Educational attainment and differences in relative survival after acute myocardial infarction in Norway: a registry-based population study

Abstract

Background: Although there is a broad societal interest in socioeconomic differences in survival after an acute myocardial infarction, only a few studies have investigated how such differences relate to the survival in general population groups. We aimed to investigate education-specific survival after acute myocardial infarction and to compare this with the survival of corresponding groups in the general population.

Methods: Our study included the entire population of Norwegian patients admitted to hospitals for acute myocardial infarction during 2008-2010, with a 6- year follow-up period. Patient survival was measured relative to the expected survival in the general population for three educational groups: primary, secondary and tertiary. Education, sex, age and calendar year-specific expected survival were obtained from population life tables and adjusted for the presence of infarction-related mortality.

Results: Six-year patient survivals were 56.3% (55.3-57.2) and 65.5% (65.6-69.3) for the primary and tertiary educational groups (95% CIs), respectively. Also 6-year relative survival was markedly lower for the primary educational group: 70.2% (68.6-71.8) versus 81.2% (77.4-84.4). Throughout the follow-up period, patient survival tended to remain lower than the survival in the general population with the same educational background.

Conclusion: Both patient survival and relative survival after acute myocardial infarction are positively associated with educational level. Our findings may suggest that secondary prevention has been more effective for the highly educated.

Keywords: coronary heart disease; education; health inequalities; mortality; record linkage.

Figure 1

Patient survival and expected survival, according to years since diagnosis and educational group. The upper, nearly linear curves show expected survival rates, as calculated using the Ederer I method. The lower curves show patient survival rates, as estimated using the Kaplan-Meier method. Results are standardised for age and sex.