Trends in Incidence of Hospitalized Acute Myocardial Infarction in the Cardiovascular Research Network (CVRN).

BACKGROUND

Monitoring trends in cardiovascular events can provide key insights into the effectiveness of prevention efforts. Leveraging data from electronic health records provides a unique opportunity to examine contemporary, community-based trends in acute myocardial infarction hospitalizations.

METHODS

We examined trends in hospitalized acute myocardial infarction incidence among adults aged ≥25 years in 13 US health plans in the Cardiovascular Research Network. The first hospitalization per member for acute myocardial infarction overall and for ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction was identified by International Classification of Diseases, Ninth Revision, Clinical Modification primary discharge codes in each calendar year from 2000 through 2008. Age- and sex-adjusted incidence was calculated per 100,000 person-years using direct adjustment with 2000 US census data.

RESULTS

Between 2000 and 2008, we identified 125,435 acute myocardial infarction hospitalizations. Age- and sex-adjusted incidence rates (per 100,000 person-years) of acute myocardial infarction decreased an average 3.8%/y from 230.5 in 2000 to 168.6 in 2008. Incidence of ST-segment elevation myocardial infarction decreased 8.7%/y from 104.3 in 2000 to 51.7 in 2008, whereas incidence of non-ST-segment elevation myocardial infarction increased from 126.1 to 129.4 between 2000 and 2004 and then decreased thereafter to 116.8 in 2008. Age- and sex-specific incidence rates generally reflected similar patterns, with relatively larger decreases in ST-segment elevation myocardial infarction rates in women compared with men. As compared with 2000, the age-adjusted incidence of ST-segment elevation myocardial infarction in 2008 was 48% lower among men and 61% lower among women.

CONCLUSIONS AND RELEVANCE

Among a large, diverse, multicenter community-based insured population, there were significant decreases in incidence of hospitalized acute myocardial infarction and the more serious ST-segment elevation myocardial infarctions between 2000 and 2008. Decreases in ST-segment elevation myocardial infarctions were most pronounced among women. While ecologic in nature, these secular decreases likely reflect, at least in part, results of improvement in primary prevention efforts.