Abstract

BACKGROUND: Functional status may be useful for identifying older adults who benefit from lower blood pressure. We examined whether functional status modifies the effect of antihypertensive treatment among older adults. METHODS: Post hoc analyses of the Systolic Hypertension in the Elderly Program (SHEP), a randomized trial of antihypertensive therapy vs. placebo (1985-1991) in 4,736 adults aged 60 years or older with isolated systolic hypertension. Outcomes were all-cause death, cardiovascular (CV) death, myocardial infarction (MI), stroke, falls, and symptoms of hypotension. The effect modifier of interest was functional status, assessed by self-reported physical ability limitation (PAL). RESULTS: Among persons with no PAL, those receiving treatment had a lower rate of death, CV death, and MI compared with placebo (4.0, 2.9, and 4.2 per 1,000 person-years lower, respectively). In contrast, among persons with a PAL, those receiving treatment had a higher rate of death, CV death, and MI compared with placebo (8.6, 5.3, and 2.7 per 1,000 person-years higher, respectively). These patterns persisted in Cox models, although interaction terms did not reach statistical significance. Treatment remained protective for stroke regardless of functional status. The rate of falls associated with treatment differed by functional status; incidence-rate ratio = 0.81, 95% confidence interval (CI) = (0.66, 0.99), and 1.32, 95% CI = (0.87, 2.00) in participants without and with a PAL, respectively, in models adjusted for demographics and baseline blood pressure (P-value for interaction, 0.04). CONCLUSIONS: Functional status may modify the effect of antihypertensive treatment on MI, mortality, and falls, but not stroke, in older adults. Functional status should be examined in other trial settings.