Validity and reliability of the health-related questionnaire IBDQ-32 in Mexican patients with inflammatory bowel disease.

ABSTRACT

BACKGROUND: Inflammatory bowel disease comprises two conditions ulcerative colitis and Crohn's disease. Inflammatory Bowel Disease Questionnaire 32 (IBDQ-32) is a specific questionnaire which has been translated from English into Spanish and validated. In the Spanish-speaking countries of America it has not been validated. The aim was to determine the psychometric properties, validity and reliability of the Mexican version of the IBDQ-32 questionnaire. METHODS: A total of 316 patients with inflammatory bowel disease and 100 healthy controls participated in the study. The questionnaires IBDQ-32 and SF-36 were issued on two occasions (separated by 15 days). The psychometric properties of the Mexican version of the IBDQ-32 questionnaire were determined. RESULTS: Patients with inflammatory bowel disease had an impaired quality of life compared to healthy controls. There were no differences between ulcerative colitis and Crohn's disease in the total scores of IBDQ-32 and its domains. The internal consistency reliability was good. The intraclass coefficient showed good reliability (repeated measurement) for total scale and all four subscales. Factor analysis explained variance is higher than 50% therefore is considered adequate/acceptable. The correlation between IBDQ-32 and SF-36 showed a satisfactory association. The social domain is the only one that presented a ceiling effect. CONCLUSIONS: The Mexican version of the IBDQ-32 quality of life questionnaire is valid and reliable. This sample included the entire spectrum of inflammatory disease (remission and activity) and was comparable when assessing quality of life with the SF-36 generic questionnaire.