Prognostic nutritional index and inflammatory indices as predictors of perioperative infection in patients with Cushing syndrome: a retrospective single-center study

Objective: Endogenous Cushing syndrome (CS) is associated with increased risk of morbidity and mortality, and infections are among its major complications. The aim of this study was to evaluate the predictive value of cortisol-related indices, blood cell-derived inflammatory indices, and the prognostic nutritional index (PNI) for perioperative infection and to identify risk factors. Methods: A total of 113 patients with confirmed CS were included: 71 pituitary CS, 37 adrenal CS, and 5 ectopic CS. ROC analysis was performed to evaluate predictors of infection. Multivariable models were constructed, and the best-performing model was selected as the final model. Results: Thirty-five CS patients (31%) developed infection. ROC analysis demonstrated that 1-mg DST (AUC = 0.852) and PNI (AUC = 0.845) were the strongest predictors of infection. In the final model, 1-mg DST ≥ 17.2 µg/dL (OR: 9.741; 95% CI: 2.801-33.883; P < 0.001), PNI ≤ 51.4 (OR: 9.569; 95% CI: 2.683-34.122; P < 0.001), the presence of diabetes mellitus (OR: 3.963; 95% CI: 1.128-13.925; P = 0.032), and presence of bone fracture(s) or a T-score ≤ -3 (OR: 3.574; 95% CI: 1.003-12.730; P = 0.049) were identified as independent risk factors for infection. Conclusion: Perioperative infection was associated with elevated cortisol and lower PNI levels in patients with CS. Assessment of 1-mg DST and PNI, in conjunction with diabetes mellitus status and bone health, may enhance the identification of high-risk patients and guide targeted preventive strategies.