Abstract:Fatigue is a significant problem that affects over 50% of patients with the autoimmune liver disease Primary Biliary Cirrhosis (PBC).To understand the biological basis of fatigue in PBC and to develop...Fatigue is a significant problem that affects over 50% of patients with the autoimmune liver disease Primary Biliary Cirrhosis (PBC).To understand the biological basis of fatigue in PBC and to develop effective interventions, it is important that fatigue can be quantified accurately and reliably in PBC.Patient reports emphasise a perception that they experience "good days and bad days" suggesting the possibility of interday variability.The issue of variability in perception of fatigue during the course of the day has never been addressed.In this study we set out to address intra-and inter-day variability in fatigue perception in PBC to further inform the design of studies involving fatigue quantification in PBC and to help us to advise patients with regard to coping strategies.Sixteen female PBC patients and a fatigued control group of 25 CFS/ME (defined using Fukuda criteria) completed fatigue diaries.Subjects rated their fatigue on a scale of 0 (no fatigue) to 10 (severe fatigue) 4 times a day, each day for 5 weeks.In both PBC and CFS/ME there was no significant difference in perceived fatigue from week to week, or day to day.There were also no differences between week days and weekends or in the variability within days when considered between days.In PBC there was however a progressive and significant increase in perceived fatigue through each day, with mean ± SD fatigue scores of 3.2 ± 2 at breakfast increasing to 5.5 ± 2 at bedtime (p<0.001).This was in contrast to the CFS/ME population where fatigue was high in the morning (6.4 ± 2) lower at lunchtime (p<0.05), then increasing to 7 ± 2 at bedtime.Fatigue appears to be lowest in the morning in PBC increasing through the day which differs from the pattern seen in CFS/ME.This suggests that the biological mechanisms in the two fatigue associated diseases may be different.Furthermore, when assessing fatigue, it is important that this variability is considered and therefore assessment tools must be completed at a standardized time of day in PBC.Advising patients to plan their days, with a focus on performing activities in the morning if possible may help them to manage their symptoms.Read More