Abstract 9577: 25-year Trends In First-time Hospitalization For Acute Myocardial Infarction, Subsequent Short- And Long-term Mortality, And The Prognostic Impact Of Gender And Comorbidity: A Danish Nationwide Cohort Study
Background: A marked decrease in incidence of acute myocardial infarction and associated mortality has occurred since 1980. No studies have reported on 25-year trends in a nationwide unselected population. We examined 25-year trends in first-time hospitalization for acute myocardial infarction in Denmark, subsequent short- and long-term mortality, and the prognostic impact of gender and comorbidity.
Methods: We conducted this nationwide population-based cohort study using medical registries. We identified all 234,331 patients with a first-time hospitalization for myocardial infarction from 1984 through 2008. We calculated the standardized incidence rate of myocardial infarction and 30-day and 31-365-day mortality by gender. We defined no, low, moderate, and high comorbidity levels according to the Charlson Comorbidity Index. We used Cox regression to compute mortality rate ratios comparing comorbidity categories.
Results:The standardized incidence rate per 100,000 persons decreased in the 25-year period by 37% for women (from 209 to 131) and by 48% for men (from 410 to 213). The 30-day mortality declined from 31.4% in 1984-1988 to 14.8% in 2004-2008. The 31-365-day mortality declined from 15.6% in 1984-1988 to 11.1% in 2004-2008. After adjustment for age at time of myocardial infarction, men and women had the same one-year risk of dying. The mortality reduction was independent of comorbidity level. Comparing patients with high and with no comorbidity during 2004-2008, the mortality rate ratio, adjusted for age and gender, was 1.96 (95% confidence interval: 1.83 to 2.11) within 30 days and 3.89 (95% confidence interval: 3.58 to 4.24) between 31 and 365 days.
Conclusion: The rate of first-time hospitalization for myocardial infarction and subsequent short-term mortality both declined by nearly half between 1984 and 2008. The reduction in mortality occurred for all patients, independent of gender and comorbidity. However, comorbidity burden was a strong prognostic factor for short and long-term mortality, while gender was not.
- © 2011 by American Heart Association, Inc.