Incidence and case fatality after day 28 of first time myocardial infarction in Sweden 1987−2008

Abstract

Aims: We studied trends in first-time myocardial infarction (MI) incidence and case fatality after day 28 and to examine the role of sex, education as an indicator for socioeconomic position, and birth country on these events in Sweden.

Methods and results: Nationwide cohort including 6,752,655 individuals aged 35–89 years living in Sweden between January 1987 and December 2008, of which, 6,464,968 individuals and 366,085 nonfatal first-time MI patients were classified according to their sex, birth country, and education and followed over two decades. Main outcome measures: Incidence and case-fatality rate after day 28 of first-time MI and their trends. A decreasing trend for first-time MI incidence and case fatality after day 28 for both sexes regardless of birth country was observed (p-trend<0.0001). The trend was, however, less pronounced among female and foreign-born. Men had higher incidence than women (incidence rate ratio, IRR 2.09, 95% CI 2.08–2.11). Men born in Southern and Western Asia had 50% (95% CI 40−60%) higher risk than men born in Sweden. Incidence was 50–80% higher in the least educated irrespective of sex and birth country (p-trend<0.0001). This association was stronger for female and foreign-born. We observed a 15% higher case fatality after day 28 among men than women (hazard ratio, HR 1.15, 95% CI 1.13–1.17) and 20−40% lower case fatality after day 28 among patients with no diabetes. Low education was associated with 50% higher case fatality after day 28 regardless of sex and birth country (p-trend <0.0001).

Conclusion: Although incidence of, and fatality after, first-time MI continued to decrease, low socioeconomic position, independent of birth country and sex, remained an important risk indicator for both events.