'Obesity Paradox' in Myocardial Infarction Patients

Hahn, Sukwon

Abstract

BACKGROUND
Despite the adverse impact that being overweight or obese has on cardiovascular disorders, numerous studies have addressed the 'obesity paradox', which suggests that obese persons seem to have a better prognosis with these conditions than those with a normal body mass index (BMI). In addition, the effect of BMI on outcomes after percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) remains controversial.
METHODS
Our subjects included 457 patients who had undergone PCI for AMI between January 1, 2009 and September 30, 2011. They were classified into 3 groups according to baseline BMI - normal weight (BMI<23 kg/m2), overweight (BMI 23-25 kg/m2), obesity (BMI>25 kg/m2). Clinical characteristic and cardiovascular risk factors and major adverse cardiac events (MACE), including death after PCI, were compared among the groups.
RESULTS
Overweight or obese subjects were younger (P<0.001) and associated with higher left ventricle ejection fraction (LVEF) (P=0.012) and less frequency of MACE (P=0.003). Multiple logistic regression analysis showed that independent predictors for death and MACE were not obesity but age (P=0.006, P=0.017), high-density lipoprotein cholesterol (P=0.002, P=0.005) and LVEF (P=0.001, P<0.001).
CONCLUSIONS
In our study, BMI had no effect on MACE in patients undergoing primary PCI for AMI. The phenomenon, 'obesity paradox', may be explained by the possibility that AMI was diagnosed at a younger age in obese patients and that these younger patients had higher LVEFs than the other groups in this study.