Long-term individual and population functional outcomes in older adults with atrial fibrillation.

Background: Older adults with atrial fibrillation (AF) have multiple risk factors for disablement. Long-term function and the contribution of strokes to disability has not been previously characterized.

Methods: We performed a longitudinal, observational study in the nationally representative Health and Retirement Study (1992-2014). We included participants ≥65 years with Medicare claims who met incident AF diagnosis claims criteria. We examined the association of incident stroke with three functional outcomes: independence with activities of daily living (ADL) and instrumental activities of daily living (IADL) and community-dwelling. We fit separate logistic regression models with repeated measures adjusting for comorbidities and demographics to estimate the effect of stroke on function. We estimate the contribution of strokes to the overall population burden of functional impairment using the method of recycled predictions.

Results: Among 3530 participants (median age 79 years, 53% women, median CHA DS -VASc 5), 262 had a stroke over 17,396 person-years. Independent of stroke and accounting for population comorbidities, annually, ADL dependence increased by 4.4%, IADL dependence increased by 3.9%, and nursing home residence increased 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 7.4years.

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

Impact statement: We certify that this work is novel. Little is known about long-term function (ADL, IADL, community-dwelling) among older adults with AF and the association with stroke. This nationally representative study finds a high rate of function loss independent of stroke, and among those who suffer a stroke, a dramatic and immediate decline in function. Because of the high rate of function loss independent of stroke and the relatively low rate of stroke, on a population level, stroke is not the dominant determinant of disability in older adults with AF.