Influence of the hospital environment and presence of the physician on the white-coat effect

OBJECTIVE: To determine the separate contribution of the physician and the hospital environment to differences between home (HBP) and office BP (OBP). METHODS: For 3 consecutive days, 65 hypertensive patients measured their HBP. OBP was determined with the same device by the physician. A higher OBP than HBP was regarded as white-coat effect (WCE), whereas lower OBP than HBP was regarded masked effect. OBP was measured automatically before, during and after the presence of the physician. The physician effect was the BP rise caused by the entrance of physician. The WCE minus the physician effect was regarded the hospital's contribution to the BP differences (hospital effect). We assessed the magnitudes of the hospital effect and the physician effect in determining the WCE. Furthermore, we assessed the correlation of these BP phenomena with each other, and with clinical variables. RESULTS: The WCE consisted of 4.6/-1.7 +/- 9.9/10.9 mmHg hospital effect and of 4.4/3.4 +/- 6.6/3.3 mmHg PE. The masked effect consisted of a substantially larger hospital effect (19.6/9.4 +/- 12.7/9.5 mmHg) than physician effect (4.6/3.0 +/- 6.4/3.9 mmHg). Physician effect did not correlate with systolic or diastolic WCE or masked effect (r = -0.05 to 0.08, P > 0.39). In regression analysis, age, baseline mean arterial pressure and BMI were not significantly associated with WCE (all P values >0.4). CONCLUSION: BP differences between home and office can largely be attributed to the hospital environment rather than to the entrance of the physician. The physician-related BP effect is not related to differences of HBP and OBP