Changing patterns of medical treatment in acute myocardial infarction. Observations from the Perth MONICA Project 1984-1990

Abstract

Type of study: Descriptive study of trends in the drug therapy for acute myocardial infarction.

Setting: Population-based register of acute coronary events compiled for the years 1984 to 1990 in the course of the Perth MONICA project.

Cases: 5294 cases meeting clinical criteria for acute myocardial infarction.

Results: Striking changes were seen in the use of aspirin before admission to hospital (from 4% to 18%). During the stay in hospital the use of beta-blockers increased steadily from 52% to 76%, while the use of aspirin increased 3.5-fold from 25% to 88% and the use of streptokinase increased 13.5-fold from 2.4% to 32.4%. The proportion of patients prescribed beta-blockers on discharge from hospital increased from 46% to 65% and that for aspirin rose from 16% to 83%. There were also major relative increases in the use of lipid-lowering agents and declines in the use of antiarrhythmic drugs.

Conclusion: These trends in the pharmacological management of myocardial infarction mirror the emerging evidence from clinical trials, although the increases in the use of certain types of drugs antedated publication of the results of major randomised studies. The changes in therapy would partly explain observed improvements in case fatality and may have contributed to the decline in coronary mortality observed in the Perth community.