Obese heart failure patients outlive leaner cohorts in population study

Continuing the debate over the so-called “obesity paradox,” more obese and overweight patients may develop heart failure, but fewer die from it than lean counterparts, according to a study published in the Dec. 30 issue of the Journal of the American College of Cardiology.

Using patients enrolled in the ongoing Atherosclerosis Risk in Communities study, Umair Khalid, MD, of Baylor College of Medicine in Houston, and colleagues looked at trajectories through 10 years for incident heart failure. The study used body mass index (BMI) measurements to determine normal, overweight and obese cohorts.

Overweight patients comprised 35 percent of those who developed heart failure and 47 percent were obese. Over the 10-year span, 43 percent of patients with heart failure died. While more patients who were overweight or obese developed heart failure, fewer died across the monitored span. Both overweight and obese patients had one third less risk of death, as observed during the study (hazard ratio 0.72 and 0.7 respectively.) These findings appeared consistent regardless of history of smoking, cancer or diabetes.

However, Khalid et al were unable to speak directly to what may be driving the perceived paradox. They noted previously proposed mechanisms, including higher metabolic reserves against cachexia, neurohormonal pathways and comorbid confounders.

Over time, however, the findings seemed to indicate whatever protective mechanisms exist may deteriorate and ultimately survival declines were seen in later years.

Thomas J. Wang, MD, of the Vanderbilt University Medical Center in Nashville, Tenn., noted in an editorial that while the findings of this study add considerably to the obesity paradox question, further studies were needed to confirm what Khalid et al found. In particular, studies needed to identify drivers for the perceived paradox.

“Ultimately, a better mechanistic understanding of what drives the obesity paradox should serve as the basis for postulating whether an 'optimal' BMI exists for heart failure patients and whether interventions are warranted to maintain or achieve this BMI,” Wang wrote.