Comparing radial and brachial blood pressure measurements among people with large arm circumference: MACS/WIHS Combined Cohort Study

Recently, radial blood pressure cuffs have been developed for use among individuals with large arm circumferences although unique hypertension thresholds for radial assessment are not defined. We compared systolic and diastolic blood pressure measured from the upper arm and forearm among individuals with obesity. In a sub-study of participants who were living with HIV and without HIV with upper arm circumference > 40 cm ( n = 88, 2022–2023) in the Multicenter AIDS Cohort Study/Women’s Interagency HIV Study-Combined Cohort Study, both brachial and radial BP were measured with an automated monitor using a thigh cuff and a forearm cuff, respectively. Among 88 participants, 81% were female, 90% were Black, and 72% were living with HIV. The correlation between radial and brachial measurements was 0.60 for systolic and 0.69 for diastolic blood pressure. Average radial values were higher than brachial values for both systolic (16.5 mmHg higher: 148.3 versus 131.8 mmHg, p < 0.001) and diastolic (13.2 mmHg higher: 85.2 versus 72.0 mmHg, p < 0.001) blood pressure. When measured in the same participants, radial blood pressure was substantially higher than brachial blood pressure. When measuring radial blood pressure, a different threshold for hypertension diagnosis or use of a model to estimate brachial blood pressure may be needed.