NIGHT-TIME BLOOD PRESSURE ASSESSED BY HOME VS. AMBULATORY MONITORING IN ADULTS WITH TYPE 2 DIABETES: ASSOCIATION WITH PRECLINICAL TARGET ORGAN DAMAGE

Abstract

Objective: To evaluate the relationship of night-time blood pressure (BP) assessed by home (HBP) or ambulatory BP (ABP) monitoring with preclinical target organ damage in adults with type 2 diabetes (DM2). Design and method: Hypertensive adults with DM2 or pre-diabetes on stable treatment were subjected to (i) 24 h ABP monitoring (20 min intervals, Microlife WatchBP O3), (ii) HBP monitoring (7 days with duplicate morning/evening measurements and 3 nights with 3 measurements/night, Microlife WatchBP Home-N), and measurement of (iii) echocardiographic left ventricular mass index (LVMI), (iv) carotid intima-media thickness (cIMT), (v) aortic pulse wave velocity (PWV) and ankle-brachial index (ABI), (Microlife PWV/ABI), (vi) urine albumin-creatinine ratio (ACR) in 2 different morning samples. Results: Seventy individuals were analyzed (mean age 65.2 ± 9.7 years, 47 males, body mass index 31.6 ± 4.8 kg/m2, 59 with DM2 and 11 with pre-DM). Daytime HBP was slightly higher than daytime ABP (mean difference 2.4 ± 9.3/0.5 ± 4.9 mmHg, systolic/diastolic, p < 0.05/NS). Similarly, night-time HBP was slightly higher than night-time ABP (2.1 ± 6.5/0.8 ± 5.0 mmHg, p < 0.05/NS). There was strong correlation between ABP and HBP (daytime r = 0.77/0.77 and night-time 0.88/0.80, systolic/diastolic) (all p < 0.05). Night-time ambulatory/home pulse pressure presented the following correlation coefficients with indices of target organ damage: LVMI r = 0.23/0.15; cIMT 0.28/0.28; ABI -0.21/-0.23; PWV 0.04/0.05; ACR 0.57/0.50 (p = NS for HBP-ABP comparisons). The agreement between night-time HBP and ABP in identifying individuals with nocturnal hypertension was 81% (kappa statistic = 0.63) and in detection of non-dippers 73% (kappa = 0.44). Conclusions: Night-time HBP monitoring in hypertensive adults with DM2 is feasible, strongly associated with night-time ABP and gives similar correlations with preclinical target organ damage. These methods also present substantial agreement in identifying individuals with nocturnal hypertension.