Assessment of the reductions in night-time blood pressure and dipping induced by antihypertensive medication using a home blood pressure monitor

BACKGROUND: Night-time blood pressure (BP) is strongly associated with hypertensive target organ damage; however, no previous studies have compared home BP monitor measurements of the reduction in night-time BP induced by antihypertensive medications with those obtained with ambulatory BP monitors. METHODS: As part of the Japan Morning Surge-Target Organ Protection study, in which candesartan (thiazide diuretics were added, if needed) was administered to hypertensive patients in the morning or at bedtime, 50 hypertensive patients had their night-time home and ambulatory BP successfully measured at the baseline and 6 months. In addition, three night-time home BP readings were taken during sleeping hours (at 2, 3, and 4 o'clock) for 6 months. RESULTS: The mean reduction in night-time BP did not differ significantly between home and ambulatory BP monitoring (10.4±17.9/6.0±12.0 vs. 13.3±14.6/7.6±8.9mmHg, P=0.219/0.344), but the differences varied among individual patients. The reduction in night-time BP according to home BP monitoring was significantly correlated with the value obtained with ambulatory BP monitoring (r=0.51/0.38, P<0.001/=0.006). The reduction in night-time SBP according to home BP monitoring was significantly correlated with the reductions in left ventricular mass index (r=0.385, P=0.013, N=41) and Sokolow-Lyon voltage (r=0.335, P=0.035, N=40). CONCLUSION: Home BP monitoring produces estimates of mean night-time BP reductions comparable to those from ambulatory monitoring, while the differences varied among individual patients. The reduction in night-time home BP according to home BP monitoring is significantly correlated with the reduction in left ventricular hypertrophy.