Blood pressure (BP) measured in the clinic is subject to the white coat effect and does not always indicate the 'usual' BP. Ambulatory BP is the current gold standard, but remains inconvenient for routine use. Interest in automated BP, where the healthcare professional is absent from the examination room during BP measurement, is growing, as this reduces the white coat effect and yields BP values that are close to ambulatory readings. The aim of this study was to investigate how well automated office BP (AOBP), measured using the Omron HEM-907 device, compares with observed office BP (OOBP, healthcare professional remains in the examination room) and awake ambulatory BP (AABP) measurements. OOBP, AOBP and AABP were measured in 108 participants, with OOBP and AOBP measurements repeated 1 week later, following a standardised protocol. Average BP readings for visit one were 134 ± 18/77 ± 11 for OOBP, 131 ± 16/75 ± 11 for AOBP, and 133 ± 15/82 ± 12 for AABP. On both visits, automated readings were significantly lower than observed readings for both systolic and diastolic BP (P < 0.001 for both). Automated readings were also significantly lower than ambulatory readings, with a mean difference in systolic/diastolic BP of - 2 ± 11/- 7 ± 10 (P < 0.001 for both), with high correlations between the two modalities (r = 0.75 and r = 0.64, for systolic and diastolic BP, respectively, P < 0.001 for both). AOBP measured by the Omron HEM-907 is not associated with a white coat effect, unlike observed readings, and provides reproducible results and good correlations with ambulatory readings. Automated BP measured using the Omron HEM-907 is, therefore, a useful alternative to observed office readings.
Keywords: Ambulatory blood pressure; Automated blood pressure; Hypertension; OMRON HEM-907.