Objective To investigate the factors influencing the need for surgical intervention after percutaneous catheter drainage (PCD) in patients with infected necrotizing pancreatitis (INP), and to construct and validate a nomogram-based predictive model. MethodsA total of 197 INP patients who underwent PCD at the Second Hospital of Lanzhou University between January 2021 and December 2023 were retrospectively enrolled. Patients were randomly divided into a training cohort (n=137) and a validation cohort (n=60) in a 7∶3 ratio. Univariate and multivariate logistic regression analyses were performed in the training cohort, and a nomogram was developed based on the multivariate results. Model discrimination was evaluated using receiver operating characteristic (ROC) curves, calibration was assessed using calibration plots, and clinical utility was examined using decision curve analysis (DCA) in both cohorts. ResultsMultivariate logistic regression revealed that C-reactive protein (CRP) [OR=1.028, 95%CI (1.005, 1.051), P=0.015], neutrophil-to-lymphocyte ratio (NLR) [OR=1.876, 95%CI (1.240, 2.839), P=0.003], computed tomography severity index (CTSI) [OR=6.701, 95%CI (2.827, 15.884), P<0.001], and acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score [OR=1.353, 95%CI (1.075, 1.703), P=0.010]were independent predictors of surgical intervention after unsuccessful PCD. A nomogram was constructed accordingly. The areas under the ROC curve (AUCs) of the predictive model were 0.95 [95%CI (0.92, 0.98)]in the training cohort and 0.94 [95%CI (0.88, 0.99)]in the validation cohort. Calibration curves and Hosmer-Lemeshow goodness-of-fit tests demonstrated good agreement between predicted and observed outcomes (training cohort P=0.633, validation cohort P=0.236). DCA showed that the nomogram provided the greatest net clinical benefit within threshold probabilities of 5%–97% in the training cohort and 10%–95% in the validation cohort. ConclusionsThe predictive model which including CRP, NLR, CTSI score and APACHE II score has significant predictive value of surgical intervention following PCD failure in INP patients. The proposed nomogram offers a reliable tool for early identification and clinical decision-making in this population.