Validation of a fatigue impact score in primary biliary cirrhosis: towardsa standard for clinical and trial use

Background/Aims: Fatigue is the commonest symptom of the chronic liver dise ase primary biliary cirrhosis (PBC), PBC is increasingly being diagnosed ea rlier in its natural history at a stage when concerns about progression to liver failure may be less prominent than current symptoms. The importance o f symptomatic treatment is therefore increasingly being recognised, Researc h into the aetiology and treatment of fatigue in PBC has been hampered by t he lack of relevant, reproducible measures of fatigue severity. The aim of this study was to validate the Fish Fatigue Severity Score (FFSS), a measur e of the impact of fatigue on daily living, for use in PBC and to use the F FSS to study the severity and correlates of fatigue in this condition, Methods: Fifty-eight patients with PBC and 31 matched control patients atte nding hospital for nonhepatic disease were studied. The reproducibility of FFSS was assessed over periods from 1 hour to 1 month. Fatigue, as measured by FFSS, was compared in PBC patients and controls. The severity of fatigu e in the patients with PBC was correlated with other symptoms and with esta blished biochemical and histological markers of severity, Results: The FFSS questionnaire was acceptable to patients and had reasonab le intra-observer variation (coefficient of reproducibility 13% of mean val ue at 1 hour). The FFSS was more reproducible than a visual analogue scale. FFSSs varied over 4 weeks by up to 36%, Median FFSS's were 2.3 times highe r in PBC patients than controls (p<0.005), There were no associations betwe en FFSS and patient age, disease duration, or histological or biochemical m arkers of severity, Conclusions: The FFSS is a highly acceptable, internally consistent and rep roducible measure of fatigue se verity in PBC, We advocate its use in clini cal assessment of patients, in studies of the aetiology of fatigue in PBC a nd, most importantly, in therapeutic trials of symptomatic treatment.