Predictors of fatigue over 1 year among people with rheumatoid arthritis.

Fatigue is a systemic feeling of exhaustion that is a common symptom of many chronic illnesses, including the autoimmune inflammatory disease rheumatoid arthritis (RA). We examined predictors of levels of fatigue among people with RA using Leventhal's Common-Sense Model (CSM), which states that cognitive representations of an illness spur (or halt) people's efforts to cope and thereby influence outcomes of the illness. Our use of the CSM was designed in the light of evidence in the literature specific to fatigue in RA. Current fatigue was reported on a 100 mm visual analogue scale (with anchors "No fatigue" and "Unbearable fatigue") by 114 people (73.7% women) with RA at baseline and 1 year later. Baseline employment status, pain, impact of disability, sleep disruption frequency, depressed mood, perceptions of consequences, arthritis self-efficacy and attempts to cope by praying/hoping were also self-reported. Duration of RA and a haematological measure of systemic inflammation (erythrocyte sedimentation rate; ESR) were obtained from hospital records. Unexpectedly, RA duration did not predict fatigue after 1 year, although lower baseline inflammation did (controlling for baseline fatigue and other disease impact variables). This may be due to sampling flares of RA at baseline. Baseline perceptions that RA has severe consequences and is uncontrollable also predicted greater fatigue after 1 year but this relationship was not mediated by praying/hoping. Targeted psychological care to modify perceptions of severe consequences may therefore improve later fatigue for people with RA even when the condition is longstanding, but the mechanisms of any benefit require further investigation.