P0240 Cross-cultural adaptation and validation of the Crohn’s Anal Fistula – Quality of Life scale in Dutch patients with active perianal fistulizing Crohn’s disease
Authors: Bak M T J , Pierik R J , Rizopoulos D , Buskens C J , van der Bilt J D W , de Boer N K H , Gecse K B , Mundt M W , Witjes C D M , Fitzpatrick C E , Nissen L H C , Verdaasdonk E G G , Hoogenboom F J , Visschedijk M C , Stassen L P S , van Ruler O , de Vries A C ,   Dutch Initiative on Crohn and Colitis and the Dutch Initiative on Crohn and Colitis – Surgery
Published: January 2025

Abstract

Background
Perianal fistulizing Crohn’s disease (pCD) is associated with debilitating symptoms such as fecal incontinence and perianal pain, and can significantly impact a patient’s quality of life (QoL)1. The Crohn’s Anal Fistula Quality of Life (CAF-QoL) scale has recently been developed as the first disease-specific patient-reported outcome measure for patients with pCD2, but has yet to be validated in an independent cohort. Therefore, we aimed to adapt and validate the CAF-QoL scale in a Dutch cohort of patients with active pCD.

Methods
Patients with active pCD were retrieved from a prospective multicenter study performed in 41 Dutch (non-)academic hospitals between September 2022 and March 2023. Respondents of the CAF-QoL scale and other health-related QoL questionnaires (sIBDQ and EQ-5D-5L3,4) at baseline were included. After translation of the CAF-QoL scale to Dutch, patient representatives verified the questionnaire’s comprehensibility. Prospective validation comprised the assessment of construct validity, internal consistency, test-retest reliability and responsiveness. Item response theory (IRT) was used to investigate the discriminative power of individual CAF-QoL items and to test for differential item functioning (DIF), examining whether each item behaves equally across all respondents.

Results
Questionnaires were completed by 264 patients (response rate 64%; female 56%) (Table 1). The median pCD duration at inclusion was 3.0 years (IQR 1.0 – 8.0). Evaluation of construct validity found a moderate correlation between CAF-QoL and sIBDQ (r -0.61, p&lt;0.01) and EQ-5D-5L (r -0.58 [utility] and r -0.42 [VAS], p&lt;0.01) scores. Furthermore, the CAF-QoL scale demonstrated excellent internal consistency (Cronbach’s alpha 0.93), good stability (intraclass correlation coefficient 0.83) and responded well to improvement and worsening of pCD symptoms (p&lt;0.01)(Table 2). Discrimination values revealed that most items (73%) possessed a moderate to high ability to predict poor QoL; items pertaining to the impact of pCD on daily life had the greatest predictive abilities. No clinically relevant DIF was found among patients of different ages, sexes or education levels.

Conclusion
In this prospective multicenter study, the CAF-QoL scale was validated as a robust tool to measure pCD-specific QoL among Dutch patients with active pCD. Therefore, this scale appears to be well suited for use in clinical practice. Further studies are required to establish a minimal clinically important difference for the CAF-QoL scale; this would determine the smallest change in test scores perceptible to the patient, enabling effective monitoring of treatment outcomes.

References
1.Panes J, Reinisch W, Rupniewska E, et al. Burden and outcomes for complex perianal fistulas in crohn's disease: Systematic review. World J Gastroenterol 2018;24:4821-34
2.Adegbola SO, Dibley L, Sahnan K, et al. Development and initial psychometric validation of a patient-reported outcome measure for Crohn's perianal fistula: the Crohn's Anal Fistula Quality of Life (CAF-QoL) scale. Gut. 2021;70(9):1649-1656.
3.Irvine EJ, Zhou Q, Thompson AK. The Short Inflammatory Bowel Disease Questionnaire: a quality of life instrument for community physicians managing inflammatory bowel disease. CCRPT Investigators. Canadian Crohn's Relapse Prevention Trial. Am J Gastroenterol. 1996;91(8):1571-1578.
4.Herdman M, Gudex C, Lloyd A, et al. Development and preliminary testing of the new five-level version of EQ-5D (EQ-5D-5L). Qual Life Res. 2011;20(10):1727-1736.