The Odyssey of Masked Hypertension in the HOMERUS Trial.

S ome untreated subjects show normal clinic but high home or ambulatory blood pressure (BP). This phenomenon has been called masked hypertension (MH) and may be determined by various factors. The same experience may be observed in treated hypertensive patients and has been labeled with the same term. The prevalence of MH in treated hypertension is variable, from 7% to 20%, depending on different populations studied and frequency of underlying mechanisms, such as smoking habit, coffee use, alcohol abuse, physical activity, and daily and work stress. Some studies have also evaluated the prognostic impact of MH in treated hypertension. These studies included 1559 subjects with normal clinic and home or ambulatory BP who experienced 77 cardiovascular events and 733 patients with MH who experienced 80 events. The adjusted relative risk of cardiovascular events in patients with MH, when compared to those with normal clinic and out of office BP, ranged from 1.62 to 2.8. Thus, these studies suggest that MH has a remarkable clinical relevance. In the present issue of the American Journal of Hypertension, the phenomenon of MH has been further analyzed. Verberk et al investigated the prevalence and persistence of MH in treated hypertension. One hundred sixty-one subjects included in the home BP group of the Home versus Office blood pressure MEasurements: Reduction of Unnecessary treatment Study (HOMERUS) trial (designed for other purposes than those exposed in the report) had clinic BP measurement at eight visits and home BP recording before each visit for 1 year. The MH was defined as clinic BP 140/90 mm Hg and home BP 135/85 mm Hg. During the study, 50% of the patients had MH at least once, whereas 19% had MH at two consecutive visits, 8% at three consecutive visits, and 2% at four consecutive visits. The investigators concluded that MH is common in treated patients, but it is not a persistent phenomenon, probably because of an accidentally low clinic BP at one particular occasion.