COMPARISON OF MORTALITY FROM ACUTE MYOCARDIAL-INFARCTION BETWEEN 1979AND 1992 IN A GEOGRAPHICALLY DEFINED STABLE-POPULATION

This study documents mortality from acute myocardial infarction (AMI), in hospital and at 1 year, for each of 3 selected 1-year periods in a stable community over a 13-year period beginning in 1979 and continui ng into the thrombolytic era, to detect any changes occurring in conju nction with the introduction of new therapies. Every patient with AMI occurring in a geographically defined stable community (Hamilton, Onta rio, Canada) in 3 1-year periods (1979 to 1980 [n=816], 1986 to 1987 [ n=816], and 1991 to 1992 [n=831]) was identified and clinically charac terized by standardized criteria. Subsequent in-hospital and 1-year su rvival were ascertained prospectively. The 3 cohorts were similar in p rognostic factors. Mean age was progressively greater over the study p eriod from 63 years in 1979 to 1980, to 67 years in 1991 to 1992 (p=0. 02). There was no change in in-hospital mortality rates from 1979 to 1 980 (17%) and 1986 to 1987 (16%). However, from 1986 to 1987 and 1991 to 1992, in-hospital mortality decreased from 16% to 9% (p <0.001) and 1-year mortality decreased from 26% to 19% (p <0.001). For patients w ho survived the hospital phase of AMI, 1-year mortality did not change and was between 11% and 12% in each of the 3 study periods. From 1986 to 1987 and 1991 to 1992, there was an increase in the use of thrombo lytic therapy from 5% to 44% of patients. The acute use of aspirin inc reased from 30% to 88% and the acute use of beta blockers increased fr om 19% to 48% of patients. The observed increase in use of these agent s could account for half of the actual mortality reduction observed. T his prospective population-based survey demonstrates improved in-hospi tal survival after AMI associated with increased use of established ef fective therapies between 1987 and 1992. The 1-year mortality of hospi tal survivors of AMI was unchanged throughout the period of study, rem aining at 11% to 12%. (C) 1996 by Excerpta Medica, Inc.