Trends in survival after myocardial infarction in New Zealand, 1974-81.

Coronary heart disease mortality in New Zealand has declined by 20% in the 13 years since 1968. One possible explanation for this decline is lower case-fatality rates resulting from improvements in the management of myocardial infarction. This paper tests this hypothesis by examining trends in 1-year survival following a definite myocardial infarction for the population aged 35-69 in Auckland. The data were obtained from two methodologically identical population-based registers of myocardial infarction compiled in 1974 and 1981 in Auckland. In both periods the 1-year crude case-fatality rate was 30% and the pattern of survival over 1 year was similar. These data suggest that factors other than the improved care of myocardial infarction patients are responsible for the decline in coronary heart disease mortality rates in New Zealand.