Background: Orthostatic hypotension (OH) is traditionally defined as a decline in systolic or diastolic blood pressure of >20 or >10 mm Hg, respectively, after 1 or 3 minutes of upright posture. OH is common in the elderly, but has not been consistently demonstrated to be an independent risk factor for falls in nursing home residents. Previous studies have used the standard definition of OH in assessing fall risk. No study has sought to determine if the timing of postural changes in blood pressure adds prognostic value; if changes in systolic, diastolic, or mean blood pressure are equivalent in predicting subsequent falls; and what degree of decline in blood pressure has the best predictive value.
Objective: We sought to define the timing and degree of orthostatic changes in blood pressure in a cohort of elderly nursing home residents during active standing and to explore the relationship to subsequent falls to test the hypothesis that orthostatic changes in blood pressure with noninvasive beat-to-beat technology would predict falls in nursing home residents better than the standard definition of OH.
Methods: One hundred eleven elderly (88 +/- 7 years) residents of a long-term care facility had measurement of orthostatic blood pressure changes during active standing for up to 3 minutes with a real-time continuous, noninvasive beat-to-beat blood pressure device. Falls were determined prospectively over a median follow-up period of 270 days (range, 8-657 days). The degree and timing of declines in systolic, diastolic, or mean blood pressure and their association with subsequent falls was determined using a time-to-event analysis.
Results: Forty-six subjects (41%) fell. The standard definition of OH was not predictive of subsequent falls (hazard ratio 1.03 at 1 minute and 1.32 at 3 minutes, P = not significant). Other measures of orthostatic blood pressure changes were also not associated with a significant increase in risk for subsequent falls, including declines in blood pressure within the first minute of standing.
Conclusion: The standard definition of OH was not an independent predictor of falls in frail nursing home residents. A one-time measure for the presence of postural hypotension using beat-to-beat tonometry was not predictive of fall risk. The timing and degree of orthostatic changes in blood pressure does not significantly enhance risk prediction for falls.