Abstract P007: Timing Of Orthostatic Hypotension And Its Relationship With Falls In Older Adults

Abstract

Background: There is inconsistent evidence on the optimal time after standing to assess orthostatic hypotension (OH). Objectives: To characterize the timing of OH after standing in older adults and the fall risk associated with OH at specific times. Methods: We performed a secondary analysis of the Study to Understand Fall Reduction and Vitamin D in You (STURDY). Blood pressure (BP) was measured in the supine position. Participants stood upright and underwent 6 standing BP measurements: 3 (M1-M3) immediately after standing, and 3 (M4-M6) after 3 minutes of standing. OH was defined as a decrease from supine systolic BP (SBP) of 20 or supine diastolic BP (DBP) of 10 mm Hg. We used generalized estimating equations to characterize changes in SBP, DBP, and OH over time. We used Cox models to examine the relationship between OH at each time point and subsequent falls. Results: There were 425 falls among 491 adults with 6,055 BP measurements and a median follow-up of 275 days. SBP/DBP decreased by a mean 9.5/2.6 mm Hg immediately after standing (M1) vs. 2.2/0.9 about 5 minutes after standing (M6). OH was observed in 32% of assessments at M1, and only 16% at M5 and M6 ( Table ). Only OH at M5 (Hazard Ratio = 1.84 [95% confidence interval = 1.17, 2.91]) and M6 (1.85 [1.03, 2.91]) predicted higher fall risk among individual time points. However, average OH from early (M1-3) and late (M4-6) measurements, respectively, also predicted higher fall risk (M1-3 = 1.65 [1.08, 2.52]; M4-6 = 1.73 [1.03, 2.91]). Conclusions: OH was most prevalent immediately after standing, but most informative for fall risk in late and average measurements. Multiple standing BP measurements may improve the clinical assessment of OH.