Predictors of Fatigue in Rheumatoid Arthritis Patients in Remission or in a Low Disease Activity State.

Objective: Fatigue is a frequently occurring symptom in patients with rheumatoid arthritis (RA). Our aims were to assess the level of reported fatigue in RA patients who had achieved remission or low disease activity after 6 months of treatment with disease-modifying antirheumatic drugs (DMARDs), and to explore associations between fatigue and demographics, disease activity, and other patient-reported outcomes in this patient group.

Methods: A total of 2,193 RA patients (ages ≥18 years) starting either methotrexate (MTX) monotherapy or a tumor necrosis factor inhibitor in combination with MTX were retrieved from the Norwegian Disease-Modifying Antirheumatic Drugs Register (NOR-DMARD). At the 6-month followup, 699 patients (31.9%) were in remission or in a low disease activity state. Bivariate and multivariate linear regression analyses were conducted, with the fatigue visual analog scale (VAS) at 6 months as the dependent variable. Age, sex, disease duration, treatment group, erythrocyte sedimentation rate (ESR), the swollen and tender joint count in 28 joints, the pain VAS score, and disability at baseline and at 6 months were tested as predictors of fatigue at 6 months.

Results: At 6 months, the median (25th, 75th percentile) level of fatigue was 20.0 mm (6.0, 43.0), and a fatigue VAS score of ≥40 mm was reported by 27.9% of patients. In the multivariate analysis, lower ESR and higher pain at baseline were statistically significant predictors of higher levels of fatigue (P < 0.001). In the multivariate cross-sectional analysis at 6 months, younger age and greater pain were significantly associated with higher levels of fatigue (P < 0.001).

Conclusion: Pain levels at baseline and at 6 months were associated with a higher level of fatigue. Patients in remission or in a low disease activity state may need nonpharmacologic interventions to manage their pain and fatigue.