Objective: 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.
Methods: 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).
Results: 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.
Conclusion: 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.