Background: This study compares in-hospital and 1-year mortality rates in two large cohorts of patients with acute myocardial infarction (AMI) who were admitted to coronary care units in Israel in 1981-1983 and in 1992. Since the late 1960s and early 1970s there has been a remarkable decline in mortality from cardiovascular causes in most Western countries; the reason for this decline is not completely understood. Although several studies have shown a significant decrease in in-hospital mortality from AMI between the 1960s and the 1980s, studies comparing survival after AMI between the 1980s and 1990s are relatively scarce. Over the past decade important medical treatments and procedures for the management of AMI were introduced.
Methods: Between August 1981 and July 1983, 5839 consecutive patients were admitted to 13 coronary care units in Israel with a confirmed diagnosis of AMI. Demographic and medical data from hospital charts were recorded. Mortality follow-up was complete for 99% of hospital survivors for a mean period of 10 years. A second cohort of 623 consecutive patients with AMI hospitalized during January and February of 1992 in the same 13 coronary care units were followed up for 1 year after discharge.
Results: Sex distribution and mean age were very similar in the two cohorts. Unadjusted in-hospital mortality was 18% in 1981-1983 versus 11% in 1992 (P < 0.001). After multiple regression analysis, the in-hospital mortality odds (adjusted for age, sex and history of previous infarction) declined from 1981-1983 to 1992 by 22-67%. The reduction in in-hospital mortality rates from 1981-1983 to 1992 was more pronounced among patients aged over 65 years. One-year survival was 91% and 92% in patients discharged in 1981-1983 and 1992, respectively; however, 1-year after discharge, the survival rate for patients older than 65 years was 85% in 1981-1983 versus 89% in 1992. None of the 5839 patients hospitalized in 1981-1983 received thrombolytic treatment or mechanical revascularization, whereas 46% and 9% of patients received these respective treatments in 1992.
Conclusions: This study suggests that, over the past decade, changes in medical treatment, thrombolytic therapy and mechanical revascularization have significantly contributed to the improvement of the immediate prognosis of patients hospitalized as a result of AMI.