Association between blood pressure and disability-free survival among community-dwelling elderly patients receiving antihypertensive treatment

A reduction of elevated blood pressure (BP) is an important treatment goal in elderly hypertensive patients. However, excessive reduction of systolic BP (SBP) and/or diastolic BP (DBP) might be harmful in such patients. We investigated whether this was the case with regard to risk of incident disability or death in community-dwelling elderly subjects. We analyzed 570 patients receiving antihypertensive treatment aged 65-94 years. The endpoint was the composite outcome of incident disability, defined as first certification of a support/care need or death. Relationships among each of the four classes of SBP or DBP and the risk of incident disability or death were estimated using the Cox proportional hazards model. Over four years, 77 (13.5%) incident disabilities or deaths occurred. After adjustment for age, sex and variables selected according to their univariate analysis P-value <0.20, the risk of events was significantly higher in subjects with baseline SBP < 120 mm Hg (hazard ratio (HR) = 2.81, P = 0.023) and >= 160 mm Hg (HR = 4.32, P<0.001), compared with subjects with baseline SBP of 140-159 mm Hg, who showed the lowest incidence of events. This J-curve relationship was observed in very elderly patients (>= 75 years) but not in younger patients. Patients with SBP < 120 mm Hg tended to have a higher risk of incident disability caused by cerebral events, and those with SBP >= 160 mm Hg had a higher risk of incident disability caused by falls/bone fractures. These observations indicate that excessive BP reduction could cause discontinuance of disability-free survival in community-dwelling elderly patients.