Impact of Clinic-Based Blood Pressure Approaches on Blood Pressure Measurement.

backgroundClinic-based blood pressure (BP) is a closely-tracked metric of health care quality, but is prone to inaccuracy and measurement imprecision. Recent guidelines have advocated for automated office blood pressure (AOBP) devices to improve clinic-based BP assessments.

methodsPatients from a single hypertension clinic underwent a 3-day evaluation that included a 24-hour ambulatory blood pressure monitoring (ABPM), 2 manual clinic-based BP measurements (over 2 visits), and an unattended AOBP measurement (single visit). All measurements were compared to the average wake-time systolic BP (SBP) and diastolic BP (DBP) from ABPM.

resultsAmong 103 patients (mean age 57.3 ± 14.8 years, 51% women, 29% black) the average wake-time SBP was 131.3 ± 12.3 mm Hg and DBP was 78.3 ± 9.2 mm Hg. The average of 2 manual BPs was significantly higher than wake-time ABPM with mean differences of 5.5 mm Hg (P < 0.001) for SBP and 2.7 mm Hg (P = 0.002) for DBP. In contrast, the averages of the last 2 AOBP measurements did not significantly differ from ABPM with mean differences of 1.6 mm Hg (P = 0.21) for SBP and -0.5 mm Hg (P = 0.62) for DBP. The estimated prevalence of SBP ≥ 140 or DBP ≥ 90 mm Hg based on wake-time ABPM was 27.2% vs. 49.5% based on the average of 2 manual measurements (difference 22.3%; P < 0.001) and 31.1% based on the average of the last 2 AOBP measurements (difference 3.9%; P = 0.57).

conclusionsA single visit, unattended AOBP more precisely estimated BP and the prevalence of stage 2 and uncontrolled hypertension than even the average of 2 manual clinic visits, supporting guideline recommendations to use AOBP for clinic-based BP measurements.