White-Coat Hypertension and Risk of Stroke

Abstract

The term “white-coat hypertension” (WCH; also commonly referred to as isolated office hypertension) describes the transient increase in blood pressure (BP), resulting from an alerting reaction and pressor response, observed in certain individuals when attending a clinic or doctors’ office.1 The diagnosis of WCH is usually ascribed when clinic BPs exceed 135/85 mmHg and average daytime BPs do not. WCH could be dismissed as a risk factor for stroke and other cardiovascular events, because the increase in BP is transient and may be idiosyncratic to the clinic setting.2 However, WCH may be a marker of stress reactivity per se, because surges in BP that occur in the doctor’s office are indicative of BP surges in other stressful scenarios.3 The article by Verdecchia et al featured in this edition of Hypertension 4 reports data from 6000 Italian, Japanese, and American adults. The purpose of the study was to explore the relationship between classically defined WCH and incident stroke during a median follow-up of 5.4 years. When compared with normotensive controls, a tendency for increased stroke incidence was observed in patients with WCH (unadjusted hazard ratio, 1.15). However, because the variance around the estimates of effect is large (95% confidence interval, 0.61 to 2.16), this association is not statistically significant, despite this study being the largest of its kind to date. By contrast, a statistically significantly association between ambulatory hypertension and stroke was observed (unadjusted hazard ratio, 2.01; 95% confidence interval, 1.31 to 3.08). The hypothesis that Verdecchia et al test is important because vessels in the brain may be particularly susceptible to transient elevations in BP. Furthermore, because WCH is highly prevalent,5 even a relatively small increase in stroke risk on an individual level could convey a high population-attributable risk. Although Verdecchia et al have demonstrated using …