Development of a Primary Biliary Cholangitis-specific Version of Chronic Liver Disease Questionnaire: CLDQ-PBC.

Abstract

Primary biliary cholangitis (PBC) is a chronic liver disease leading to cirrhosis and impairment of patient-reported outcomes (PROs). We aimed to develop a PBC-specific version of the Chronic Liver Disease Questionnaire (CLDQ) instrument to assess health-related quality of life of patients with PBC. From our Liver Database, we included patients with PBC who had CLDQ, clinico-laboratory data, and completed Short Form-36 (SF-36) and The Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F). The 29 items of CLDQ were subjected to item reduction, exploratory factor analysis, and fed into a standard instrument validation pipeline. Data were available for 108 PBC patients: 57±11 years, 7% male, 58% cirrhosis, 24% decompensated cirrhosis (Child's B and C). Of 29 CLDQ items, none met the exclusion criteria. Exploratory factor analysis (95% of variance) returned 7 factors. Based on evaluation of factor loadings and face validity, those factors yielded 7 domains (Diet, Emotion, Fatigue, Itch, Symptoms, Sleep, Worry). Good to excellent internal consistency (Cronbach's alpha 0.85-0.93) was observed for 5/7 domains. For the remaining two domains (Diet, Itch), additional items obtained from patients, experts and review of the literature were included. For 5 domains, known-groups validity tests discriminated between PBC patients with and without cirrhosis, advanced cirrhosis, depression (p<0.05 for 3-5 domains). The CLDQ-PBC domains were correlated with relevant domains of SF-36, CLDQ-PBC Fatigue correlated with Fatigue Scale of FACIT-F (rho=+0.85) and CLDQ-PBC Worry domain negatively correlated with alkaline phosphatase (rho=-0.38, p=0.0082). The CLDQ-PBC has been developed based on the original CLDQ. The new instrument has evidence for internal consistency and validity, and is being fully validated using an external cohort.