The effect of comorbidity on use of thrombolysis or aspirin in patients with acute myocardial infarction eligible for treatment.

Objective: Growing evidence indicates that life-sustaining therapies for the treatment of acute myocardial infarction (AMI) are underused among patients eligible for therapy, including the elderly and women. We examined the effect of a patient's comorbidity burden on use of these highly effective therapies in eligible populations of individuals with AMI.

Design: Retrospective cohort design.

Setting And Patients: We reviewed the medical records of 2,409 individuals at 37 Minnesota hospitals from October 1992 through July 1993 with an admission diagnosis of AMI, suspected AMI, or rule-out AMI, who met electrocardiographic, laboratory, and clinical criteria for AMI.

Measurements And Main Results: Using multivariate logistic regression models, we determined the association between a validated comorbidity measure and the proportion of eligible patients who received thrombolysis or aspirin. Controlling for other factors previously reported to influence rates of study treatment, the odds of receipt of thrombolysis among patients with severe comorbidity was 0.49 (95% confidence interval [CI] 0.27, 0.88) when compared with individuals without such limitation. Similarly, the odds of aspirin treatment among study patients with severe comorbidity was 0.46 (95% CI 0.30 0.72), compared with individuals without severe comorbidity. We did not distinguish any differences in patterns of treatment with either study treatment among patients with mild or moderate comorbidity when compared with individuals without any concomitant comorbidity.

Conclusions: This study indicates that patients with severe mental and physical comorbidities are less likely to receive standard therapies for AMI recommended in national treatment guidelines.