Objective: To compare trends in incidence and case fatality of acute myocardial infarction (AMI) in Nova Scotia and Saskatchewan, provinces with the highest and lowest rates, respectively.
Design: Provincial hospital separation files were linked with mortality files and searched to identify incident cases in 1977, 1981 and 1985. The diagnoses were validated on a random sample of hospital charts with discharge codes 410 and 411 to 414 of the International Classification of Diseases of the World Health Organization.
Results: In spite of persisting differences between Nova Scotia and Saskatchewan, standardized AMI mortality and incidence rates in males and females have decreased, although at a slower rate in Saskatchewan. In both provinces the greatest decrease has occurred in male deaths prior to any hospital admission--likely representing cases of sudden death. Excess mortality in Nova Scotia is due predominantly to out-of-hospital deaths. Case fatality rates have declined in both provinces. The proportion of definite and possible AMI was similar in Nova Scotia and Saskatchewan in 1977, but not thereafter.
Conclusions: Along with a decline in ischemic heart disease mortality, there appears to be a decline in AMI incidence in Nova Scotia. Parallel studies of risk factor changes, interventive care and access to care are required to explain the observed phenomena.