IL6 and nutritional deficiency disease: In the regression model, the change in IL-6 levels between POD 0 and POD 1 (coefficients = 0.01 for every 1 pg/mL increment; 95% confidence interval: 0.01–0.02; P = 0.037) and high malnutrition risk (coefficients = 2.80; 95% confidence interval: 1.45–3.52; P = 0.041) were significantly associated with changes in fatigue scores.