The Disability Burden Associated With Stroke Emerges Before Stroke Onset and Differentially Affects Blacks: Results From the Health and Retirement Study Cohort

Independence in instrumental activities of daily living (IADLs) is an essential component of health in middle and older age. People with more independence in carrying out IADLs—tasks like managing money, grocery shopping, using a map, talking on the telephone, preparing meals, and managing medications—have better self-reported subjective health measures including quality of life and self-rated health (1–3) as well as more objective health outcomes like lower mortality risk (4–6). IADL dependence also imposes a substantial burden on caregivers and health service providers: individuals with IADL dependence often require help from others (7) and those with IADL limitations incur roughly $2,000 more annually to Medicare Part A compared with individuals with no disability (8). Although IADL independence typically declines with age (9), such declines may be accelerated by onset of acute medical events such as stroke (10,11). Studies of rehabilitation and health poststroke very commonly use IADLs as an outcome measure since strokes may affect one’s ability to carry out physically and cognitively demanding tasks like IADLs (11–13). However, studies that only consider IADLs poststroke, without describing the trajectory of IADL changes prior to stroke, may be inadequate to describe the effect of stroke onset on a person’s IADLs. Several studies have found pre-event disability associated with onset and mortality from acute health events, such as myocardial infarction (14,15) or stroke (16–20). However, these prior studies have looked only at basic activities of daily living. To our knowledge, no study has prospectively described changes in IADL independence prior to and following stroke onset. Such evidence is essential to understand how the consequences of stroke differ by patient characteristics such as sex, race, or geographic area of residence. Although there are noted differences in stroke outcomes by demographic characteristics (21–26), it is yet unknown if these differences merely reflect patterns that prevailed prior to stroke or result from differences in the consequences of stroke per se. We used data from the U.S. Health and Retirement Study (HRS), a nationally representative sample of adults aged 50+, to assess trends in independence in six IADLs by stroke status over 12 years of follow-up. We compared IADL trends between respondents who did not have a stroke during follow-up to those who reported a stroke during follow-up. We also described IADL trends among those who had a stroke by their mortality status poststroke. We hypothesized that (i) even before stroke, declines in IADL independence accelerate as the date of stroke approaches; (ii) among stroke survivors, independence is lower after stroke compared with before the stroke; (iii) among stroke survivors, IADL independence continues to decline during the years after stroke; and (iv) the effects of stroke on IADL disability will be larger for individuals at higher risk of stroke onset (men compared with women; blacks compared with whites; those born in the South compared with non-Southerners).