Impact of Histopathology and Bladder Dysfunction on the Treatment Strategy Selection of Ketamine‐Associated Cystitis

OBJECTIVE: To investigate predictors for selecting an appropriate treatment strategy for ketamine-associated cystitis (KC) due to chronic ketamine abuse for entertainment. METHODS: This retrospective study included 62 patients with KC who underwent baseline videourodynamics and bladder cold-cup biopsy; 43 subsequently underwent AE and 19 continued conservative treatment. Histopathology-urodynamic associations were assessed using Spearman correlations. A parsimonious logistic model evaluated factors associated with subsequent AE. The exploratory five-item histopathological score was assessed in complete cases with bootstrap resampling. RESULTS: , and voided volume, while cystoscopic maximal bladder capacity was not significantly different (p = 0.085). Urothelial denudation severity correlated with lower first sensation (ρ = -0.36, p = 0.017) and fullness sensation (ρ = -0.49, p < 0.001). In the multivariable model (N = 44), higher voided volume was associated with lower odds of AE (OR: 0.72 per 10 mL, 95% CI: 0.57-0.90, p = 0.004), whereas severe urothelial denudation was associated with higher odds (OR: 27.24, 95% CI: 1.73-428.36, p = 0.019). The complete-case score (N = 50) had AUC 0.941 (bootstrap 95% CI: 0.875-0.988); cutoff ≥ 2 yielded 94.4% sensitivity and 78.6% specificity. CONCLUSION: Lower voided volume and severe urothelial denudation were associated with subsequent AE. The composite histopathological score is exploratory and requires external validation.