Background: Orthostatic hypotension (OH) is considered an important risk factor for falls, but prospective studies have been small and inconsistent.
Methods: We examined the association between OH assessed at baseline in 12,661 middle-aged participants of the ARIC Study (1987-1989). OH was considered present if there was a drop in blood pressure (systolic ≥20 mm Hg or diastolic blood pressure ≥10 mm Hg) when moving from the supine to standing position after three minutes. Changes in systolic or diastolic blood pressures were also examined as continuous variables. The outcome of interest was any fall identified from ICD9 discharge codes from hospitalization records or Centers for Medicare & Medicaid Services claims data. The association of OH and risk of fall was characterized using Cox proportional hazard models.
Results: At baseline, the mean age was 54 years; participants were 55% women and 47% black; 5% (N = 651) had OH. During a median follow-up of 23 years, there were 2,274 new falls. The incidence rate, using age as the time axis, was 2.8 per 1,000 person-years among participants with OH versus 2.3 per 1,000 person-years among those without OH (P = 0.03). OH was significantly associated with long-term risk of fall even after adjustment for demographics and other risk factors (Figure legend) (HR 1.25, 95% CI 1.04-1.49). Furthermore, postural change in diastolic blood pressure was more strongly associated with risk of falls (HR 1.07 per -5 mm Hg in diastolic blood pressure; P < 0.001) than postural change in systolic blood pressure (HR 1.02 per -5 mm Hg in systolic blood pressure; P = 0.01). This association appeared linear without evidence of a threshold effect (Figure).
Conclusions: In an ambulatory population, OH, and in particular, postural change in diastolic blood pressure, were significant, independent risk factors for falls over a long period of time. Future studies should determine whether targeted therapies can reduce falls in persons with OH.