TRENDS IN IN-HOSPITAL MORTALITY FOLLOWING ACUTE MYOCARDIAL-INFARCTION(AIM) IN VICTORIA, 1987-1994

Background: Death rates from coronary heart disease have exhibited rem arkable declines in most industrialised countries. Cardiovascular mort ality has been the subject of extensive research and we considered it important to analyse recent local population based data on hospital ou tcomes of acute myocardial infarction (AMI). Aims: To document the tre nds in in-hospital mortality from AMI in Victoria from 1987-1994. Meth ods: This was a retrospective analysis of data from the Victorian Inpa tient Minimum Database relating to all public acute care hospitals, Al l separations recording a principal diagnosis 410 (AMI) were selected. Changes in distribution of AMI separations, in-hospital mortality, an d changes in length of stay were examined. Results: The mean age of wo men admitted was 72 years compared with 64 years for men. Women compri sed around a third of the overall sample but the proportion varied fro m 13% in those under 50 years to 57% among those aged 80 years and ove r. A striking decline in mortality was observed throughout the eight y ear period. The relative age adjusted decline was 33.5% (40% in males and 26% in females) with rates remaining higher in women. This decline occurred despite the increasing representation of those aged over 80 years. There was a significant decline in the mean length of stay (1.8 days) over the eight year period but this is likely to have had only minimal impact on mortality rates. Conclusion: We have documented welc ome declines in in-hospital mortality from AMI that are not an artefac t of declining lengths of stay. Our observations parallel those in sim ilar overseas studies. Large changes in medical management have taken place from the mid 1980s and may be partly responsible, but a change i n disease process cannot be ruled out.