An obstacle to wider adoption of the repeated automated office-based blood pressure (AOBP) is the guidelines that suggested a 60-120 seconds time period. A three-day assessment was conducted on patients from a single hypertension center. It included 24-hour ambulatory blood pressure (BP) monitor (ABPM) and one of two nonrandomized, unattended AOBP protocols. About 50% of the patients went through three AOBP measurements within a 30-second interval. The other 50% went through three BP measurements within a 60-second interval. The researchers compared the average awake-time BP from ABPM and the first AOBP measurement with all the accumulated measurements.
They utilized a linear regression to determine if the 30-second protocol was associated with an individual or average AOBP measurements or awake-time ABPM. They also used an interaction term to decide if interval altered the association between AOBP measurements (individual and mean) with awake-time ABPM. There were 102 patients (mean age, 59.2±16.2 years; 64% women; 24% Black). The measurements showed the average awake-time BP was 132.5±15.6/77.7±12.2 mm Hg among those who underwent the 60-second protocol and 128.6±13.6/76.5±12.5 mm Hg for the 30-second protocol. In the second and third AOBP measurements, the mean systolic and diastolic blood pressure was lower by −0.5/−1.7 mm Hg and −1.0/−2.3 mm Hg for the 60-second protocol against −0.8/−2.0 mm Hg and −0.7/−2.7 mm Hg for the 30-second protocol. Hence, the differences were not considerably altered by the protocol. Overall protocols, the variances between AOBP measures and awake-time ABPM were closely identical.
Taking everything into account, the half-minute interval was as precise and reliable as the one-minute interval. So, AOBP seemed more reasonable in clinical practice as supported by the observations in the study.