Application of the CDAS-QoL scale in surgical decision-making for anorectal stricture in Crohn's disease: a diagnostic accuracy study.

Anorectal stricture is a highly disabling complication of Crohn's disease (CD). However, surgical decisions still rely largely on symptoms and anal canal calibre, with no standardised quantitative threshold. Using the psychometrically validated Crohn's Disease Anorectal Stricture Quality of Life (CDAS-QoL) scale, we performed diagnostic accuracy analyses to link scores to multidisciplinary team (MDT)-defined surgical indication and derive a cut-off value for surgical risk stratification and shared decision-making. We conducted a single-centre diagnostic accuracy study in a retrospectively assembled cohort of patients with CD-associated anorectal stricture from January 2016 to November 2025. CDAS-QoL was prespecified as the index test, and MDT-defined surgical indication-based on symptoms, anal canal calibre, and imaging-served as the reference standard. A CDAS-QoL surgery-alert threshold was derived using receiver operating characteristic (ROC) analysis (Youden index) and a sensitivity-prioritised rule, and evaluated by bootstrap internal validation (1,000 resamples), stratified 5-fold cross-validation, and decision-curve analysis. Among 221 patients with CD-associated anorectal stricture, 57 (25.8%) underwent surgery after completing the CDAS-QoL. Baseline scores were higher in those who proceeded to surgery than in conservatively managed patients (85.3 ± 5.9 vs. 63.4 ± 15.2, p < 0.001). CDAS-QoL showed strong discrimination for MDT-defined surgical indication (AUC 0.89; 95% CI 0.85-0.93). A cut-off of 78.5 yielded 93% sensitivity and 81% specificity, classifying 84/221 (38.0%) as high risk. Internal validation (bootstrap and stratified 5-fold cross-validation) supported robustness, and decision-curve analysis suggested potential clinical utility. A threshold based on CDAS-QoL may identify patients with CD-associated anorectal stricture who have substantial functional impairment and should be prioritised for timely surgical evaluation, thereby facilitating shared decision-making.