the obesity paradox observed in cardiology research

The Association Between Obesity and In-Hospital Mortality in Patients with Cardiogenic Shock Complicating Acute Myocardial Infarction

May 3, 2017

Key Takeaways

  • Obesity is paradoxically associated with favorable mortality outcomes in acute myocardial infarction (AMI).
  • Association between obesity and in-hospital mortality among patients with cardiogenic shock (CS) complicating AMI (N=290,894) was retrospectively studied.
  • Obese patients had lower in-hospital mortality compared with nonobese patients (28.2% vs 36.5%, respectively), but key baseline differences in the obese group may explain this association.

More than one-third of the adult population in the United States (35.7%) are considered clinically obese.1 The increasing prevalence of obesity has become difficult to ignore as research continues to support the association of obesity--defined as a body mass index of 30 or greater--with poor cardiovascular health.

Despite obesity having a direct link to known cardiovascular risk factors, including diabetes, hypertension, and hypercholesterolemia, previous research has shown a paradoxical protective association between obesity and established cardiovascular disease.2 This “obesity paradox” states that patients with obesity may have better outcomes following a cardiovascular event when compared with nonobese patients.

Chatterjee K et al retrospectively examined obese and nonobese patients from the National Inpatient Sample databases to determine the differences in regard to the incidence of in-hospital mortality associated with cardiogenic shock (CS) complicating acute myocardial infarction (AMI).3 A total of 290,894 patients in the database, of which 8.9% (n=25,835) were considered obese, were hospitalized with AMI complicated by CS.

As predicted, obese patients presented with a higher prevalence of risk factors associated with heart disease, including hypertension, diabetes, and dyslipidemia. Additionally, obese patients were more likely to have had a previous myocardial infarction and percutaneous coronary intervention (PCI) than nonobese patients.

Although obese patients had a significantly lower in-hospital mortality rate than nonobese patients (28.2% vs 36.5%, respectively), there were key differences related to baseline characteristics and treatment protocol that may explain this association. Obese patients, on average, with AMI in this sample were 6 years younger than nonobese patients and were more likely to receive either PCI, thrombolysis, or coronary artery bypass grafting (73.0% vs 63.4%).

Heart failure patients with concurrent obesity may possess greater protection against cachexia and inflammation due to these patients’ higher metabolic reserve.4 Previous research has shown that obese patients also have lower concentrations of interleukin-6 and monocyte chemoattractant protein-1, key inflammatory cytokines associated with the inflammation commonly seen in heart disease, and may therefore partly explain the “obesity paradox” observed in cardiology research.5,6,7

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  1. Ogden CL, Carroll MD, Fryar CD, Flegal KM. Prevalence of Obesity Among Adults and Youth: United States, 2011-2014. NCHS Data Brief. 2015;(219):1-8.
  2. Horwich TB, Fonarow GC, Hamilton MA, et al. The relationship between obesity and mortality in patients with heart failure. J Am Coll Cardiol. 2001;38(3):789-795.
  3. Chatterjee K, Gupta T, Goyal A, et al. Association of Obesity With In-Hospital Mortality of Cardiogenic Shock Complicating Acute Myocardial Infarction. Am J Cardiol. 2017.
  4. Horwich TB, Fonarow GC. Measures of obesity and outcomes after myocardial infarction. Circulation. 2008;118(5):469-471.
  5. Martí A, Marcos A, Martínez JA. Obesity and immune function relationships. Obes Rev. 2001;2(2):131-140.
  6. Danesh J, Kaptoge S, Mann AG, et al. Long-term interleukin-6 levels and subsequent risk of coronary heart disease: two new prospective studies and a systematic review. PLoS Med. 2008;5(4):e78.
  7. Deshmane SL, Kremlev S, Amini S, Sawaya BE. Monocyte chemoattractant protein-1 (MCP-1): an overview. J Interferon Cytokine Res. 2009;29(6):313-326.


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