Mechanisms of Blood Pressure Measurement Inaccuracy: A Comparative Analysis of the Role of Occupation and Attire

Objectives: White coat hypertension (WCH) is defined as high blood pressure (BP) when measured by health care providers in medical environments, but normal BP in other settings. In this study, we examine the effects of occupation and attire on the accuracy of BP readings and WCH. Methods: 50 individuals were recruited and had their BP assessed twice by a cardiologist, a cardiac nurse, and a cardiovascular technician, once wearing a white lab coat, and once without, in random order. All individuals underwent a 24 hour ambulatory BP monitoring (ABPM). The mean of the daytime measurements of the ABPM served as the control. Results: Compared to the ABPM, the cardiologist recorded a 23.7 mm Hg higher systolic BP reading wearing a white coat and 13.3 mmHg without a white coat (p<0.0001). The cardiac nurse recorded a 14.2 mmHg higher reading with a white coat and 5.7 mmHg without a white coat (p<0.0001). There was no statistically significant difference between the measurements of the cardiovascular technician and the ABPM with a white coat, 2.8 mmHg, or without a white coat, -1.8 mmHg. Conclusions: This study demonstrates that the incidence of WCH and BP measurement inaccuracy occurs more frequently when assessed by a cardiologist or nurse than when assessed by a cardiovascular technician. Wearing a white coat aggravates blood pressure measurement inaccuracy. It may be advisable for healthcare providers to avoid wearing white lab coats or attire that identifies their occupation when measuring blood pressure.