Development and validation of a nomogram model for predicting acute urinary retention after transrectal prostate biopsy.

Background: Post-biopsy acute urinary retention (AUR) is still a common complication, often leading to extended hospital stays and greater patient discomfort. This study aimed to develop and validate a nomogram for the early identification of AUR after transrectal prostate biopsy (TRPB). Methods: We collected data on patients who underwent TRPB at The Third Affiliated Hospital of Sun Yat-sen University between January 2019 and November 2023, including all characteristics and prostate morphological parameters. A total of 403 patients were screened for eligibility, and after strict screening, 333 patients were included in the study. These patients were randomly divided into a development cohort (n=233) and a validation cohort (n=100) in a 7:3 ratio. Moreover, the International Prostate Symptom Score (IPSS) and quality of life (QoL) before and after biopsy were collected for 66 patients with AUR with varying post-void residual urine volumes (PVR). Additionally, the voiding situation after catheter removal was also documented. Univariate and multivariate logistic regression analyses were used to identify independent risk factors for AUR. The performance of the nomogram was assessed via calibration curves, Harrell's concordance index (C-index), decision curve analysis (DCA), and clinical impact curve (CIC) analysis. Results: The PVR (200-300 mL) group showed significantly lower IPSS and QoL on post-biopsy day 7 compared to the 301-500 mL and >500 mL groups (P<0.05 and P<0.001, respectively). Additionally, the PVR (200-300 mL) group had the highest urinary catheter removal success rate. Univariate and multivariate logistic regression analyses identified 3 clinical factors-hypercholesteremia, prostatic urethral length (PUL), and the prostatic urethral angle (PUA)-that are significantly correlated with the AUR. This nomogram exhibited strong discriminative ability in both the development and validation cohorts, with an area under the curve (AUC) of 0.834 [95% confidence interval (CI): 0.772-0.896] in the development cohort and an AUC of 0.895 (95% CI: 0.831-0.958) in the validation cohort. The Hosmer-Lemeshow test indicated a well-fitted calibration curve (P=0.69). Furthermore, DCA and the CIC suggested favorable clinical utility for the nomogram. Conclusions: Here, we first determined that patients unable to void with a PVR >200 mL should be considered as having AUR and developed a nomogram to predict its occurrence, facilitating individualized medical treatment after TRPB.