Changes in the treatment and outcomes of acute myocardial infarction in Quebec, 1988-1995

Background: Few studies have reported population-based information on the t reatment trends and outcomes of patients who have had an acute myocardial i nfarction (AMI). We therefore examined patterns of care and outcomes for AM I patients in Quebec, Canada, between 1988 and 1995. Methods: Longitudinal data files of hospital admissions in Quebec (Med-Echo database) and inpatient and outpatient services (Regie de I'Assurance Mala die du Quebec database) were used to construct cohorts of all AMI patients in the province between 1988 and 1995. Temporal trends in the use of cardia c procedures alter an AMI, discharge prescriptions and mortality rates were examined. Results: Between 1988 and 1995 the age- and sex-adjusted rates of AMI in th e Quebec population declined (148 per 100 000 in 1988 to 137 per 100 000 in 1995). The use of intensive cardiac procedures increased in the same perio d; the 1-year cumulative incidence rate of catheterization increased from 2 8% in 1988 to 31% in 1994, that of angioplasty rose from 8% to 15% and that of coronary artery bypass surgery from 6% to 8%. Prescriptions for ASA, be ta-blockers, lipid-lowering agents and angiotensin-converting enzyme inhibi tors increased, and prescriptions for nitrates and calcium antagonists decr eased. These temporal changes were paralleled by a decrease in mortality ra tes post-AMI. All-cause 1-year cumulative incidence mortality rates decreas ed from 23% in 1988 to 19% in 1994. Interpretation: The decrease in AMI-related mortality in Quebec between 198 8 and 1995 may be linked to changes in treatment strategies (i.e., increase d use of cardiac surgical procedures and medications shown to increase surv ival).