Trends in Acute Myocardial Infarction Event Rates and Risk of Recurrences After an Incident Event in Norway 1994 to 2009 (from a Cardiovascular Disease in Norway Project)

Abstract

We explored trends in acute myocardial infarction (AMI) event rates in Norway during 1994 to 2009 and trends in the 6-month, 1-year, and 3-year risk of recurrences after an incident AMI during 2001 to 2008 in men and women ≥25 years. Trends in AMI event rates (incident and recurrent) were analyzed using joinpoint regression analyses and expressed as annual percentage change (APC) in rates. Trends in AMI recurrences were explored using conditional risk models for ordered events in Cox regression. Analyses were stratified by gender and age group. Overall, AMI rates were stable during 1994 to 2002 but declined during 2002 to 2009 (APC = -2.0; 95% confidence interval [CI] -3.1 to -0.9 in men; APC = -2.1; 95% CI -3.8 to -0.5 in women). In the younger age group, rates declined during the whole study period in men (APC = -0.6; 95% CI -1.0 to -0.3) but not in women. Among older patients, no changes were observed during 1994 to 2002, whereas rates declined during 2002 to 2009 (APC = -2.6; 95% CI -3.8 to -1.4 in men; APC = -2.4; 95% CI -4.0 to -0.7 in women). During 2001 to 2008, in the older age group, the 6-month, 1-year, and 3-year risks of recurrences were reduced annually by 4.7%, 4.3%, and 5.4% in men and 5.2%, 5.0%, and 5.7% in women (all ptrend <0.001), respectively. No changes were observed in the younger age group. In conclusion, favorable trends in AMI event rates and recurrences observed in Norway were mostly seen among patients aged 65+ years, whereas less favorable trends were observed among younger patients, especially among women.