Obesity

New Findings Contradict the Obesity Paradox in Acute Coronary Syndromes

Although obesity is believed to have protective effects on mortality among patients with acute coronary syndromes (ACS), findings of a new study conflict this obesity paradox.

To conduct the study, the researchers assigned 1209 participants in the START-ANTIPLATELET registry to 1 of 3 groups, according to their body mass index (BMI):

  • 410 participants were assigned to the normal weight group (BMI of less than 25 kg/m2)
  • 538 participants were assigned to the overweight group (BMI of 25 kg/m2 to 29.9 kg/m2)
  • 261 participants were assigned to the obese group (BMI of 30 kg/m2 or more)

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The researchers assessed for net adverse clinical endpoints (NACE), which was defined as a composite of all-cause death, myocardial infarction (MI), stroke, and major bleeding. 

Compared with participants who were normal weight, participants who were obese or overweight had:

  • A higher prevalence of cardiovascular risk factors 
  • A better left ventricular ejection fraction 
  • A lower PRECISE-dual antiplatelet therapy (PRECISE-DAPT) score

The participants who were overweight or obese were also younger.

At the 1-year follow-up, participants in the normal-weight group had a higher incidence of NACE (15.1%) than the participants in the overweight (8.6%) or obese (9.6%) groups. This difference was due in large part to a significantly higher rate of all-cause death in the normal weight group (6.3%) vs the overweight (2.6%) or obese (3.8%) groups.

There was no significant difference between the groups for MI, stroke, or major bleeding.

The researchers determined that because BMI loses its power in independently predicting outcomes after correction for confounding variables, the obesity paradox in a real-world ACS population was not confirmed. 

“In conclusion, our study conflicts the obesity paradox in [a] real-world ACS population and suggest[s] that the reduced rate of adverse events and mortality in obese patients may be explained by relevant differences in the clinical risk profile and medications rather than BMI per se,” the authors wrote.

—Colleen Murphy

Reference:

Calabrò P, Moscarella E, Gragnano F, et al. Effect of body mass index on ischemic and bleeding events in patients presenting with acute coronary syndromes (from the START-ANTIPLATELET Registry). Am J Cardiol. 2019;124(11):1662-1668. https://doi.org/10.1016/j.amjcard.2019.08.030.