The relationship between sleep problems and fatigue in chronic fatigue syndrome (CFS)

Abstract

Background: Sleep symptoms are common in chronic fatigue syndrome (CFS). We aimed to describe sleep symptoms and their relationship to fatigue, and to determine whether improvements in sleep mediated treatment effects on fatigue. Methods: 296 adult participants in a randomized controlled trial which compared pragmatic rehabilitation with treatment as usual for CFS completed questionnaire measures of sleep symptoms and fatigue at baseline, end of treatment (20 weeks) and 70 weeks follow up. Findings: At baseline, 274 (93%) patients scored within the clinical range for at least one sleep symptom, with 260 (88%) reporting waking unrefreshed. Sleep symptoms and fatigue were weakly correlated (r=.192). Regression analyses, controlling for relevant baseline variables and treatment allocation, showed that the beneficial effect of pragmatic rehabilitation on fatigue at follow up was partially mediated (29%) by improvements in sleep at the end of treatment (effect size -0.94, SE= 0.44, P=.034). Discussion: Improvements in sleep may be one mechanism by which pragmatic rehabilitation improves fatigue. Future work will test multiple mediation models including sleep and previously described cognitive mediators of pragmatic rehabilitation.