Functional disability before myocardial infarction in the elderly as a determinant of infarction severity and postinfarction mortality.

BACKGROUND: Functional disability is a common condition among elderly patients. However, to our knowledge, its effect on outcome of myocardial infarction (MI) has not been assessed. Our objectives were to determine whether disability in the activities of daily living measured before MI is a predictor of MI severity and mortality.
METHODS: Disability in activities of daily living was measured prospectively in a cohort of 222 patients who were hospitalized with acute MI. Outcome measures were severity characteristics on admission to the hospital (higher Killip class, presence of new Q waves in the first electrocardiogram, and lower systolic blood pressure), and 6-month mortality.
RESULTS: Patients with disability before hospitalization were older and had more comorbidity. After adjusting for these factors and for delay in hospital arrival, disability was still significantly associated with clinical severity on admission to the hospital and with mortality (adjusted relative risk of death for patients with disability vs patients without disability, 2.01; 95% confidence interval, 1.23-3.28). Clinical severity and hospital treatment explained the higher mortality of patients with disability. When these factors were added to the previous model, the relative risk of mortality for patients with disability vs patients without disability was 1.24, and the 95% confidence interval was 0.73 to 2.12.
CONCLUSIONS: Functional disability in activities of daily living before MI is an important predictor of clinical severity and mortality in elderly patients with MI. This effect is only minimally explained by the older age and higher comorbidity of patients with disability. However, higher clinical severity and lower use of treatment interventions are major determinants of their higher mortality compared with patients without disability.