PP.05.07

Abstract

Objective: Recent guidelines suggest relying on the ambulatory blood pressure (BP) monitoring (ABPM) derived awake mean to corroborate the diagnosis of hypertension suspected by elevated clinic BP measurement. However, several prospective ABPM studies have found elevated sleep-time BP is a better predictor of cardiovascular disease (CVD) risk than awake BP mean, also in diabetes. We evaluated the combined contribution to CVD risk of clinic, awake, and asleep BP among patients with diabetes participants in the Hygia Project, designed to evaluate prospectively CVD risk by ABPM in primary care centers of Northwest Spain. Design and method: This study involved 2632 patients with type 2 diabetes, 1589 men/1043 women, 65.1 ± 11.6 years of age, with baseline BP ranging from normotension to sustained hypertension according to ABPM criteria, prospectively evaluated throughout a 4.1-year median follow-up. BP was measured at 20-min intervals from 07:00 to 23:00 h and at 30-min intervals at night for 48 h. During monitoring, subjects maintained a diary listing the times of going to bed at night and awakening in the morning. Results: The hazard ratios (HR) of total CVD events for each 1-SD elevation in clinic, awake, and asleep systolic BP (SBP) analyzed separately (adjusted for the significant influential characteristics of age, sex, chronic kidney disease, cigarette smoking, waist perimeter, and history of previous CVD event) were 1.25 [95%CI: 1.17–1.35]; 1.39 [1.30–1.50], and 1.51 [1.41–1.62], respectively (always P < 0.001). Exploration of the combined contribution of all three BP measurements revealed elevation in asleep SBP (HR = 1.55 [1.38–1.75], P < 0.001) but not in clinic BP (1.08 [0.99–1.18], P = 0.082) or awake BP (0.93 [0.82–1.06], P = 0.270) was the only independent BP parameter significantly associated with increased CVD risk. Conclusions: In patients with diabetes, sleep-time SBP mean, but not daytime clinic BP measurement or ABPM-derived awake BP mean, is the only significant and independent prognostic marker of CVD morbidity and mortality. These findings indicate ABPM, but not conventional clinic BP so far mistakenly used to diagnose hypertension and establish therapeutic targets, is a clinical necessity to accurately detect abnormal sleep-time BP and assess CVD risk in diabetes.