Impairments in Hemodynamic Responses to Orthostasis Associated with Frailty: Results from TILDA19 Mar 2018
Background: Dysregulated homeostatic response to stressors may underlie frailty in older adults. Orthostatic hypotension results from impairments in cardiovascular homeostasis and is implicated in falls and other adverse outcomes. This study aimed to characterise the relationships between orthostatic BP and heart rate recovery and frailty in an older population. Design: Cross-sectional study. Setting: Two health centres in the Republic of Ireland. Participants: 4334 adults aged 50 and older enrolled in The Irish Longitudinal Study on Ageing. Measurements: Continuous non-invasive blood pressure (BP) responses during active standing were captured by Finometer®. Frailty was assessed using the Cardiovascular Health Study criteria. Linear mixed models (random intercept) with piecewise splines were used to model differences in the rate of BP and heart rate recovery. Results: 93 (2.2%) participants were frail and 1366 (31.5%) were prefrail. Adjusting for age and sex, frailty was associated with a reduced rate of systolic BP recovery between 10-20 seconds post stand (frailty*time = -4.12 95%CI: -5.53 - -2.72) and with subsequent deficits in BP between 20-50 seconds. Similar results were seen for diastolic BP and heart rate. Further adjustment for health behaviours, morbidities, and medications reduced, but did not attenuate these associations. Of the 5 frailty criteria, only slow gait speed was consistently related to impaired BP and heart rate responses in the full models. Conclusions: Frailty, and particularly slow gait speed, was associated with reduced rate of recovery in BP and heart rate recovery following active standing. Impaired BP recovery may represent a marker of physiological frailty.