A CME Journal For Family Physicians


Initial BP Measurements are Often Misleading

In primary care, initial blood pressure (BP) measurements can often be misleading and reflect a BP that is higher than it really is, according to new study findings.
With this in mind, the authors of the study emphasize the importance of taking a second BP measurement at the same clinic visit with at least 1 minute between BP readings, which the American Heart Association has recommended in the past.
The authors noted that only about 54% of patients with hypertension seen in primary care have controlled BP, which can be impacted by BP measurement error—including inappropriate cuff size, talking during measurement, terminal digit preference, and incorrect arm and body positioning.
For their study, the researchers evaluated data on 38,260 patients with hypertension who made 80,864 primary care office visits between January 1 and December 31, 2016. Advisory alerts were introduced into electronic health records (EHRs) to remind clinicians to remeasure BP when the initial measurement was elevated (defined as at least 140/90 mm Hg).
Results indicated that the initial BP was found to be elevated in at least 31,531 (39%) visits, and an initially elevated BP was remeasured during 26,089 (83%) visits.
Ultimately, the researchers found that 9358 (36%) of patients with a repeated BP measurement had second readings that were lower than 140/90 mm Hg. Patients whose BP was closest to the threshold of 140/90 mm Hg had higher odds of BP control with repeated measurements.
Median change in systolic BP was -8 mm Hg between measurements, and change in systolic BP was found to be positively associated with the initial BP value.
Most notably, the researchers found that repeated measurement of an initially elevated BP was associated with an increase in the overall rate of hypertension control from 61% to 73% in this cohort.

Einstadter D, Bolen SD, Misak JE, et al. Association of repeated measurements with blood pressure control in primary care [Published online April 16, 2018]. JAMA Intern Med. doi:10.1001/jamainternmed.2018.0315