Association of mortality with longitudinal changes in right- and left-arm blood pressure discrepancies among hypertensive adults.

It remains unclear whether poor cardiovascular outcomes are associated with the longitudinal changes in inter-arm blood pressure (BP) difference. We aimed to investigate the role of repeated BP measurement in bilateral arms in predicting all-cause mortality. A total of 27,147 hypertensive participants aged ≥18 years (56.6% women; mean age, 67.1 years) were selected from the basic public health system of Samming city and underwent repeated bilateral BP measurement at two health checkups in 2013 and 2018. Multivariable-adjusted Cox regression was used to relate future mortality with change in inter-arm BP difference. The absolute inter-arm difference ≥10 mmHg increased from 12.6 to 13.3% for systolic and 8.18 to 8.27% for diastolic BP over 5 years apart. When assessed using the dichotomous cutoff of 10 mmHg for inter-arm systolic/diastolic BP difference at two examinations, 76.1%/84.4% remained persistently low and 2.00%/0.87% persistently high, and 11.3%/7.40% of the participants changed from low to high and 10.6%/7.31% from high to low. During a median follow-up of 5.43 years, 1703 (6.27%) deaths occurred. Participants who had persistently elevated absolute values of inter-arm BP difference over 5 years were at higher risk for all-cause mortality with adjusted hazard ratios amounting to 1.47 (95% CI: 1.10-1.98; P = 0.010) for systolic BP and 1.68 (95% CI: 1.10-2.56; P = 0.016) for diastolic BP. Repeated bilateral BP measurement indicated that persistently increased absolute levels of inter-arm BP difference over time were associated with future mortality, highlighting that repeated bilateral BP measurements may provide additional risk information for hypertension management.