Obesity Paradox in Patients with Acute Coronary Syndrome: Is Malnutrition the Answer?

Obesity paradox has been reported in patients with cardiovascular disease, showing an inverse association between obesity as defined by body mass index (BMI) and prognosis. Nutritional status is associated with systemic inflammatory response and affects cardiovascular disease outcomes. The authors sought to examine the influence of obesity and malnutrition on the prognosis of patients with acute coronary syndrome (ACS). This study included consecutive patients diagnosed with ACS and underwent coronary angiogram between January 2009 and February 2023. At baseline, patients were categorized according to their BMI as follows: underweight (<18 kg/m2), normal weight (18-24.9 kg/m2), overweight (25.0-29.9 kg/m2), and obese (>30.0 kg/m2). We assessed the nutritional status by Prognostic Nutritional Index (PNI). Malnutrition was defined as a PNI value<38. Of the 21,651 patients with ACS, 582 (2.7%) deaths from any cause were observed over 28.7 months. Compared to the patient's state of normal weight, overweight and obesity were associated with a decreased risk of all-cause mortality. Malnutrition was independently associated with poor survival (HR 2.64, 95%CI 2.24-3.12, P<0.001). In malnourished patients, overweight and obesity showed a 39% and 72% reduction in the incidence of all-cause mortality, respectively. However, in nourished patients, no significant reduction in the incidence of all-cause mortality was observed (all P>0.05). Obesity paradox appears to occur in patients with ACS. Malnutrition may be a significant independent risk factor for prognosis in patients with ACS. The obesity paradox is influenced by the status of malnutrition.