Objectives
Fatigue is a disabling symptom in people with Rheumatoid Arthritis (RA). This study aims to describe the prevalence, risk factors and the longitudinal course of fatigue in early RA.
Methods
Demographic, clinical, quality of life (QoL), comorbidities and laboratory data were from the Early Rheumatoid Arthritis Network (ERAN), a UK multicentre inception cohort of people with RA.
Fatigue was measured using the Vitality subscale of SF36 where higher values represented better QoL. Baseline prevalences of fatigue classifications were age and sex standardised. Linear regression, hierarchical growth curve modelling and group-based trajectory modelling (GBTM) were utilized.
Results
At baseline (n = 1236, 67% female, mean age 57), mean Vitality was 41 (SD ± 11), disease duration 11 months (IQR : 7–18). Age and sex standardized prevalence rates of fatigue and severe fatigue were 44% (CI: 39–50) and 19% (CI: 15–23) respectively.
Fatigue changed little over 3 years and 5 measurement occasions, ß=-0.13 (-0.23 to -0.02). GBTM identified 2 sub-groups, which we named ‘Fatigue’ (53%) and ‘No-fatigue’ (47%) groups. Female sex, worse pain, mental health, and functional ability were associated with greater fatigue and predicted ‘Fatigue’ group membership (AUROC = 0.81). Objective measures of inflammation—swollen joint count (SJC) and erythrocyte sedimentation rate (ESR) were not significantly associated with fatigue.
Conclusions
Fatigue is prevalent and persistent in early RA. Diverse characteristics indicative of central mechanisms are associated with persistent fatigue. Management of fatigue might require interventions targeted at central mechanisms in addition to inflammatory disease modification. People who require such interventions might be identified at presentation with early RA.