Body mass index and the risk of recurrent coronary events following acute myocardial infarction

Although excess adiposity appears to increase the risk of coronary heart di sease in the general population, its importance in patients with establishe d coronary disease is less defined. We evaluated a population-based incepti on cohort of survivors to hospital: discharge following first acute myocard ial infarction (AMI) (n = 2,541) to assess the association between body mas s index (BMI) and the risk of recurrent coronary events and to explore the mechanisms for this relation. Using Cox proportional-hazards regression, we assessed the risk of recurrent coronary events associated with levels of a diposity as defined by BMI and then investigated potential mechanisms throu gh which adiposity conferred risk by examining how adjustment for diabetes mellitus, systemic hypertension, and dyslipidemia affected the association. Forty-one percent of the cohort were overweight (BMI 25 to 29.9), and 27.8 % were obese (BMI greater than or equal to 30). After adjustment for other risk factors, the risk of recurrent coronary events (n = 418) increased as BMI increased, especially among those who were obese. Using a BMI of 16 to 24.9 as the reference group, for mildly overweight patients (BMI 25 to 27.4 ), the relative risk (RR) was 0.93 (95% confidence interval [CII 0.70 to 1. 24); it was 1.16 for more severe overweight patients (BMI 27.5 to 29.9; 95% CI 0.87 to 1.55). For patients with class I obesity (BMI 30 to 34.9), the RR was 1.49 (95% CI 1.12 to 1.98), and for class II to III obesity (BMI gre ater than or equal to 35), the RR was 1.80 (95% Cl 1.30 to 2.48). We estima ted that clinical measurements of diabetes, hypertension, and dyslipidemia explained approximately 43% of this risk. Thus, excess adiposity as measure d by BMI was associated with an increased risk of recurrent coronary events following AMI, particularly among those who were obese. (C) 2001 by Excerp ta Medica, Inc.