The home blood pressure monitoring (
HBPM) method that measures blood pressure during sleep hours was reported to be comparable to ambulatory blood pressure monitoring (ABPM) in measuring nighttime blood pressure and detecting nocturnal
hypertension. The aim of this study was to directly compare the prognostic power of nocturnal
hypertension detected by
HBPM versus ABPM for predicting future cardiovascular events. We analyzed nighttime blood pressure (measured by
HBPM and ABPM) data of 1005 participants who were included in the J-HOP study (Japan Morning Surge-Home Blood Pressure). During a follow-up period of 7.6±3.4 years, 80
cardiovascular disease events occurred. The majority (91.8%) of our study population were hypertensive, and 80.7% of participants were using
antihypertensive medication. Nighttime home systolic blood pressure (SBP) was higher compared to nighttime ambulatory SBP (123.0±14.6 versus 120.3±14.4 mm Hg, P<0.001). Nocturnal
hypertension was defined as nighttime home or ambulatory SBP of ≥120 mm Hg. The number of participants with nocturnal
hypertension defined by
HBPM and ABPM was 564 (56.1%) and 469 (46.7%), respectively. Nocturnal
hypertension defined by
HBPM was associated with increased risk of future cardiovascular events: total cardiovascular events (
coronary artery disease and
stroke events; 1.78 [1.00-3.15]) and
stroke (2.65 [1.14-6.20]), independent of office SBP. These results were absent with nocturnal
hypertension defined by ABPM. This is the first comparison prospective study illustrating that uncontrolled nocturnal
hypertension defined by
HBPM (independent of office SBP) is a predictor of future cardiovascular events.