To identify independent risk factors for postoperative urinary retention (POUR) following transabdominal preperitoneal inguinal hernia repair (TAPP), and to develop and evaluate a predictive model for POUR risk.

Clinical data of 598 patients who underwent TAPP for inguinal hernia in the Department of General Surgery, Affiliated Liupanshui People's Hospital of Zunyi Medical University, from January 2017 to December 2023 were retrospectively collected. Patients were randomly divided into a training cohort and a validation cohort at a ratio of 7:3. In the training cohort, patients were grouped into the POUR group (n=38) and the non-POUR group (n=381) according to the occurrence of POUR. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors for POUR, and a nomogram prediction model was constructed. Model performance was assessed in both cohorts. Discrimination was evaluated by calculating the area under the receiver operating characteristic (ROC) curve (AUC), calibration was assessed using calibration plots and the Hosmer-Lemeshow goodness-of-fit test, and clinical utility was analyzed using decision curve analysis (DCA).

Multivariate logistic regression analysis revealed that recurrence status (OR=0.279, 95% CI: 0.105-0.805; P=0.013), benign prostatic hyperplasia (BPH) (OR=15.09, 95% CI: 2.658-96.282; P=0.002), operative duration (OR=1.015, 95% CI: 1.006-1.023; P<0.001), and postoperative use of opioid analgesics (OR=2.224, 95% CI: 1.021-5.222; P=0.048) were independent risk factors for POUR after TAPP, whereas intraoperative urinary catheterization (OR=0.087, 95% CI: 0.012-0.370; P=0.004) was a protective factor. In terms of discrimination, the AUC was 0.763 (95% CI: 0.684-0.842; P<0.001) in the training cohort and 0.812 (95% CI: 0.677-0.947; P<0.001) in the validation cohort, both exceeding 0.75. Calibration assessment showed good agreement, with Hosmer-Lemeshow test results of χ²=5.566 (P=0.696) for the training cohort and χ²=11.132 (P=0.194) for the validation cohort.

Recurrent hernia, benign prostatic hyperplasia, absence of urinary catheterization, prolonged operative time, and postoperative opioid analgesic use are independent risk factors for POUR after TAPP. The nomogram model established based on these factors demonstrated good predictive performance and may assist clinicians in early identification of high-risk patients, enabling timely preventive and therapeutic interventions.