Home blood pressure predicts stroke incidence among older adults with impaired physical function

Objective: Several observational studies have found modifying effects of functional status on the association between conventional office blood pressure (BP) and adverse outcomes. We aimed to examine whether the association between higher BP and stroke was attenuated or inverted among older adults with impaired function using self-measured home BP measurements. Methods: We followed 501 Japanese community-dwelling adults aged at least 60 years (mean age, 68.6 years) with no history of stroke. Multivariate-adjusted hazard ratios for 1-SD increase in home BP and office BP measurements were calculated by the Cox proportional hazards model. Functional status was assessed by self-reported physical function. Results: During a median follow-up of 11.5 years, first strokes were observed in 47 participants. Higher home SBP, but not office SBP, was significantly associated with increased risk of stroke among both 349 participants with normal physical function and 152 participants with impaired physical function [hazard ratio (95% confidence interval) per 14.4-mmHg increase: 1.74 (1.12–2.69) and 1.77 (1.06–2.94), respectively], with no significant interaction for physical function (P = 0.56). Higher home DBP, but not office DBP, was also significantly associated with increased risk of stroke (P ≤ 0.029) irrespective of physical function (all P > 0.05 for interaction). Neither home BP nor office BP was significantly associated with all-cause mortality irrespective of physical function. Conclusion: Higher home BP was associated with increased risk of stroke even among those with impaired physical function. Measurements of home BP would be useful for stroke prevention, even after physical function decline.