P0535 Crohn’s Anal Fistula - Quality of Life (CAFQOL) for disease control and remission in patients with perianal fistulizing Crohn’s disease: a new standard in assessing clinical outcome?

Abstract Background Perianal Fistulizing Crohn’s Disease (PFCD) has a major impact on quality of life (QOL). QOL improvement is a key clinical goal, whether the aim is surgical repair, or symptom control. This prospective study evaluated the CAFQOL (Crohn’s Anal Fistula-QOL) questionnaire for disease monitoring in PFCD patients. Methods This study included patients with PFCD starting on anti-TNF therapy, mesenchymal stem cell injection, or hyperbaric oxygen therapy followed by surgical closure. We collected patient-reported CAFQOL and IBDQ-32, as well as Fistula Drainage Assessment (FDA), Perianal Disease Activity Index (PDAI) and MRI (MAGNIFI-CD) outcomes at baseline, and at weeks 9, 26, and 52. QOL changes over time were analyzed using a linear mixed-effects model, and correlations between outcomes were assessed using Spearman correlation coefficients. Internal consistency was assessed with Cronbach’s alpha. The underlying structure of CAFQOL was evaluated with exploratory factor analysis (EFA) to identify distinct dimensions of quality of life. Responsiveness of CAFQOL and PDAI were reported in standardized response mean (SRM). Target CAFQOL values at week 52 for patients in complete remission by week 26 (PDAI≤4, MAGNIFI-CD=0) were calculated with a linear mixed-effects model. Receiver Operating Characteristic (ROC) model was used to evaluate CAFQOL in relation to clinical remission (FDA). Results We included 62 patients with a mean CAFQOL of 59.8 (SD 16.4) at baseline (Table 1). CAFQOL showed significant improvement over time, with average improvements of 8 points (95% CI 4 – 11) at week 9, 12 points (95% CI 8 - 16) at week 26, and 22 points (95% CI 18 - 26) at week 52 (all p<0.0001) (Figure 1). CAFQOL was strongly correlated with IBDQ-32 (r = -0.78; p<0.001) supporting convergent validity, while correlations with FDA (r = 0.48; p<0.0001), PDAI (r = 0.33; p=0.131), and MAGNIFI-CD (r = 0.11; p=0.548) were weak to negligible, supporting discriminant validity. A Cronbach’s alpha of 0.80 supported internal consistency. EFA revealed three main factors: social-practical impacts, emotional-mental health impacts, and physical discomfort explaining 53% of the QOL variance. By week 52, SRM of CAFQOL and PDAI were -1.26 and -1.79 respectively, suggesting large effect sizes. CAFQOL ≤ 37 was associated with complete fistula remission (PDAI≤4, MAGNIFI-CD=0), and was able to detect clinical remission with 80% (95% CI: 58–92) sensitivity and 56% (95% CI 39–71) specificity (AUROC=0.735; p=0.0038). Conclusion The CAFQOL is a reliable and consistently responsive tool that captures meaningful changes in quality of life over time regardless of the treatment modality.