Background: orthostatic hypotension may be an important risk factor for falls, though this has not yet been demonstrated in prospective studies. This may be because conventional methods of measuring blood pressure changes are too imprecise and not optimally timed.
Objectives: to determine whether changes in blood pressure induced by upright tilt are associated with falls in older people, and whether medication use and symptoms of dizziness are associated with blood pressure changes and falls.
Methods: seventy men and women aged 62-92 years participated. We measured blood pressure with a plethysmograph monitor continuously before and after upright tilt. We recorded medication use and symptoms of dizziness in response to the tilt. Subjects were then followed up for 12 months to determine the incidence of falls.
Results: subjects who fell in the follow-up period had significantly greater decreases in systolic blood pressure when tilted than those who did not fall. Furthermore, those who had unstable systolic blood pressure during the 3 minutes after tilting, in addition to large blood pressure drops, had a two-fold increased risk of falling compared with those with neither of these conditions. Symptoms of dizziness on tilting were uncommon and not associated with blood pressure or heart rate changes, medication use, or falls incidence. Antidepressant and antihypertensive medication use were associated with decreases in diastolic rather than systolic blood pressure, but were not associated with falls.
Conclusions: these findings indicate that both the decrease in blood pressure and the unstable nature of the blood pressure response following upright tilt are useful predictors of falls in older people.