NIGHT-TIME BLOOD PRESSURE IN DIABETES TYPE-1 ASSESSED BY HOME VS. AMBULATORY MONITORING: A PILOT STUDY

Abstract

Objective: To compare night-time (asleep) blood pressure (BP) evaluated by home monitoring (HBPM) vs. ambulatory monitoring (ABPM) in adolescents and young adults with diabetes type-1 (DM1) and examine their association with indices of preclinical target organ damage (TOD). Design and method: Individuals aged 12–30 years with DM1 were subjected to 24-hour ABPM (every 20 min, Microlife WatchBP O3) and 7-day HBPM (daytime: duplicate morning and evening measurements; night-time: 3 measurements per night for 3 nights; Microlife WatchBP Home-N), as well as TOD assessment (left ventricular mass index, carotid intima media thickness, urine albumin excretion). Results: Data from 24 individuals were analysed (mean age 19.8 ± 5.3 [SD] years, men 62.5%, BMI 25.6 ± 4.1 kg/m2, 13% with elevated 24-hour ABPM]. The number of valid ABPM readings was 45.7 ± 1.4/22.4 ± 4.8 (awake/asleep, mean ± SD) and HBPM 26.3 ± 2.1/8.3 ± 2.0 respectively (p < 0.001/ < 0.001). Daytime HBPM was lower than ABPM (by 2.7 ± 0.1/1.9 ± 0.7 mmHg, systolic/diastolic, p < 0.05/ < 0.05), but night-time was higher (difference 5.0 ± 0.6/3.2 ± 0 mmHg, p < 0.01/ < 0.05). There was a strong association between HBPM and ABPM (daytime r = 0.85/0.88, night-time r = 0.68/0.49, systolic/diastolic). There was fair agreement (88%; kappa = 0.33) between ABPM and HBPM in diagnosing nocturnal hypertension (age > = 16 years > = 120/70 mmHg; < 16 years > = 95th centile;) and poor agreement in detecting non-dippers (38%, kappa = 0.032). No significant association of night-time ABPM or HBPM and indices of TOD was found, probably due to small sample size and low prevalence of TOD. Conclusions: These preliminary data in young individuals with DM1 show that nocturnal HBPM is feasible and provides values similar to ABPM. Further research is needed to extend these finding and investigate their clinical relevance in DM1.