness index (AASI) has been proposed as an indirect measure of arterial stiffness. The aims of this study were (i) to analyze AASI and pulse pressure (PP) in micro- and normoalbuminuric type 1 diabetes mellitus (T1DM) patients and healthy controls and (ii) to explore the relation between nocturnal blood pressure (BP) reduction, BP variability, and AASI. METHODS Ambulatory BP monitoring was performed in 34 micro- and 34 normoalbuminuric T1DM patients matched for gender, age, and diabetes duration and in 34 nondiabetic controls matched for gender and age. AASI and PP were calculated based on 24-h, day, and night BP recordings. RESULTS AASI increased from the control group (0.30 +/- 0.14) to the normo- (0.35 +/- 0.15) and microalbuminuric group (0.41 +/- 0.19; P < 0.05). After adjustment for nightly systolic BP reduction and systolic daytime BP variability (s.d.) in multivariate analysis, the association weakened and became nonsignificant (P = 0.078). No significant intergroup differences were found when AASI was calculated separately from day and night BP data. There was no significant difference between day and night AASI. The 24-h PP increased from the control group (48 +/- 7 mm Hg) to the normo- (50 +/- 6 mm Hg) and microalbuminuric group (54 +/- 9 mm Hg; P < 0.01). The association remained in the multivariate analysis. Day and night PPs were higher in microalbuminuric patients compared to healthy controls. CONCLUSIONS AASI and PP are higher in microalbuminuric T1DM patients compared to healthy controls. The nocturnal BP reduction and systolic daytime BP variability are determinants of AASI. We propose these associations to reflect biological characteristics of arterial stiffness.