Impact of Comorbidities on In-Hospital Mortality From Acute Myocardial Infarction, 2003-2009

Introduction and objectives: Treatment of acute myocardial infarction has changed notably in recent years. The objective of this study was to analyze trends in in-hospital mortality during the period 2003-2009 and to examine how changes in comorbidity indices affected mortality prediction models for acute myocardial infarction using the minimum basic data set. Methods: During the study period, 5275 cases of acute myocardial infarction were admitted. Mortality rates were calculated by age and sex and Charlson and Elixhauser comorbidity index scores were obtained on admission for every patient. Trends were analyzed and their validity studied. Multivariate models predictive of mortality were derived and compared. Results: Mean age and comorbidities increased in all patients over the period 2003-2009. In spite of these trends, acute myocardial infarction mortality decreased. Comorbidity indices remained valid when the criterion "present on admission" was applied. Multivariate predictive models included age, sex, medical treatment, coronary revascularization and a comorbidity index or specific comorbidities. The model with specific comorbidities showed the best predictive ability. All models found that age and comorbidities increased the risk of death, and that coronary revascularization and treatment with anticoagulants, fibrinolytics, and platelet antiaggregants were protective factors. Conclusions: Despite the fact that the mean age and number of comorbidities in acute myocardial infarction patients has increased year over year, acute myocardial infarction mortality has decreased, probably because of more frequent reperfusion and revascularization therapy and better medical treatment. (C) 2011 Sociedad Espanola de Cardiologia. Published by Elsevier Espana, S.L. All rights reserved.