Prognostic Importance of White Coat Hypertension: Two out of Three?.

In a long-term, population-based study, mortality risk was significantly elevated only in patients with hypertension on one of two out-of-office measures.

Although white-coat hypertension (elevated blood pressure [BP] on office measurement with normal BP on out-of-office measurement) has been known for many years, its importance and role in management decisions remain unclear. In the PAMELA study, 2051 residents of a town in northern Italy underwent three different BP measurements: in an office, self-administered at home, and 24-hour ambulatory monitoring. Participants were characterized as having normotension (all 3 measures normal), sustained hypertension (all 3 measures elevated), or white-coat hypertension (elevated office measure and ≥1 normal out-of-office measures). The white-coat–hypertension group was subdivided into participants with normal values on both out-of-office measures (true white-coat hypertension) and those with an elevated value on one measure (partial white-coat hypertension). During an average of 16 years of follow-up, rates of cardiovascular and all-cause mortality increased progressively and significantly from normotension to white-coat hypertension to sustained hypertension. Compared with normotensive participants, rates of cardiovascular and all-cause mortality were significantly increased in participants with sustained hypertension and those with partial white-coat hypertension, but not in those with true white-coat hypertension. Results were similar after excluding participants receiving antihypertensive treatment. In 750 patients without sustained hypertension at baseline who underwent repeat measurements at 10 years, the rate of sustained hypertension increased progressively and significantly from normotension to true white-coat hypertension to partial white-coat hypertension. COMMENT In this study, the mortality risk associated with true white-coat hypertension was similar to that associated with normal blood pressure, whereas the risk associated with partial white-coat hypertension was comparable to that associated with sustained hypertension. These findings suggest that three forms of BP measurement (1 in-office, 2 out-of-office) are better than two for risk assessment in patients with white-coat hypertension.