Development of the Short Form for Chronic Hepatitis B Quality of Life Instrument (CHBQOL-SF) Using Delphi Method and Rasch Analysis

To refine the 23-item chronic Hepatitis B quality of life instrument (CHBQOL) using the modified Delphi method and Rasch model analysis, this study conducted a secondary data analysis on 578 chronic Hepatitis B (CHB) patients. The preliminary evaluation of the item's importance of the original CHBQOL and the final review of the short form of CHBQOL (CHBQOL-SF) were collected by the Delphi method. A bi-factor model was estimated and Rasch analysis with partial credit model was performed on each domain of the CHBQOL. Six items were suggested to remove based on the Delphi results. The fit of the bi-factor model was acceptable (RMSEA = 0.040; CFI = 0.983; TLI = 0.965). Disordered thresholds were initially found on three out of five items in Somatic symptoms, and four out of six items in Social stigma. Uniform differential item functioning was observed for three items for age group, two items for gender, and one item each for different ALT levels and HBV-DNA levels. Finally, the 10-item CHBQOL-SF retained the four-dimensional structure of the original instrument. The 10 items fit the Rasch model well and response options were set reasonably. The 10-item CHBQOL-SF would offer a brief and easily administrative CHB-specific patient-reported outcome measure for use in clinical practice and population studies.