Predictors of fatigue in rheumatoid arthritis.

People with RA commonly experience fatigue. Fatigue is a key contributor to increased clinical care costs, primary care consultations and employment loss. Despite this, our understanding of the prognostic of factors of poor fatigue outcomes is lacking and fatigue is poorly managed. Examining longitudinal predictors of fatigue can identify both individuals 'at risk' of poor prognosis, and candidate mechanisms that are worthy of greater inspection. This review discusses the factors most commonly investigated as being implicated in the prognosis of RA fatigue. The available data appears to implicate generic factors such as pain, mental health, disability and sleep as consistent predictors of fatigue outcome, while the role of disease activity and inflammation seems less clear. However, the existing data are not without methodological limitations and there have been no specific studies primarily designed to investigate the inflammatory biomarkers of fatigue. Future studies are required to more comprehensively and robustly determine the mechanisms of fatigue.