Understanding Predictors of Fatigue Over Time in Persons With Inflammatory Bowel Disease: The Importance of Depressive and Anxiety Symptoms

INTRODUCTION: Fatigue is a complex and frequent symptom in persons with inflammatory bowel disease (IBD), with detrimental impact. We aimed to determine predictors of fatigue over time. METHODS: Two hundred forty-seven adults with IBD participated in a prospective study conducted in Manitoba, Canada, providing data at baseline and annually for 3 years. Participants reported fatigue impact (Daily Fatigue Impact Scale [DFIS]), depression and anxiety symptoms (Hospital Anxiety and Depression Scale [HADS]), and pain (Pain Effects Scale [PES]). Physician-diagnosed comorbidities, IBD characteristics, and physical and cognitive functioning were also assessed. We tested factors associated with fatigue using multivariable generalized linear models that estimated within-person and between-person effects. RESULTS: Most participants were women (63.2%), White (85.4%), and had Crohn's disease (62%). At baseline, 27.9% reported moderate-severe fatigue impact, 16.7% had clinically elevated anxiety (HADS-A ≥11), and 6.5% had clinically elevated depression (HADS-D ≥11). Overall fatigue burden was stable over time, although approximately half the participants showed improved or worsening fatigue impact between annual visits during the study. On multivariable analysis, participants with a one-point higher HADS-D score had, on average, a 0.63-point higher DFIS score, whereas participants with a one-point higher PES score had a 0.78-point higher DFIS score. Within individuals, a one-point increase in HADS-D scores was associated with 0.61-point higher DFIS scores, in HADS-A scores with 0.23-point higher DFIS scores, and in PES scores with 0.38-point higher DFIS scores. No other variables predicted fatigue. DISCUSSION: Anxiety, depression, and pain predicted fatigue impact over time in IBD, suggesting that targeting psychological factors and pain for intervention may lessen fatigue burden.