Background: Disability in older adults is thought to occur primarily as a consequence of clinical disease episodes. However, the temporal relationship between clinical disease and disability has received little systematic attention.
Methods: Data from a prospective population-based study of 2812 older adults were analyzed to examine changes in disability before and after acute myocardial infarction. Disability outcomes included up to 9 yearly assessments of disability in activities in daily living, disability in basic physical functions, and disability in tasks requiring basic mobility and strength.
Results: A total of 279 myocardial infarctions occurred during 9 years of follow-up. After adjustment for age and sex, the average yearly increase in disability in activities of daily living and basic physical functions was not significantly greater in the 1-year period after myocardial infarction than in the 3-year period before myocardial infarction (P values >.20). Disability in basic mobility and strength showed a significantly greater increase in the year after myocardial infarction (P = .02). The results did not change after adjustment for comorbidity and chest pain or when restricted to incident cases of myocardial infarction or survivors. An additional exploratory analysis suggested that the rate of increase in some forms of disability may start to accelerate at about 1 year before the event, rather than after the event.
Conclusions: The increase in disability after myocardial infarction may form a continuation of increases that occur before the event and challenge commonly held notions about the temporal relationship between clinical disease and disability. Changes in disability before acute disease episodes may be related to subclinical disease.