Attended vs unattended systolic blood pressure measurement: A randomized comparison in patients with cardiovascular disease

Recent clinical guidelines recommend lower blood pressure (BP) goals for most patients, and recent trends have favored use of automated unattended BP measurements in the office setting to minimize observer error and white-coat effects. Patients attending a routinely scheduled CVD clinic visit were prospectively randomized to BP measured using an attended, followed by an unattended method, or vice versa, after a controlled rest period. All study BP measurements were obtained in triplicate using the automated Omron HEM-907XL BP monitor, and averaged. The outcome was difference in SBP. Routinely measured clinic BP from the same visit was extracted from the medical record, and compared with attended and unattended BP. A total of 102 patients were randomized, and mean age was 63 years, 52% female and 75% Caucasian. Attended and unattended SBP was 125.4 ± 20.4 and 122.6 ± 21.0 mm Hg, mean ± SD, respectively. Routine clinic SBP was 130.6 ± 23.6 mm Hg. Attended SBP was 2.7 mm Hg higher than the unattended measurement (95% CI 1.3-4.1; P = .0002). Routine clinic SBP was 5.2 mm Hg higher than attended SBP (95% CI 2.4-8.0; P = .0003) and 8.0 mm Hg higher than unattended SBP (95% CI 5.4-10.5; P < .0001). Attended measurement of BP is significantly higher than unattended measurement and the difference is physiologically meaningful, even in a CVD cohort with generally well-controlled hypertension. Furthermore, routine clinic SBP substantially overestimates both attended and unattended automated SBP, with important implications for treatment decisions like dose and/or drug escalation.