A short version of a HRQoL questionnaire for Italian and Japanese patients with PBC☆

Received 29 October 2009; accepted 7 January 2010. published online 17 February 2010.
Corrected Proof

Abstract

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.

Abbreviations: PBC, primary biliary cirrhosis, HRQoL, health related quality of life, CFA, confirmatory factor analysis, CFI, comparative fit index, GFI, goodness of fit index, AGFI, adjusted goodness of fit index, RMSEA, root mean square error of approximation, CAIC, consistent Akaike's information criterion

Keywords: Factor structure, PBC-40, Principal component analysis, Quality of life

a Department of Psychology, University of Milano-Bicocca, Milan, Italy

b Department of Medicine, Teikyo University School of Medicine, Tokyo, Japan

c Division of Gastroenterology and Hepatology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan

d Division of Internal Medicine and Liver Unit, San Paolo Hospital School of Medicine, University of Milan, Milan, Italy

e Division of Gastroenterology, Graduate School of Medicine, Tohoku University, Sendai, Japan

f Division of Internal Medicine and Hepatobiliary Immunopathology Unit, IRCCS Istituto Clinico Humanitas, Via A. Manzoni 113, 20089 Rozzano, Italy

g Department of Translational Medicine, University of Milan, Milan, Italy

h Division of Gastroenterology and Hepatology, Mayo Clinic and Foundation, Rochester, Minnesota, United States

Corresponding author. Tel.: +39 02 8224 5128; fax: +39 02 8224 5191.

☆ Grant support: Supported by Executive Program of Cooperation in the Field of Science and Technology between the Government of Italy and the Government of Japan.

1 These authors equally contributed to this work.

2 Members of the Italian-Japanese PBC Study Group contributed equally and are listed in Appendix A.

PII: S1590-8658(10)00008-3

doi:10.1016/j.dld.2010.01.004