The importance of home blood pressure measurement for preventing stroke and cardiovascular disease in hypertensive patients: a sub-analysis of the Japan Hypertension Evaluation with Angiotensin II Antagonist Losartan Therapy (J-HEALTH) study, a prospective nationwide observational study.

White-coat hypertension (HT) and masked HT can be identified by home blood pressure (BP) measurement. The prevalence of these subtypes and the associated risk of cardiovascular disease have not been fully investigated among Japanese hypertensive patients. The risk of cardiovascular events due to HT and its relationship with home BP measurement were examined among Japanese hypertensive patients receiving treatment in the Japan Hypertension Evaluation with Angiotensin II Antagonist Losartan Therapy (J-HEALTH) study, a nationwide prospective observational study. Both home and clinic BP were measured during treatment, and the occurrence of cardiovascular events was monitored in 4,596 Japanese patients (mean age of 60.8 years, 43.2% men, and mean follow-up period of 3.5 years). HT was defined as a systolic BP > or =140 mmHg for clinic BP and > or =135 mmHg for home BP while on treatment. The relative risk of all cardiovascular events and stroke increased along with higher clinic and home BP levels during treatment. The prevalence of white-coat HT, masked HT, well-controlled HT, and poorly controlled HT was 12.6%, 19.5%, 23.8%, and 44.1%, respectively. The relative risk of cardiovascular events was not significantly increased in the poorly controlled HT (relative risk [RR]: 2.05, 95% confidence interval [CI]: 0.77-5.45), white-coat HT (RR: 0.77, 95% CI: 0.15-3.96), and masked HT (RR: 2.00, 95% CI: 0.67-5.98) subgroups compared with the well-controlled-HT subgroup; however, the risk of masked HT was similar to that of poorly controlled HT. Monitoring both clinic and home BP is important to diagnose masked HT and to prevent cardiovascular disease in this subtype of HT. However, further investigation is required to fully characterize the cardiovascular risks associated with masked HT among Japanese patients receiving treatment.