Study on correlation of obesity with short-term prognosis in acute myocardial infarction.

Background: Obese patients with established coronary artery disease have reduced mortality compared to normal or low body mass index (BMI) patients. The reason for the relation is not yet clearly understood. We sought to evaluate the association of BMI and waist circumference (WC) at the time of presentation in patients with myocardial infarction (MI) with one-year adverse cardiac events.

Methods: In this prospective cohort study, we included consecutive patients with acute MI admitted to a tertiary care hospital during a period of one year. Upon admission, BMI and WC were measured. Patients were followed-up for a period of one year and the primary composite outcome of death or non-fatal MI was correlated with BMI and WC categories.

Results: There were 703 patients (males 559 (79.5%)). Combined non-fatal MI and death at one year was 128 (18.2%). Incidence of primary outcome was 25.0% in low BMI group, 19.9% in normal BMI group, 13.1% in overweight group, 13.4% in class I obese, and 11.1% in class II obese groups. In univariate analysis, the inverse correlation was significant (p value=0.007). In one-year follow-up period, 12.8% in high and 20.8% in normal WC groups had primary outcome (p value=0.01). Both BMI and WC lost their predictive value in multivariate analysis.

Conclusions: Low BMI and normal WC were associated with a worse short-term outcome in patients with acute MI. Neither BMI nor WC independently predicted cardiac events or death after acute MI.