Am Fam Physician. 2012;86(9):online
Clinical Question: Is an automated measure of systolic blood pressure more predictive of home blood pressure than manual measure?
Bottom Line: The use of an automated blood pressure measurement, with the patient alone in an examination room, provides readings closer to ambulatory measures and eliminates the "white-coat hypertension" that occurs when physicians take a patient's blood pressure. (Level of Evidence: 1b)
Reference: Myers MG, Godwin M, Dawes M, et al. Conventional versus automated measurement of blood pressure in primary care patients with systolic hypertension: randomised parallel design controlled trial. BMJ 2011;342:d286.
Study Design: Randomized controlled trial (nonblinded)
Funding Source: Government
Setting: Outpatient (primary care)
Synopsis: Blood pressure measurement, if done exactly right, takes 14 minutes -- a far cry from time it takes to do a typical office-setting measurement. As a consequence, blood pressure measurements in the office are often spuriously raised and not representative of a patient's blood pressure the other 23.95 hours of the day. The Canadian investigators conducting this study enrolled 555 patients of 67 family medicine practices. The practices, not the patients, were randomized into a group that used either automated office blood pressure measurement or typical, manual blood pressure measurement for patients with pre-established systolic hypertension, either treated or not treated. Physicians in the manual blood pressure group were not given specific instruction on technique. Results from both groups were compared with awake blood pressures measured with a 24-hour ambulatory blood pressure monitor. The automated measurement was closer to ambulatory measurement for systolic but not diastolic blood pressure, overestimating blood pressure by an average 2.3 mmHg as compared with 6.5 mmHg for the manual measurement (P = .006). Diastolic blood pressure differences were similar in both groups. Part of the issue is the presence of the physician; average readings dropped significantly with the automated measurement after the physician left the room.