Relation between body mass index and clinical outcome in acute myocardial infarction

Obesity has long been identified as a risk factor for coronary artery disease. However, the data evaluating outcomes in patients with acute myocardial infarction (AMI) related to body mass index (BMI) are limited and inconsistent. Patients (n = 284) who were diagnosed with AMI at the Medical College of Georgia from January 1, 2003 to June 25, 2004, were included in this retrospective analysis. BMI, risk for factors for coronary artery disease, AMI characteristics, and outcome variables were obtained from chart records. Logistic and multiple regression techniques were used to model and test hypotheses regarding the effect on outcomes after AMI, adjusting for cardiac risk factors, demographics, and other contextual variables. Compared with normal weight patients, underweight patients had more (65% vs 40%) and morbidly obese patients had fewer (21% vs 40%) ST-elevation AMIs (p = 0.014). Among all patients with AMIs, morbidly obese patients tended to be younger than normal weight subjects. No adverse relations among BMI and mortality, length of stay, readmission rates, or revascularzation in AMI were identified in this analysis. Both diabetes and previous aspirin use were found to increase the odds of in-hosptial mortality during AMI independent of BMI. In conclusion, despite the association between obesity and development of coronary artery disease, obesity does not adversely impact in-hospital outcomes in AMI. However, obesity is associated with AMI at a younger age.