Anxiety and outcome expectations predict the white-coat effect

ObjectiveTo determine whether elevated clinic blood pressure compared with daytime ambulatory blood pressure, referred to as the white-coat effect, is associated with anxiety and increased blood pressure expectancy in the doctor's office. MethodsThe 24-h ambulatory blood pressure measurements and physicians' blood pressure measurements were obtained in 226 normotensive and hypertensive study participants. Anxiety levels were assessed multiple times during the clinic visit using a Visual Analog Scale. Participants' expectations regarding the clinic visit were assessed using a six-item scale (Expectations of Outcomes Scale). The white-coat effect was computed as the difference between the mean clinic blood pressure and the mean daytime ambulatory blood pressure. Multiple regression analysis was performed to examine the association between anxiety, outcome expectations and the white-coat effect, adjusting for age, sex, and ambulatory blood pressure level. ResultsAs predicted, outcome expectations and anxiety during the clinic visit were significantly associated with the white-coat effect. Results of the regression analysis indicated that only expectancy had an independent effect on the systolic white-coat effect; however, both anxiety and expectancy had independent effects on the diastolic white-coat effect. ConclusionOur results provide empirical support to the hypothesis that anxiety and blood pressure expectancy may elevate clinic blood pressure.