Unmasking Risk Behind the Obesity-Paradox Signal: Prognostic Value of CONUT Score Combined with BMI.

The "obesity paradox" suggests better outcomes in overweight cardiovascular patients, yet the prognostic role of poor nutritional status-even in obese individuals-remains unclear. We evaluated whether combining body mass index (BMI) with the Controlling Nutritional Status (CONUT) score refines interpretation of the obesity-paradox signal in patients undergoing percutaneous coronary intervention (PCI).We analyzed 631 SAKURA-PCI2 Registry patients (2020-2022) and classified them into four groups: Group 1 (CONUT 0-1/BMI < 25 kg/m2), Group 2 (CONUT 0-1/BMI ≥ 25 kg/m2), Group 3 (CONUT ≥ 2/BMI < 25 kg/m2), and Group 4 (CONUT ≥ 2/BMI ≥ 25 kg/m2). The endpoint comprised all-cause death, myocardial infarction, stent thrombosis, heart-failure hospitalization, major bleeding, stroke, and venous thromboembolism. Over a median follow-up of 2.4 years, 123 events occurred (19.5%). Malnutrition (Groups 3 and 4) was associated with higher risk regardless of BMI. Among non-malnourished patients, obese individuals (Group 2) had fewer events than non-obese peers (Group 1), but this was not significant after multivariable adjustment. In adjusted models, risk was highest in Group 4 (hazard ratio [HR] 2.25, 95% confidence interval [CI] 1.01-5.00, P = 0.047) and Group 3 (HR 2.18, 95% CI 1.03-4.59, P = 0.041) versus Group 2.An obesity-paradox signal was observed primarily in nutritionally preserved patients, whereas outcomes in malnourished patients were driven by malnutrition rather than obesity. Accordingly, the obesity paradox should not be taken as evidence that obesity is protective, and nutritional assessment, including the CONUT score, may complement BMI for post-PCI risk stratification.