Characterisation of the associations and impact of symptoms in primary biliary cirrhosis using a disease specific quality of life measure

Background/Aims Primary biliary cirrhosis (PBC) patients experience significant impairment to quality of life (QOL). Studies to date examining relative contributions of different symptoms to QOL impairment in PBC, and biological associations have been limited by the unavailability of appropriate disease specific symptom quantification modalities. Methods We applied the PBC-40, a recently developed, multi-domain disease specific QOL measure, to 54 PBC patients to explore the inter-relationship of different symptoms, their biological associations, and correlation with physical functioning measured by accelerometry. Results Two discrete and unrelated symptom complexes in PBC were identified focused on fatigue (together with cognitive and emotional dysfunction and other symptoms) and itch, with social dysfunction associating with both complexes. We confirmed no correlation between symptom severity and biological parameters of disease severity. There was a strong inverse correlation between physical activity (assessed over 6 days) and fatigue (P<0.005), but not between physical activity and Itch. Patients averaging <7500 steps per day had over 75% higher fatigue scores than patients averaging >7500 steps. Conclusions We have demonstrated two independent symptom complexes in PBC centred around fatigue and itch, neither is associated with biological parameters of activity, and the fatigue-centred complex is associated with objective impairment of physical functioning.