Psychometric Development and Internal Validation of a Short Version of the Crohn's Anal Fistula Quality of Life Scale

Perianal fistulizing Crohn's disease (PFCD) substantially impairs health-related quality of life (HRQoL). This prospective study aimed to validate the CAFQOL (Crohn's Anal Fistula-QoL) scale in an independent cohort and to develop a short version for disease monitoring in PFCD.

This prospective, multicenter study included patients with PFCD starting medical and/or surgical treatment. Patient-reported CAFQOL and Inflammatory Bowel Disease Questionnaire (32 items) (IBDQ-32), Fistula Drainage Assessment (FDA), Perianal Disease Activity Index (PDAI), and MRI Magnetic Resonance Novel Index for Fistula Imaging in CD (MAGNIFI-CD) were assessed at baseline, and weeks 9, 26, and 52. Psychometric properties were evaluated using classical test and item response theory; a short version was derived and internally tested.

Sixty-two patients were included with a mean CAFQOL of 59.8 (standard deviation [SD], 16.4) at baseline. CAFQOL improved significantly over time (P < .001, week 52 standardized response mean, -1.26). Convergent validity with IBDQ-32 was strong (r = -0.77; P < .001), whereas correlations with FDA, PDAI, and MAGNIFI-CD (r = -0.27-0.45; P < .001) were weak to negligible, supporting discriminant validity. Internal consistency was high (α = 0.89). Exploratory factor analysis revealed 2 subscales: social-practical impact and physical-emotional distress. Nine items with the strongest discrimination and coverage were selected for the short CAFQOL, which showed high reliability and strong correlation with the full scale. Deep remission corresponded with a CAFQOL score of 37 (range, 0-108), and a short CAFQOL score of 15 (range, 0-36). Median completion times for CAFQOL, short CAFQOL, and IBDQ-32 were 4, 1, and 5 minutes, respectively.

CAFQOL is a reliable and responsive tool that captures meaningful changes over time. The short CAFQOL is a feasible tool for repeated disease monitoring.