Reproducibility of white-coat and masked hypertension in ambulatory BP monitoring.

Background: White-coat hypertension and masked hypertension have clinical and prognostic consequences. However, reproducibility of these phenomena is unknown. We examined the reproducibility of the white-coat and masking effects with real-life ambulatory blood pressure monitoring (ABPM).

Methods: In a retrospective analysis of a prospectively assembled ABPM database there were 196 subjects (age 58+/-16 years, 59% female, 73% treated for hypertension) who underwent repeat ABPM for standard clinical indications. White-coat hypertension (or isolated manual uncontrolled hypertension) was defined as normal (<135/85 mmHg) awake blood pressure (BP) and abnormal (>or=140/90 mmHg) manual BP. Masked hypertension (or isolated ambulatory uncontrolled hypertension) was defined as abnormal awake BP with normal manual BP.

Results: Treated and untreated subjects had similar distribution among hypertension subgroups; 16% white-coat hypertension (in treated subjects, isolated manual uncontrolled hypertension), 13% masked hypertension (in treated subjects, isolated ambulatory uncontrolled hypertension), 59% uncontrolled hypertension, 12% normal blood pressure (or controlled hypertension). In the second session the prevalence of white-coat and masked hypertension increased. Of 31 subjects with white-coat hypertension in the first session 19 (61%) remained ambulatory normotensive in the second session, while 18 of 25 (72%) masked hypertensive subjects remained ambulatory hypertensive. The reproducibility of the systolic manual-awake blood pressure difference was not inferior to that of other ambulatory variables. In untreated subjects the reproducibility of white-coat hypertension, masked hypertension and the white-coat effect was even better.

Conclusions: In a real-life ABPM database, we found white-coat hypertension and the masking phenomenon to be reasonably reproducible, as compared to other BP variables.