Introduction: Obesity is strongly associated with increased cardiovascular diseases (CVD) and CV risk factors including diabetes mellitus, hypertension, and dyslipidemia. However, numerous studies have suggested an “obesity paradox”, where overweight and mild obese patients often have a better outcome than their leaner counterparts. Therefore, this study was aimed to characterize the association of BMI with inhospital and one year outcomes.
Methods: This hospital-based study was a part of the Kermanshah STEMI Registry. After applying inclusion criteria, a total of 2397 STEMI patients were assessed. The data were collected using a standardized case report form. Body mass index (BMI) (kg/m2) classified into underweight (<18.5), normal weight (18.5–24.9), overweight (25–29.9), class I/mild obese (30–34.9), and class II/extreme obese (≥35) categories. We assessed the independent predictors of the inhospital and one-year outcomes using multivariable logistic regression models.
Results: Out of the 2397 patients, 43 (1.79%) were underweight, 934 (38.97%) were normal, 1038 (43.30%) were overweight, 322 (13.43%) were class I obese, and 60 (2.50%) were class II obese. The results of crude analysis showed that the class I obesity had protective effect for CV death (OR 0.50; 95% CI 0.30-0.84), MACE3 (MI, stroke, and death) (OR 0.47; 95% CI 0.29-0.76), and MACE5 (MACE3 plus unstable angina and heart failure) (OR 0.59; 95% CI 0.44-0.79).
Conclusion: the protective effect of the class I obesity for death and MACE events, disappeared after multivariate adjustment. Therefore, this protective effect may not really exist and may actually reflect the effect of confounders such as age.