Development and validation of a primary sclerosing cholangitis-specific health-related quality of life instrument: CLDQ-PSC

Objectives: To understand the full impact of primary sclerosing cholangitis (PSC) on patients' health, it is important to assess their health-related quality of life (HRQL). Using the Chronic Liver Disease Questionnaire (CLDQ), we aimed to develop and validate a PSC-specific HRQL instrument. Methods: Previously collected clinical and patient-reported outcome data from PSC patients were used. The original CLDQ with 29 items was subjected to item reduction, followed by factor analysis. A standard HRQL instrument validation pipeline was then applied to the new CLDQ-PSC. Results: There were 100 PSC patients (44 +/- 13 y, 32% male, 79% college educated, 39% cirrhosis, 67% inflammatory bowel disease, 66% ulcerative colitis, and 50% on ursodeoxycholic acid After item reduction and exploratory factor analysis, there were 24 items and 5 factors left; based on factor loadings, the factors were named emotional function, fatigue, symptoms, worry, and sleep. Internal consistency assessment returned Cronbach alpha 0.85-0.94, item-to-own domain correlations > 0.66 for 22/24 items. Known-groups validity suggests discrimination between PSC patients with and without cirrhosis or its complications, obesity, history of depression, weight loss, and PSC patients on versus not on ursodeoxycholic acid (p < 0.05 for all or select CLDQ-PSC domains). Relevant items of Short Form-36 and CLDQ-PSC were highly correlated (all p < 0.0001). Matching with items of another PSC-specific instrument (PSC-patient-reported outcome; 42 items) for relevance and redundancy suggests that CLDQ-PSC is a relevant, comprehensive, and short HRQL instrument, which can be used for patients with PSC. Conclusions: The CLDQ-PSC is a PSC-specific HRQL instrument that was developed using an established methodology and demonstrated good psychometric characteristics.