Use of an automated blood pressure recording device, the BpTRU, to reduce the "white coat effect" in routine practice

Patients often exhibit higher blood pressure (BP) readings in the doctor's office, a phenomenon known as the white coat effect. This study examines the presence of a physician in the examining room as a possible factor in provoking a white coat effect.

Blood pressure measurements taken by an automated BP recording device, the BpTRU (VSM MedTech Ltd., Vancouver, BC, Canada) with the patient alone in the examining room, were compared with the following: (1) BP taken by the patient's family physician; (2) BP taken on the first visit to a hypertension specialist; (3) BP measured by a trained research technician and (4) the mean awake ambulatory BP (ABP). The BpTRU and trained research technician readings were taken outside of the office (treatment) setting in an ABP research unit.

Blood pressure readings (mm Hg, mean +/- SEM) taken by the BpTRU (155 +/- 5/88 +/- 2) tended to be lower than for the family physician (166 +/- 4/89 +/- 3) and the hypertension specialist (174 +/- 5/92 +/- 2; P <.001). However, BP taken by the trained research technician (158 +/- 4/90 +/- 2) was similar to the value obtained by the BpTRU. The mean awake ABP was lower (P < 0.01) than the other four BP values.

Use of an automated BP recording device outside of the office (treatment) setting can partly eliminate the white coat effect. A similar finding was observed with readings taken by a trained research technician under similar conditions. Referral of patients to nonoffice settings for automated BP recordings may provide a more accurate estimate of a patient's BP status, with partial elimination of the white coat effect associated with readings taken by a physician.