Background: The objective of the study was to analyse the number of AMI (acute myocardial infarctions) registered in the period 1991 - 2007, with special emphasis on the development after 1999, and with this background discuss changes in incidence.
Material and methods: We analysed data from NPR (the Norwegian Patient Register), on patients discharged from hospitals in the period 1991 - 2007 with the main diagnosis AMI. For the year 2004, a patient-based dataset was made available from SINTEF Health Research/NPR. The time for when troponin assays (for diagnosing AMI) were implemented in Norwegian hospitals was recorded through a questionnaire survey.
Results: The number of discharges for these patients decreased during the 90 s. From 2000 to 2007, the total number of discharges increased considerably (from 11,892 to 19,757 [66 %]). In patients below 80 years of age the number of discharges per 100,000 inhabitants was 283 in 1991 and 196 in 1999. After controlling for patient transfers between hospitals and introduction of troponins for diagnosing of AMI, the number of patients below 80 years admitted to hospital in 2004 was estimated to 142 - 162 per 100,000 inhabitants.
Interpretation: The trend for a decrease in AMI incidence seems to have continued from the 1990 s to after 2000 for the age groups below 80.