A white coat response which increases BP when recorded in clinical practice has been recognized as a cause of apparent hypertension. Automated office (AO) BP measurement was developed to improve the accuracy of office BP. By recording multiple readings using an automated sphygmomanometer with the patient resting quietly alone, the white coat response which averaged 15 mmHg was eliminated, with AOBP being similar to the awake ambulatory (A) BP. In a Spanish study of 27,211 patients in the community, the difference between awake ambulatory BP and routine office BP was even greater (25 mmHg). Based on these studies, Canadian and American guidelines now recommend AOBP as the preferred method for recording BP in the office.
However, European guidelines continue to focus on improving the accuracy of office BP by stricter adherence to proper BP measurement technique. AOBP is considered to be impractical, with concerns that readings take too long, require a dedicated room and lack support from longitudinal outcome studies. In reality, none of these criticisms are valid. Guidelines on the proper measurement of BP in the office have been published as far back as 1939, yet, there has never been a meta-analysis showing that routine office BP is as good a predictor of cardiovascular outcome as the BP recorded under research conditions.
Awake ABP is a gold standard for determining the risk of future cardiovascular morbidity and mortality. In 19 research studies, mean systolic AOBP was only 0.3 mmHg different from the mean awake ABP. When data comparing attended versus unattended AOBP in research studies were analysed, the mean systolic attended AOBP was still 6 mmHg higher. The presence of office staff appears to be sufficient to increase office BP.
AOBP has been criticized for being too variable. In a recent study comparing AOBP to home BP readings, both types of measurements exhibited similar degrees of variability, yet only home BP is recommended as an alternative to 24-hour ABPM. This conclusion ignores data showing mean AOBP, home BP and awake ABP being similar.
Guidelines for clinical practice should be evidence-based. It may not be possible to record AOBP on every patient. However, AOBP readings should be recommended as the optimum method for recording BP in routine clinical practice, whenever it is feasible to do so.