Estimation of the incidence of acute myocardial infarction using record linkage: a feasibility study in Nova Scotia and Saskatchewan. Nova Scotia-Saskatchewan Cardiovascular Disease Epidemiology Group.

The impact of cardiovascular disease prevention and therapeutic interventions may be reflected in the incidence and case-fatality of acute myocardial infarction. Relevant data can be obtained from carefully planned surveillance studies or from existing administrative data. Utilization of the latter is facilitated by record linkage of computerized provincial, regional and national databases. The validity of these data, particularly with respect to diagnostic codes, must be ensured. We estimated the incidence of fatal and non-fatal acute myocardial infarction (AMI) in Nova Scotia and Saskatchewan for 1977. Hospital discharge records from the two provinces for 1977 were linked with the Canadian Mortality Database (Statistics Canada) for residents of the two provinces. Whether an episode was a recurrent or initial one, was determined by a retrospective search through 1974. A random sample of hospital charts was examined for diagnostic validity. A higher incidence of acute myocardial infarction was found in Nova Scotia than in Saskatchewan. The proportion of fatal episodes was higher in Nova Scotia with the greatest difference in mortality occurring in deaths before formal hospitalization. Evaluation of cardiovascular health in the community, including an assessment of time trends as well as regional and provincial differences, is possible using routinely collected administrative data.