Validation of the English version of the difficulty of life scale for patients with ulcerative colitis

Objective Patients with ulcerative colitis have abdominal symptoms that affect their quality of life in multiple ways. The difficulty of life scale was developed in Japan to measure these patients' degree of daily difficulties. We aimed to assess this scale for English-speaking patients and to evaluate its validity and reliability. Methods The original Japanese version of the difficulty of life scale was translated into English and administered to 100 consecutive outpatients with ulcerative colitis at a university hospital in London. Medical information was obtained from participants' medical records. Factor validity, construct validity using the Short Inflammatory Bowel Disease Questionnaire, known group validity with clinically different groups, internal consistency and test-retest reliability were analyzed statistically. Results Three factors were extracted by exploratory factor analysis, as in the original scale. The construct validity was supported by the association between the Difficulty of Life Scale and Short Inflammatory Bowel Disease Questionnaire scores (Pearson's correlation coefficient: 0.73-0.83). Patients with visible bleeding or who were prescribed corticosteroids reported significantly greater difficulty than did those without them, demonstrating a significant effect size. The scaling success rate was acceptable. Internal consistency was confirmed (Cronbach's alpha: 0.68-0.89). The intraclass correlation coefficients were >0.75, thus confirming the test-retest reliability. Conclusion The English version of the difficulty of life scale is a reliable and valid disease-specific scale for ulcerative colitis. It can be used to communicate the challenge of daily living between patients with this long-term condition and health care providers.