Improper Arm Position When Measuring BP Can Overestimate Readings

TUESDAY, Oct. 8, 2024 (HealthDay News) — Commonly used arm positions (lap and side) for measuring blood pressure (BP) can overestimate readings, according to a study published online Oct. 7 in JAMA Internal Medicine.

Hairong Liu, from the Johns Hopkins Bloomberg School of Public Health in Baltimore, and colleagues conducted a crossover randomized clinical trial involving 133 adults aged 18 to 80 years in Baltimore to examine the effect of different arm positions on BP readings. Participants were randomly assigned to sets of triplicate BP measurements with the arm positioned supported on a desk, supported on the lap, and unsupported at the side (desk 1 [reference], lap, and side). A fourth BP measurement was undertaken with the arm supported on a desk (desk 2) to account for intrinsic BP variability.

The researchers found that the lap and side positions yielded significantly higher BP readings than desk positions, with difference-in-differences of 3.9 and 4.0 mm Hg, respectively, in systolic and diastolic BP for the lap position and 6.5 and 4.4 mm Hg, respectively, for systolic and diastolic BP for the side position. Across subgroups, the patterns were generally consistent.

“Not adhering to the guideline-recommended arm position and support during BP measurement can result in overestimation of BP by 4 to 10 mm Hg,” the authors write. “This degree of BP error could lead to a substantial number of people being overdiagnosed with hypertension.”

One author disclosed financial ties to Kowa Company, RhythmX AI, and Fukuda Denshi.

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