Risk Factors for Double-J Ureteral Stent Occlusion and an Exploratory Evaluation of Stent-Type Substitution in a Chronically Stent-Dependent Population: A Retrospective Cohort Study

Background/Objectives: Double-J (DJ) ureteral stents are prone to luminal occlusion, which causes renal dysfunction and complicates exchange. Risk stratification in chronically stent-dependent patients is poorly defined, and the management of confirmed occlusion is not standardised. We aimed to identify independent risk factors for DJ stent occlusion in a chronically stent-dependent population and to evaluate stent-type substitution at first confirmed occlusion. Methods: We conducted a single-centre retrospective cohort study at a tertiary urology service in Melbourne, Australia (January 2023 to December 2025). Patients requiring three or more sequential DJ replacements were eligible. Mechanical occlusion was defined as inability to pass a guidewire through the stent lumen at fluoroscopic exchange, an objective intraoperative surrogate; clinical failure events (nephrostomy conversion, septic admission, or acute kidney injury requiring intervention) were recorded separately. Midstream urine culture and pre-exchange renal ultrasound were obtained at each visit. Cox proportional hazards modelling with robust patient-level clustering was performed. Results: We analysed 125 ureters (97 patients) over a mean follow-up of 20.6 months. Occlusion occurred in 55 ureters (44.0%). Four predictors were robust to Bonferroni correction: indwelling urethral catheter (hazard ratio [HR] 4.62), urinary stone disease versus malignant disease (HR 4.02), retroperitoneal fibrosis versus malignant disease (HR 3.24), and bacteriuria at exchange (HR 2.76). Two further associations, Eastern Cooperative Oncology Group (ECOG) performance status 2 to 4 (HR 2.31) and prior pyelonephritis (HR 1.89), did not survive correction and are exploratory. After stent-type substitution at first occlusion, 43 of 55 ureters (78.2%) had no further occlusion without interval shortening. Summer accounted for 45.1% of events (p < 0.001). Conclusions: In chronically stent-dependent patients, several factors were independently associated with DJ stent occlusion, four of them robust to multiple-comparison correction. Stent-type substitution was associated with occlusion-free outcomes in most cases without interval shortening; because the analysis was uncontrolled and regression to the mean cannot be excluded, this observation is hypothesis-generating. All hazard estimates are exploratory in view of an events-per-variable ratio below ten and a survivor-selected cohort, and apply only to patients with established chronic stent dependency. Prospective randomised evaluation is warranted.