Nutritional Status and Obesity Paradox in Acute Coronary Syndrome Patients

The worse nutritional status of patients without obesity after an acute coronary syndrome (ACS) could explain their worse prognosis and the so-called obesity paradox. We performed a retrospective study of all consecutive patients admitted to a hospital for ACS between 2009 and 2020. Nutritional status was analyzed using the CONUT scale, and values > 4 were categorized as moderate-severe malnutrition. We included 2789 patients with a mean BMI of 28.0 (4.6) kg/m² and 26.4% with obesity. The mean CONUT index was 2.4 (2.2), and 24.3% had moderate-severe malnutrition. Obese patients had a lower prevalence of moderate-severe malnutrition: 20.0% vs. 25.9% (p = 0.003). The median follow-up was 3 years. A significant interaction between BMI and the CONUT for mortality was verified, and both variables behaved in the opposite way in relation to risk. BMI was associated with lower all-cause (HR: 0.93, 95% CI 0.89-0.98) and cardiovascular (HR: 0.93, 95% CI 0.87-0.98) mortality risk only in patients with CONUT > 4; however, in patients without malnutrition, BMI obesity was not associated with increased mortality or major cardiovascular events. In conclusion, CONUT-defined nutritional-inflammatory status may partly contribute to the observed obesity paradox in ACS patients.