A proposed algorithm for diagnosing hypertension using automated office blood pressure measurement

Abstract

To validate an algorithm for the interpretation of automated office blood pressure (AOBP) measurement based upon data from untreated patients referred by physicians in the community for 24-h ambulatory blood pressure monitoring (ABPM). An algorithm for interpreting AOBP readings was developed taking into account the previously documented equivalence of AOBP and mean awake ambulatory BP (ABP; mmHg), which were each classified as optimum BP (<130/80), borderline BP (130-139/80-89) and hypertension (>or=140/90). This classification was applied to data derived from 254 untreated patients undergoing 24-h ABPM, AOBP and routine manual BP taken at the patient's own family physician's office. The mean awake ABP (135.3 +/- 12.4/81.0 +/- 10.2) was similar to the mean AOBP (132.6 +/- 17.4/80.0 +/- 11.1) with both values being significantly (P < 0.001) lower than the routine manual BP (149.7 +/- 15.2/89.3 +/- 9.5). Of the 69 patients with a systolic AOBP at least 140, only five (7.3%) exhibited white-coat hypertension with a normal mean awake ambulatory systolic BP less than 130. Similarly, of the 47 patients with a diastolic AOBP at least 90, none had optimum BP (diastolic BP < 80 mmHg on ABPM). White-coat hypertension was significantly (P = 0.005/P = 0.006) more prevalent for systolic/diastolic BP (22.1%/13.4%) when routine, manual BP readings were analysed. In contrast to routine manual office BP, a diagnosis of hypertension by AOBP is unlikely to be associated with an optimum awake ABP.