Body Mass Index and Mortality in Acute Myocardial Infarction Patients

The prevalence of obesity in the US has increased substantially in the past few decades. Current estimates place two thirds of adults in the US in the category of overweight or obese as defined by body mass index (BMI). In the general population, obesity is associated with numerous comorbidities and an increased risk of adverse outcomes, including cardiovascular disease and mortality. Among patients with chronic disease however, this association may be reversed. Evidence from observational studies of patients with heart failure suggests that obese patients may have improved short- and long-term prognoses.

This phenomenon, known as the “obesity paradox,” has been replicated in several settings that have shown either an inverse linear or U-shaped association between BMI and all-cause mortality in heart failure patients. Although the nature of this relationship is unclear, several explanations have been proposed, including residual confounding by patient and clinical characteristics. Relatively few studies have explored this relationship in patients with acute coronary syndrome or examined interactions between BMI and other demographic or health-related variables. Moreover, no studies of patients with acute coronary syndromes have examined BMI as a continuous variable to more fully characterize the actual shape of the mortality curve.

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–Emily M. Bucholz, MPH, Saif S. Rathore, MPH, Kimberly J. Reid, MS, Philip G. Jones, MS, Paul S. Chan, MD, Michael W. Rich, MD, John A. Spertus, MD, MPH, Harlan M. Krumholz, MD, SM

–This article originally appeared in the August 2012 issue of The American Journal of Medicine.