Obesity and heart failure prognosis: paradox or reverse epidemiology?

Abstract

This editorial refers to ‘Effect of obesity and being overweight on long-term mortality in congestive heart failure: influence of left ventricular systolic function’† by F. Gustafsson et al. , on page 58 Obesity is a problem reaching epidemic proportions in westernized society and is a major cause of preventable death.1 Obesity has many adverse effects on coronary artery disease (CAD) risk factors and is probably an independent risk factor for CAD events. Epidemiological studies have clearly shown a strong relationship between obesity and increased risk of cardiovascular disease and mortality in the general population,1,2 although in some of these studies a ‘J-shaped’ or ‘U-shaped’ curve has been present, meaning that those individuals with low body mass index (BMI) also have increased mortality. Obesity is also known to exert numerous adverse effects on cardiac function. In early obesity, an expanded intravascular volume results in an increase in cardiopulmonary volume or increased pre-load.1,3 Over time these changes lead to an increased prevalence of eccentric left ventricular hypertrophy and the propensity for more complex ventricular dysrhythmias; we and others have noted these early abnormalities as well as improvements in both diastolic and systolic ventricular function following marked, purposeful weight reduction.1 Finding the relationship between obesity and heart failure (HF), however, has been complex. A recent epidemiological study from the Framingham Heart Study clearly indicates that obesity and being overweight are potent predictors of subsequent clinical HF.4 Although obesity causes abnormalities in diastolic and systolic function and predisposes to clinical HF, obese patients with … *Corresponding author. Tel: +1 504 842 5874; fax: +1 504 842 5875. E-mail address : clavie{at}ochsner.org