In general practice, doctors record higher blood pressures in the presence of students

The authors of the interesting review come to the conclusion that the white coat effect is greater for blood pressure measurements made by doctors than by nurses.¹ In our trial, patients were randomised into a ‘trainee’ group (n = 133) and a ‘no trainee’ (n = 129) group. The blood pressure was measured at two subsequent contacts. In the ‘trainee’ group, a student was present at the first visit only. In the ‘no trainee’ group, both visits were without a student. At the first visit, systolic pressure was higher in the ‘trainee’ group than in the ‘no trainee’ (control group) (139.5 versus 133.1 mmHg, P = 0.004), with a similar trend for diastolic pressure (80.2 versus 77.8 mmHg, P = 0.07). From the first contact to the follow-up visit, blood pressure decreased in the trainee group by 4.8 mmHg systolic (P<0.001) and 1.7 mmHg diastolic (P = 0.03), whereas the corresponding changes in the control group were −0.1 mmHg (P = 0.90) and +1.5 mmHg (P = 0.03). Thus, the between group differences in these trends averaging 4.7 mmHg (95% CI = 1.5 to 7.9, P = 0.005) systolic and 3.2 mmHg (95% CI = 1.1 to 5.3, P = 0.003) diastolic were statistically significant. We concluded that in teaching-practices, the presence of a doctor-in-training has a significant pressor effect when an experienced GP measures a patient’s blood pressure.² If confirmed, the findings imply that doctors should be cautious to initiate or adjust antihypertensive treatment when blood pressure readings are obtained in the presence of a student.