Disability Trajectories Before and After Stroke and Myocardial Infarction: The Cardiovascular Health Study

Abstract

Importance: Ischemic strokes may accelerate long-term functional decline apart from their acute effects on neurologic function.

Objective: To test whether the increase in long-term disability is steeper after than before the event for ischemic stroke but not myocardial infarction (MI).

Design, settings, and participants: In the population-based, prospective cohort Cardiovascular Health Study (1989-2013), longitudinal follow-up was conducted for a mean (SD) of 13 (6.2) years. Follow-up data were used until September 1, 2013; data analysis was performed from August 1, 2013, to June 1, 2016. Models based on generalized estimating equations adjusted for baseline covariates and included a test for different slopes of disability before and after the event. Participants included 5888 Medicare-eligible individuals 65 years or older who were not institutionalized, expected to reside in the area for 3 or more years, and able to provide informed consent. Exclusions were needing a wheelchair, receiving hospice care, and undergoing radiotherapy or chemotherapy.

Exposures: Ischemic stroke and MI.

Main outcomes and measures: Annual assessments with a disability scale (measuring activities of daily living [ADLs] and instrumental ADLs). The number of ADLs and instrumental ADLs (range, 0-12) that the participant could not perform was analyzed continuously.

Results: The mean (SD) age of the entire cohort (n = 5888) was 72.8 (5.6) years; 2495 (42.4%) were male. During follow-up, 382 (6.5%) participants had ischemic stroke and 395 (6.7%) had MI with 1 or more disability assessment after the event. There was a mean of 3.7 (2.4) visits before stroke and 3.7 (2.3) visits after stroke; there was a mean of 3.8 (2.5) visits before MI and 3.8 (2.4) visits after MI. The increase in disability near the time of the event was greater for stroke (0.88 points on the disability scale; 95% CI, 0.57 to 1.20; P < .001) than MI (0.20 points on the disability scale; 95% CI, 0.06 to 0.35; P = .006). The annual increase in disability before stroke (0.06 points per year; 95% CI, 0.002 to 0.12; P = .04) more than tripled after stroke (0.15 additional points per year; 95% CI, 0.004 to 0.30; P = .04). The annual increase in disability before MI (0.04 points per year; 95% CI, 0.004 to 0.08; P = .03) did not change significantly after MI (0.02 additional points per year; 95% CI, -0.07 to 0.11; P = .69).

Conclusions and relevance: In this large, population-based study, a trajectory of increasing disability became significantly steeper after stroke but not after MI. Thus, in addition to the acute brain injury and consequent impairment, ischemic stroke may also be associated with potentially treatable long-term adverse effects on the brain that lead to accelerated functional decline.

Figure 1. Conceptual Depiction of Concepts Examined

A) The trajectory of disability in relation to stroke B) Estimated parameters

Figure 1. Conceptual Depiction of Concepts Examined

A) The trajectory of disability in relation to stroke B) Estimated parameters