Incident Left Ventricular Hypertrophy in Masked Hypertension

In the PAMELA study (Pressioni Arteriose Monitorate e Loro Associazioni), clinical variables, an echocardiogram, as well as office and ambulatory blood pressure (ABP) were simultaneously measured at baseline and after a 10-year follow-up. The study design allowed us to assess the value of masked hypertension (MH) as a predictor of new-onset left ventricular hypertrophy (LVH). The present analysis included 803 participants without LVH at baseline (left ventricular mass index <115 g/m(2) in men and <100 g/m(2) in women). Based on office and 24-hour mean ABP values, subjects were divided into 3 groups: normal subjects (normotensive, office blood pressure [BP] <140/90 mm Hg and 24-hour mean ABP <130/80 mm Hg), MH (office BP, normal, and 24-hour mean ABP, elevated), and sustained hypertension (office and 24-hour BP, both elevated). At entry, 57 of 803 subjects fulfilled diagnostic criteria for MH (7.1%); 182 participants developed LVH (22.6%). Compared with subjects with normal in-office and out-of-office BP, the risk of new-onset LVH was greater in MH (odds ratio, 2.22; CI, 1.11-4.46, P=0.0250) after adjustment for potential confounders. This was also the case for the absolute increase of left ventricular mass index. Our study provides a new piece of evidence that MH, identified by office and ABP values, is associated with an increased risk of new-onset LVH. Moreover, our findings convey the notion that office BP may inaccurately estimate the risk of incident LVH in the general population.