Trends in 28 day and one year survival in patients hospitalized for an incident acute myocardial infarction in Norway during 2001-2009; a CVDNOR project

Purpose: Acute myocardial infarction (AMI) is the major contributor of cardiovascular (CVD) mortality. Improved survival is a potential cause of the decline in AMI mortality. The purpose was to explore trends in survival after an incident AMI in Norway during 2001-2009. Methods: "Cardiovascular disease in Norway" (CVDNOR) is a research project including hospitalizations with a CVD diagnosis during 1994-2009 in Norway. Hospitalizations for incident AMIs (defined as absence of previous AMI hospitalizations during the past 7 years) were extracted. Information on date and cause of death was obtained from the Cause of Death Register. Kaplan–Meier curves were constructed for all cause and CVD mortality according to three time periods and P values from log rank tests for trend are given (Figure). The relationship between year of AMI and survival was explored by Cox proportional hazards regression. Hazard ratios (HR) with 95% confidence intervals (CI) were calculated for one year change (trend analysis) adjusted for sex, age, education level and marital status. Results: During 2001-2009, 110 729 incident AMI hospitalizations (38.8% women) were identified. Mean age (SD) was 72.3 (13.7) years. 17 792 (16.2%) patients died within 28 days. 13 930 were CVD deaths. 30 009 (27.1%) patients died within the first year. 21 019 were CVD deaths. Overall, 28-day mortality decreased by 31% (HR=0.69; 95% CI 0.65-0.73) for all cause and by 44% (HR=0.56; 95% CI 0.53-0.59) for CVD mortality. One-year mortality decreased by 24% (HR=0.76; 95% CI 0.72-0.78) for all cause and by 35% (HR=0.65; 95% CI 0.62-0.68) for CVD mortality. 28 days and one year survival after AMI Conclusions: During 2001-2009, 28-day and one-year mortality after an incident AMI declined substantially in Norway. CVD mortality (28-day and one-year) declined more than all-cause mortality.