A short version of a HRQoL questionnaire for Italian and Japanese patients with Primary Biliary Cirrhosis

Background: The available self-report questionnaire for the quality of life in patients with primary biliary cirrhosis (PBC-40) is currently validated only in the British population but it lacks an evaluation of its dimensionality. Aims: To validate the Italian and Japanese versions of PBC-40 and to assess the dimensionality of the original structure of PBC-40 by a confirmatory factor analysis. PBC-40 was translated to Italian and Japanese using the forward-backward method and then reviewed in focus groups in the framework of a large multicentric study. Methods: A sample of 290 patients with PBC (125 Italian and 165 Japanese) was administered two questionnaires previously validated for PBC-specific (PBC-40) and general quality of life (SF-36). Results: The confirmatory model failed to fit adequately the original hypothesized structure. A principal component analysis led to a seven-factor structure, with exclusion of 13 items characterized by lower load; PBC-27 questionnaire was the final instrument. The validity of the PBC-27 was supported by its strong correlation with the SF-36 scores. Conclusion: We here propose an alternative structure of the quality of life questionnaire for PBC, namely PBC-27, which appears to be effective in detecting the impact of PBC on quality of life in Italian and Japanese patients.