Evidence-based therapies for myocardial infarction: secular trends and determinants of practice in the community.

OBJECTIVES: To examine secular trends in the use of evidence-based therapies in a geographically defined cohort of patients with myocardial infarction (MI) and to test the hypotheses that baseline use is increasing and that disparities in use are diminishing, PATIENTS AND METHODS: All consecutively hospitalized patients who were dismissed from Olmsted County, Minnesota, hospitals between 1979 and 1998 with a diagnosis of MI were identified using standardized criteria (biomarkers, cardiac pain, and electrocardiography). The entire community medical record, available via the Rochester Epidemiology Project, was reviewed to ascertain baseline characteristics including comorbidity, presence of ST-segment elevation on electrocardiography, and treatment. Logistic regression models were used to examine the association of treatment with age and sex, independent of other baseline characteristics.
RESULTS: Between 1979 and 1998, 2317 incident MIs (patient mean +/- SD age, 67+/-14 years; 43% women; 57% aged > or = 65 years) occurred in Olmsted County. The use of all evidence-based therapies increased over time, primarily reflecting the introduction of these medications at the time of Index MI. Between 1989 and 1998, age was not independently associated with use of aspirin or ACE inhibitors. Disparities in use persisted for reperfusion therapy and beta-blockers. Reperfusion therapy or revascularization was used less frequently in older persons, particularly in elderly women (P<.001). Use of beta-blockers decreased 16% among persons aged 65 years or older, independent of measurable differences in baseline characteristics and MI severity (hazard ratio, 0.84; 95% confidence interval, 0.74-0.93).
CONCLUSIONS: The use of all evidence-based therapies for MI increased markedly over time; however, residual gaps in use were noted. Reperfusion therapy or revascularization is used less frequently in women and elderly persons, and beta-blockers are used less frequently in elderly persons. These differences are not explained by measurable differences in baseline characteristics. Women and elderly persons represent an increasing proportion of patients with MIs in the community; therefore, these findings define therapeutic opportunities.