Long-term Individual and Population Functional Outcomes in Older Adults With Atrial Fibrillation

Anna L. Parks MD; Sun Y. Jeon MS PhD; W. John Boscardin PhD; Michael A. Steinman MD; Alexander K. Smith MD, MPH, MAS; Margaret C. Fang MD, MPH; Sachin J. Shah MD, MPH

Disclosures

J Am Geriatr Soc. 2021;69(6):1570-1578. 

In This Article

Abstract and Introduction

Abstract

Background: Older adults with atrial fibrillation (AF) have multiple risk factors for disablement. Long-term function and the contribution of strokes to disability have not been previously characterized. Our objective was to determine long-term function among older adults with AF and the relative contribution of stroke.

Methods: We used data from the nationally representative Health and Retirement Study (1992–2014) with participants ≥65 years with incident AF. We examined the association of incident stroke with three outcomes: independence with activities of daily living (ADL), instrumental activities of daily living (IADL), and residence outside a nursing home (community-dwelling). We fit logistic regression models with repeated measures adjusting for comorbidities and demographics to estimate the effect of stroke on function. We estimated the contribution of strokes to the overall population burden of disability using the method of recycled predictions.

Results: Among 3530 participants (median age 79 years, 53% women), 262 had a stroke over 17,396 person-years. Independent of stroke and accounting for comorbidities, annually, ADL independence decreased by 4.4%, IADL independence decreased by 3.9%, and community dwelling decreased by 1.2% (p < 0.05 for all). Accounting for comorbidities, of those who experienced a stroke, 31.9% developed new ADL dependence, 26.5% developed new IADL dependence, and 8.6% newly moved to a nursing home (p < 0.05 for all). Considering all causes of function loss, 1.7% of ADL disability-years, 1.2% of IADL disability-years, and 7.3% of nursing home years could be attributed to stroke over 7.4 years.

Conclusion: Older adults lose substantial function over time following AF diagnosis, independent of stroke. Stroke was associated with a significant functional decline and increase in the likelihood of nursing home move, but stroke did not accelerate subsequent disability accrual. Because of the high background rate of disability, stroke was not the dominant determinant of population-level disability in older adults with AF.

Introduction

Atrial fibrillation (AF) is a significant health burden for older adults, affecting 1 in 25 of those aged over 60 and 1 in 10 aged over 80.[1] The prevalence of AF is projected to increase alongside the aging of the U.S. population. By 2030, an estimated 12 million adults will have AF, and more than half of these patients will be aged over 80.[2]

Stroke is the most dreaded consequence of AF for older adults, who often equate stroke with abrupt and persistent loss of independence. Prior studies have clearly demonstrated that compared with strokes occurring in people without AF, AF-related strokes result in worse acute neurologic impairments and increased short-term disability.[3,4] Yet long-term functional outcomes for AF patients generally, and specifically before and after stroke, remain uncharted. While many strokes result in sudden and life-altering disability, disability can also result from an accumulation of impairments independent of stroke. Particularly in older adults, AF frequently coexists with other medical conditions that increase the risk of disability.[5,6] Also, while often overlooked, geriatric syndromes, such as falls and cognitive impairment, are important contributors to loss of independence in older AF patients.[7,8] In large and nationally representative cohorts of older adults with AF, frailty, cognitive impairment, and functional impairments are common.[9,10] In the absence of longitudinal data in older adults with AF, the contribution of stroke and factors besides stroke to long-term disablement remain unclear.

Stroke is perceived as a dominant pathway to disability in patients with AF, yet information assessing its actual population health burden is limited. Compared to the prevalence of other risk factors for disability, stroke remains an uncommon occurrence even among AF patients. Thus, many older adults with AF may be predisposed to disablement even in the absence of stroke, but this has not been previously quantified.

Understanding the longitudinal course of independence of older patients with AF, and whether and to what degree stroke affects their long-term trajectory, is vital to inform treatment decision-making, advance care planning, and public health interventions. To address these gaps, we used a nationally representative cohort of older adults with incident AF to determine long-term functional outcomes and the relative contribution of strokes.

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