Sit-up test for assessing impaired blood pressure regulation in community-dwelling older adults: a cross-sectional study.

Background: The sit-up test enables safe orthostatic hypotension assessment without using a tilt table in high fall-risk individuals; however, no study has compared blood pressure responses between older adults with and without orthostatic hypotension during this test. The primary objective was to compare blood pressure responses during the sit-up test between community-dwelling older adults with and without orthostatic hypotension as defined by this test. The secondary objective was to determine the associations between orthostatic hypotension detected by the sit-up test and adverse health outcomes in these individuals.

Methods: This was a cross-sectional study; thus, it cannot establish causality. One hundred two community-dwelling older adults underwent the sit-up test. Orthostatic hypotension was defined as a decrease of ≥ 10 mmHg in systolic blood pressure and/or ≥ 5 mmHg in diastolic blood pressure during the test. Supine and seated hypertension were defined as systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg. Blood pressure responses during the test were compared between participants with and without orthostatic hypotension. Moreover, independent associations between orthostatic hypotension and adverse health outcomes were examined.

Results: Thirty-four participants (33.3%) experienced orthostatic hypotension. Participants with orthostatic hypotension demonstrated a greater decrease in systolic blood pressure (F_(3,297) = 47.0, p < 0.001), smaller increase in diastolic blood pressure (F_(3,297) = 26.5, p < 0.001), and higher supine systolic blood pressure (t = 3.363, p = 0.005) than those without orthostatic hypotension. Accordingly, 52.9% of the participants with orthostatic hypotension had supine hypertension. Orthostatic hypotension was associated with a higher proportion of participants with at least one comorbidity (odds ratio = 4.50, p = 0.002) and those with a pre-frail or frail status (odds ratio = 3.08, p = 0.022), even after adjusting for supine and seated hypertension.

Conclusion: Community-dwelling older adults with orthostatic hypotension were characterized by an impaired increase in diastolic blood pressure during sitting up and high supine systolic blood pressure. Orthostatic hypotension was associated with adverse health outcomes, independent of supine and seated hypertension. These findings provide valuable insights for the application of the sit-up test in preventive health screenings for older adults.