Clinical relevance of double-arm blood pressure measurement and prevalence of clinically important inter-arm blood pressure differences in Indian primary care

Hypertension guidelines recommend measuring blood pressure (BP) in both arms at least once. However, this is seldom done due to uncertainties regarding measurement procedure and the implications of finding a clinically important inter-arm BP difference (IAD). This study aimed to provide insight into the prevalence of clinically important IADs in a large Indian primary care cohort. A number of 134 678 (37% female) unselected Indian primary care participants, mean age 45.2 (SD 11.9) years, had BP measured in both arms using a standardized, triplicate, automated simultaneous measurement method (Microlife WatchBP Office Afib). On average, there were clinically minor differences in right and left arm BP values: systolic BP 134.4 vs 134.2 mmHg (p < .01) and diastolic BP 82.7 vs 82.6 mmHg (p < .01), respectively. Prevalence of significant mean systolic IAD between 10 and 15 mmHg was 7,813 (5.8%). Systolic IAD ≥ 15 mmHg 2,980 (2.2%) and diastolic IAD ≥ 10 mmHg 7,151 (5.3%). In total, there were 7,595 (5.6%) and 8,548 (6.3%) participants with BP above the 140/90 mmHg threshold in only the left or right arm, respectively. Prevalence of participants with elevated BP on one arm only was highest in patients with a systolic IAD ≥ 15 mmHg; 19.1% and 13.7%, for left and right arm, respectively. This study shows that a substantial prevalence of IAD exists in Indian primary care patients. BP is above the diagnostic threshold for hypertension in one arm only for 6% of participants. These findings emphasize the importance of undertaking bilateral BP measurement in routine clinical practice.