Night-time home versus ambulatory blood pressure in determining target organ damage

Abstract

This study aimed to evaluate the association of night-time blood pressure (BP) assessed by home blood pressure (HBP) or ambulatory blood pressure (ABP) monitoring with preclinical target organ damage in untreated hypertension. Untreated hypertensive study participants were evaluated with ABP monitoring (24-h) and HBP monitoring during daytime (6 days, duplicate morning and evening measurements) and night-time (automated asleep measurements, three nights, 3-hourly measurements/night). Target organ damage was assessed by echocardiographic left ventricular mass index (LVMI), common carotid intima-media thickness (cIMT), urine albumin excretion (UAE), and ankle-brachial index (ABI). A total of 131 study participants were analysed [mean age 52.1 ± 11.9 (SD) years, BMI 29.9 ± 5.3 kg/m2, men 58%, cardiovascular disease history 6.1%]. Daytime and night-time HBP were slightly higher than the respective ABP values (mean difference for systolic daytime/night-time 3.5 ± 10.6/2.6 ± 9.8 mmHg, P < 0.01 for both comparisons and diastolic -0.3 ± 6.8/1.2 ± 6.2 mmHg, P = NS/0.02, respectively). There was a strong correlation between daytime ABP and HBP (r = 0.71/0.72, systolic/diastolic), as well as between the respective night-time values (r = 0.80/0.79; all P < 0.01). Night-time ABP and HBP presented strong and comparable correlations with all the indices of preclinical target organ damage. In multivariate analyses, both LVMI (R2 = 0.26) and cIMT (R2 = 0.25) were determined by night-time systolic HBP, age and male sex; UAE (R2 = 0.28) by night-time systolic HBP and male sex; ABI (R2 = 0.20) by male sex and night-time home pulse pressure. In untreated hypertensives, night-time BP assessed by home monitoring appears to be as good as night-time ambulatory monitoring in determining preclinical target organ damage.