Development and Validation of the Japanese Version of the Anal Fistula Quality of Life Scale (AF-QoL)

Abstract

Objectives: This study aimed to evaluate the psychometric properties of the Japanese version of the cryptoglandular Anal Fistula Quality of Life Scale (AF-QoL), a 22-item instrument scored from 0 to 100, where higher scores indicate better quality of life.

Methods: The AF-QoL was translated into Japanese followed by linguistic validation. The validated version was administered to 110 consecutively recruited patients with anal fistula, who completed the questionnaire at baseline and again after 2–3 weeks. At baseline, patients also completed the Perineal Disease Activity Index (PDAI), Hospital Anxiety and Depression Scale (HADS), and Short Form-12 Health Survey (SF-12). Psychometric properties were assessed in terms of internal consistency (Cronbach's alpha), construct validity (Pearson's correlation coefficients), and responsiveness.

Results: Internal consistency was high (Cronbach's alpha = 0.92). Construct validity was supported by correlations with PDAI (–0.37), HADS anxiety (–0.46) and depression (–0.47) subscales, and the SF-12 Mental Component Summary (0.19). In the retest analysis, 83 of 106 patients (78%) reported stable symptoms, and the test–retest correlation coefficient was 0.93, indicating excellent reliability. Symptom changes were reported in 23 patients (22%), and significant differences between test and retest scores were observed among those reporting improvement or worsening (P < 0.05, paired t test), demonstrating responsiveness. Notably, many patients reported substantial negative impacts on interpersonal relationships and psychosocial well-being.

Conclusions: The Japanese version of the AF-QoL demonstrated good linguistic validity and favorable psychometric properties, supporting its use for assessing quality of life in patients with anal fistula.