Cross-cultural validation and reliability of the Turkish version of the anal fistula quality of life scale for cryptoglandular anal fistula

Abstract

The aim of this study was to adapt and validate the Cryptoglandular Anal Fistula Quality of Life (AF-QoL) scale for Turkish-speaking patients, providing a disease-specific, patient-reported outcome measure (PROM) to assess quality of life (QoL) in cryptoglandular anal fistula. Methods: A prospective, multicenter, cross-sectional study was conducted across seven tertiary centers in Türkiye. The 22-item AF-QoL scale, originally validated in English, was translated and culturally adapted into Turkish following Consensus-Based Standards for the Selection of Health Measurement Instruments (COSMIN) guidelines, including expert consensus and a pilot study (n = 10). A total of 220 Turkish-speaking adults with cryptoglandular anal fistula completed the scale. Structural validity was evaluated using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). Internal consistency was assessed using Cronbach’s alpha, and item–total correlations. Test–retest reliability was evaluated in a clinically stable subgroup of patients. Results: EFA confirmed a six-domain structure, comprising psychological impact, everyday activities, unpredictability/disease control, seton-related issues, social limitations, and discharge/discomfort, explaining 69.2% of the total variance. CFA demonstrated an acceptable overall model fit (χ2/df = 1.94, root mean square error of approximation [RMSEA] = 0.048, Comparative Fit Index [CFI] = 0.945, standardized root mean square residual [SRMR] = 0.035). The Turkish AF-QoL demonstrated high internal consistency (Cronbach’s α = 0.828), satisfactory item–total correlations (r = 0.32–0.76), and good test–retest reliability (intraclass correlation coefficient = 0.74), indicating temporal stability. Conclusions: The Turkish version of the AF-QoL demonstrates satisfactory reliability and structural validity for use in Turkish patients with cryptoglandular anal fistula. This cross-cultural validation provides a disease-specific PROM suitable for clinical and research applications. Further studies assessing additional measurement properties, including structural validity, measurement error, and responsiveness, are warranted. Clinical trial registration: This study was not a clinical trial and thus was not registered in a clinical trial registry.