Impairments in Hemodynamic Responses to Orthostasis Associated with Frailty: Results from The Irish Longitudinal Study on Ageing (TILDA)

Abstract

Objectives: To characterize the relationships between orthostatic blood pressure (BP) and heart rate recovery and frailty in an older population.

Design: Cross-sectional study.

Setting: Two health centers in the Republic of Ireland.

Participants: The Irish Longitudinal Study on Ageing participants aged 50 and older (N=4,334).

Measurements: Continuous noninvasive BP responses during active standing were captured using digital photoplethysmography. Frailty was assessed using the Cardiovascular Health Study criteria. Linear mixed models (random intercept) with piecewise splines were used to model differences in rate of BP and heart rate recovery.

Results: Ninety-three (2.2%) participants were frail, and 1,366 (31.5%) were prefrail. Adjusting for age and sex, frailty was associated with a slower rate of systolic BP recovery 10 to 20 seconds after standing (frailty by time = -4.12, 95% confidence interval=-5.53 to -2.72) and with subsequent deficits in BP 20 to 50 seconds after standing. Similar results were seen for diastolic BP and heart rate. Further adjustment for health behaviors, 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 model.

Conclusion: Frailty, particularly slow gait speed, was associated with slower rate of BP and heart rate recovery after active standing. Impaired BP recovery may be a marker of physiological frailty.

Keywords: aging; blood pressure; frailty; homeostasis; orthostatic hypotension.