Hostility explains some of the discrepancy between daytime ambulatory and clinic blood pressures.

The authors examined whether hostility explained the discrepancy commonly observed between clinic and daytime ambulatory blood pressures. Daytime ambulatory blood pressure (DABP) was assessed every 45 min over 6 days in healthy adults (N = 120). After controlling for demographic variables, time-varying covariates such as position and activity level, and clinic blood pressure (CBP), the Cook-Medley Hostility Scale was significantly associated with daytime ambulatory diastolic blood pressure. No support was obtained for mediation by psychological factors. Discrepancies between DABP and CBP may be due, in part, to differences in the degree to which these 2 types of measures are associated with individual differences in hostility. These results suggest that the addition of hostility to CBP may improve its predictive power.