Short- and long-term incidence of stroke in white-coat hypertension

White-coat hypertension (WCH) has been associated with a low risk for stroke, but long-term data are scanty. We analyzed individual data from 4 prospective cohort studies from the United States, Italy, and Japan that used comparable methodology for 24-hour noninvasive ambulatory blood pressure monitoring (ABPM). Overall, 4406 subjects with essential hypertension and 1549 healthy normotensive controls who were untreated at the time of initial ABPM were followed for a median of 5.4 years up to censoring or occurrence of a first stroke. At entry, mean age of subjects was 56 years ( range 18 to 97). Prevalence of WCH was 9%. During follow-up, there were 213 new cases of stroke. Stroke rate ( x 100 person years) was 0.35 in the normotensive group, 0.59 in the WCH group, and 0.65 in the group with ambulatory hypertension. In a multivariate analysis, the adjusted hazard ratio for stroke was 1.15 (95% confidence interval [CI], 0.61 to 2.16) in the WCH group ( P = 0.66) and 2.01 ( 95% CI, 1.31 to 3.08) in the ambulatory hypertension group ( P = 0.001) compared with the normotensive group. After the sixth year of follow-up, the incidence of stroke tended to increase in the WCH group, and the corresponding hazard curve crossed that of the ambulatory hypertension group by the ninth year of follow-up. In conclusion, WCH was not associated with a definitely increased risk of stroke during the total follow-up period. However, WCH might not be a benign condition for stroke in the long term.