Relative Contribution of Trends in Myocardial Infarction Event Rates and Case Fatality to Declines in Mortality: An International Comparative Study of 1.95 Million Events in 80.4 Million People in Four Countries

Background: Myocardial infarction (MI) mortality has declined since the 1970s, but contemporary drivers of this trend remain unexplained. The aim was to compare contribution trends in event rates and case fatality declines MI four high-income jurisdictions from 2002-2015. Methods: Linked hospitalisation data were obtained New South Wales (NSW), Ontario, Zealand England. Age-adjusted estimated Poisson binomial regression models, their relative calculated.     Findings: A total 1,947,895 events identified ≥30 year olds. There significant mortality, all jurisdictions. Age-standardised highest (men: 893/100,000 2002, 536/100,000 2015; women: 482/100,000 271/100,000 2015) lowest England 513/100,000 382/100,000 238/100,000 173/100,000 2015). Annual age-adjusted reductions ranged -2·6% (95% CI -2·7, -2·6) men -4·3% -4·4, -4·1) women Ontario. 2002 (48%) at a greater rate than other -4·1%/year, CI: -4·2, -4·0%); -4·4%/year, -4·5, -4·3%)). Declines -6.1%/year -7.6%/year. Event contributor Ontario (69·4%), (men 68·4%; 67·5%) NSW (60·1%), while (60% women). contributions younger age groups older groups. Interpretation: varied between jurisdictions, including by sex. Understanding causes variation will enable optimisation prevention treatment efforts.   Funding Information: NHMRC (Australia); Health Research Council Zealand; Canadian Institutes for Research; National Institute Research, Oxford. Declaration Interests: None declare. Ethics Approval Statement: This study approved University Toronto Sciences Ethics Board, Population & Services Committee (reference 2016/09/654), Disability Committees number H13/049) Central Bristol Multi-Centre (04/Q2006/176).