Trends in incident acute myocardial infarction in Norway: An updated analysis to 2014 using national data from the CVDNOR project

Abstract

Background: We updated the information on trends of incident acute myocardial infarction in Norway, focusing on whether the observed trends during 2001–2009 continued throughout 2014. Methods: All incident (first) acute myocardial infarctions in Norwegian residents age 25 years and older were identified in the Cardiovascular Disease in Norway 1994–2014 project. We analysed overall and age group-specific (25–64 years, 65–84 years and 85 + years) trends by gender using Poisson regression analyses and report the average annual changes in rates with their 95% confidence intervals. Results: During 2001–2014, 221,684 incident acute myocardial infarctions (59.4% men) were identified. Hospitalised cases accounted for 79.9% of all incident acute myocardial infarctions. Overall, incident acute myocardial infarction rates declined on average 2.6% per year (incidence rate ratio 0.974, 95% confidence interval 0.972–0.977) in men and 2.8% per year (incidence rate ratio 0.972, 95% confidence interval 0.971–0.974) in women, contributed by declining rates of hospitalisations (1.8% and 1.9% per year in men and women, respectively) and deaths (6.0% and 5.8% per year in men and women, respectively). Declining rates were observed in all three age groups. The overall acute myocardial infarction incidence rates continued to decline from 2009 onwards, with a steeper decline compared to 2001–2009. During 2009–2014, gender-adjusted acute myocardial infarction incidence among adults age 25–44 years declined 5.3% per year, contributed mostly by declines in hospitalisation rates (5.1% per year). Conclusion: Acute myocardial infarction incidence rates continued to decline after 2009 in Norway in both men and women. The decline started to involve individuals aged 25–44 years, marking a turning point in the previously reported stagnation of rates during 2001–2009.