An obesity paradox in patients with myocardial infarction undergoing percutaneous intervention

Abstract Background and Aims Data concerning the relationship between body mass index (BMI) and outcome in myocardial infarction (MI) patients are inconclusive. Long-term data on the influence of BMI on survival in patients with MI who have undergone percutaneous intervention (PCI) are lacking. We aimed to assess the effect of different categories of BMI on long-term mortality. Methods and Results A single-center retrospective study of 6496 patients with MI who underwent PCI, was performed. Patients were divided into six categories according to their BMI and these were compared. All-cause mortality was assessed over a median period of 6.0 years. An inverse J-shaped relationship was observed between BMI and long-term mortality. The lowest mortality was observed in patients with class I obesity. The patients with a BMI below 25.0kg/m2 were more likely to die than patients with class I obesity. A gradual decrease in BMI below 25.0kg/m2 was associated with a progressively increased risk of dying, with the underweight patients showing a 2.18-fold increase in mortality risk. An obesity paradox was present. In addition, the patients with class III obesity had a more than 70% higher long-term mortality risk compared to the reference group. Both lower and higher degrees of BMI were found to be harmful in patients suffering MI who underwent PCI. Conclusion The obesity paradox was present in a very long-term follow-up of patients suffering MI who underwent PCI. However, both lower and higher BMI values are harmful, and an inverse J-shaped relationship between BMI and outcome was observed.