Objectives: Fatigue is an important systemic symptom of rheumatoid arthritis (RA) but has rarely been evaluated consistently after initiation of treatment in RA patients. This study examined the effects of adalimumab (HUMIRA, Abbott Laboratories, Abbott Park, IL, USA), a fully human, anti-tumor necrosis factor (anti-TNF) monoclonal antibody, on reducing fatigue in patients with RA.
Methods: A total of 1526 patients with RA were enrolled in 3 randomized, placebo-controlled clinical trials of adalimumab versus placebo plus methotrexate (MTX) or placebo plus standard antirheumatic therapies. Fatigue was assessed with the Functional Assessment of Chronic Illness Therapy (FACIT) fatigue scale questionnaire (which has been validated in RA) at baseline, mid-study, and at the end of the study. Logistic regression models were constructed using baseline demographic variables to test for treatment effect. In addition, sensitivity analyses were performed to determine the robustness of the data.
Results: At baseline in the 3 trials, patients' fatigue ranged from 27.9-29.7, representing considerable fatigue on the FACIT fatigue scale. Fatigue was significantly and consistently reduced in adalimumab-treated patients in the 3 clinical trials. Relative to placebo plus MTX, the adalimumab 40-mg-every-other-week dosage group reported statistically significantly less fatigue at all time points post-baseline. Improvements between adalimumab and placebo ranged from 3-7 points across all 3 trials, with a 3-4-point change representing a minimum clinically important difference.
Conclusion: Adalimumab treatment was shown to significantly reduce fatigue in patients with moderate to severe RA. Changes in fatigue in all 3 trials were found to be clinically important.