Prevalence of masked uncontrolled and treated white-coat hypertension defined according to the average of morning and evening home blood pressure value: from the Japan Home versus Office Measurement Evaluation Study

Objective To evaluate the prevalence of masked uncontrolled and treated white-coat hypertension defined according to the average of morning and evening home blood pressure values. Methods The study population consisted of 3303 essential hypertensive outpatients receiving anti hypertensive treatment in Japan. Information on the characteristics of the patients was collected by a physician's self-administrated questionnaire. The office blood pressure value was calculated as the average of the four readings in two visits. All patients were asked to measure their blood pressure once every morning and once every evening. In the study, we included patients with at least three measurements in the morning and in the evening, respectively. The average of all home blood pressure values was taken as the home blood pressure value. Results The mean value of home systolic/diastolic blood pressure was 136.8/79.3 mmHg, and the mean value of office systolic/diastolic blood pressure was 142.8/80.6 mmHg. Of the 3303 patients, 758 (23.0%) had controlled hypertension (home < 135/85 mmHg and off ice <140/90 mmHg), 628 (19.0%) had masked uncontrolled hypertension (home : 135/85 mmHg and office <140/90 mmHg), 640 (19.4%) had treated white-coat hypertension (home < 135/85 mmHg and office >= 140/ 90 mmHg), and 1277 (38.7%) had uncontrolled hypertension (home >= 135/85 mmHg and office >= 140/90 mmHg). Conclusions Treated white-coat hypertension and masked uncontrolled hypertension were often observed in clinical settings. Physicians need to understand the prevalence of such patients to prevent inadequate diagnosis and treatment in them. Blood Press Monit 10:311-316 (c) 2005 Lippincott Williams & Wilkins.