Age Related Normative Changes in Phasic Orthostatic Blood Pressure in a Large Population Study: Findings From the Irish Longitudinal Study on Ageing (TILDA)
In beat-to-beat blood pressure (BP) methods, what is the distribution of phasic BP behavior, and how do gender and age impact patterns of BP and heart rate (HR) during postural change?
This was a retrospective analysis of data from TILDA (The Irish Longitudinal Study on Ageing), a prospective cohort study of community-dwelling adults ages ≥50 years in the Republic of Ireland. Participants had a health center assessment in which beat-to-beat BP measurements were recorded. Specifically, BP responses to orthostasis were recorded using the volume clamp method, combined with physical and brachial artery waveform reconstruction. Abnormal beat-to-beat variations in BP were categorized as follows: impaired BP stabilization (defined at each time point after standing as a value that is lower than the fifth percentile of the systolic BP [SBP] or diastolic BP [DBP] responses 60 seconds after standing in those ages 50-59 years), initial orthostatic hypotension (IOH) (symptomatic SBP drop ≥40 mm Hg or DBP drop ≥20 mm Hg within 15 seconds of active standing), and orthostatic hypotension (OH) (sustained SBP drop of ≥20 mm Hg or DBP ≥10 mm Hg on standing). The prevalence of impaired BP stabilization (OH(t)), IOH, and OH were reported by age, gender, and time elapsed after standing.
Of 8,175 participants recruited to the TILDA study, 5,037 agreed to a health center assessment (response rate = 62.0%). The analytic sample with complete active stand data was 4,475 participants. The overall prevalence of impaired BP stabilization was 15.6% (95% confidence interval [CI], 14.1-17.1); there were age-related differences with 41.2% (95% CI, 30.0-52.4) of those ages >80 years exhibiting impaired BP stabilization. OH impacted 6.9% (95% CI, 5.9-7.8) of the total population and 18.5% (95% CI, 9.0-28.0) of the >age 80 population. BP responses were characterized by specific age-related BP stabilization profiles; while orthostatic BP responses in adults ages 50-59 years stabilized within 30 seconds of standing, older groups took 30 seconds or longer.
Impaired BP stabilization and OH are common in an aging population, and there are significant age-related variations in BP stabilization profiles.
This is an important study that draws attention to the very significant prevalence of OH and impaired BP stabilization, particularly in older individuals. The authors used beat-to-beat data collected during an active stand; the feasibility and/or cost-effectiveness of collection of such data will need to be established. Nonetheless, the reference values for abnormal BP responses to standing that the authors have established may prove useful in diagnosis and treatment.
Clinical Topics: Vascular Medicine
Keywords: Hypotension, Orthostatic, Brachial Artery, Dizziness, Aging, Reference Values, Blood Pressure, Confidence Intervals, Posture, Ireland
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