PURPOSE: Fatigue is one of the most common and disabling symptoms experienced by people with inflammatory bowel disease
however, interventions to treat fatigue are limited. The purpose of this systematic review is to examine the relationship between sleep deficiency and fatigue in adults with inflammatory bowel disease and to describe the demographic and clinical factors associated with fatigue to inform future intervention work. METHODS: We conducted a systematic review and reported the results using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The search was conducted using MEDLINE, EMBASE, PsycINFO, CINAHL, and CENTRAL on 3/7/24. We included studies with adults (≥18 years of age) who had a diagnosis of inflammatory bowel disease (Crohn's disease, ulcerative colitis, or indeterminate colitis) and measured fatigue and sleep using a validated self-report questionnaire or objective measurement. RESULTS: Twenty-two studies met inclusion criteria for a total sample of 16 927, of whom 58.7% (n = 9937) had Crohn's disease, and 66.3% (n = 11 226) were female. 56.1% of the participants experienced fatigue and 66.3% experienced sleep deficiency. Sleep quality and insomnia were consistently associated with fatigue. Baseline poor sleep quality was associated with persistent and worsening fatigue over 12 to 24 months. Clinical but not objective assessment of disease activity, anxiety, depression, female gender/sex, and younger age were also associated with more severe fatigue. CONCLUSIONS: Sleep quality and insomnia represent important modifiable contributors to fatigue. Future research should explore whether sleep interventions can improve fatigue in this population.