Validation of a Primary Biliary Cholangitis-Specific Version of Chronic Liver Disease Questionnaire: CLDQ-PBC.

INTRODUCTION

Primary biliary cholangitis (PBC) is a chronic liver disease, leading to cirrhosis and impairment of patient-reported outcomes. 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.

METHODS

From our Liver Database, we included patients with PBC who had CLDQ, clinicolaboratory data, and completed Short Form-36 and The Functional Assessment of Chronic Illness Therapy-Fatigue. The 29 items of CLDQ were subjected to item reduction, exploratory factor analysis, and fed into a standard instrument validation pipeline.

RESULTS

Data were available for 108 patients with PBC: 57 ± 11 years, 7% male, 58% cirrhosis, and 24% decompensated cirrhosis (Child 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, and Worry). Good to excellent internal consistency (Cronbach's α 0.85-0.93) was observed for 5/7 domains. For the remaining 2 domains (Diet and Itch), additional items obtained from patients, experts, and review of the literature were included. For 5 domains, known-group validity tests discriminated between patients with PBC with and without cirrhosis, advanced cirrhosis, and depression ( P < 0.05 for 3-5 domains). The CLDQ-PBC domains were correlated with relevant domains of Short Form-36, CLDQ-PBC Fatigue correlated with Fatigue Scale of Functional Assessment of Chronic Illness Therapy-Fatigue (rho = +0.85), and CLDQ-PBC Worry domain negatively correlated with alkaline phosphatase (rho = -0.38, P = 0.0082).

DISCUSSION: 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.