Measurement of Blood Pressure in the Office

The widely accepted cut-point for normal blood pressure (BP) in the office setting evolved over several decades, based on data derived from a variety of sources. The Actuarial Society of America was one of the first organizations to publish BP data on thousands of community residents, followed by other classic studies such as Framingham, Western Electric Company, Kaiser Permanente, and the Multiple Risk Factor Intervention Trial.1,2 In every instance, BP readings were based on measurements taken by specially trained health professionals following guidelines for proper BP measurement. As a result of these and other population studies examining the association between different BP levels and cardiovascular outcomes, the importance of systolic and diastolic hypertension was recognized and an office BP of 140/90 mm Hg became the universally established cut-point for separating normal BP from hypertension. There are robust scientific data to support the use of 140/90 mm Hg to define hypertension in clinical practice guidelines. However, the guidelines do not take into account widely recognized problems associated with the quality of manual BP measurement in routine clinical practice.3 More recent recommendations4 for diagnosing hypertension clearly acknowledge that an increase in BP attributable to the “white coat response” is frequently associated with manual BP recordings performed in community-based practice. In recognizing this limitation of manual office BP, some guidelines have gone so far as to recommend that home BP and 24-hour ambulatory BP monitoring (ABPM) may need to be performed to obtain an accurate measure of a patient’s BP status. The greater reliance on 24-hour ABPM and home BP in the diagnosis and management of hypertension is the result of numerous clinical outcome studies5,6 that show that these measurement techniques are better predictors of cardiovascular events when compared to manual BP readings, even when manual readings are taken …