Background Fatigue is a reliable and sensitive measure to change in rheumatoid arthritis (RA) whose contribution to disease activity seems to be directly or indirectly related with other symptoms of RA. The hypothalamic-pituitary adrenal (HPA)-axis IL-6 has been proposed as common triggering mechanism that could be target of tocilizumab (TCZ) action.
Objectives To evaluate the correlation of fatigue change with evolution of related factors as serum Hb levels, swollen joint count (SJC), morning stiffness, pain, sleepiness and depression and the following personal aspects: marital status, children living at home, employment status, important events in life, physical activity, hours of sleep at night and care for dependents
Methods A 24-week prospective, observational and multicenter study in patients with moderate to severe RA, non-responders or intolerants to DMARDs or TNF-inhibitors who initiated treatment with TCZ. Data were collected at the time of TCZ-beginning (baseline visit) and at 2 routine follow-up visits closest to the weeks 12 and 24 timepoints from baseline. Multiple regression analysis was made to determine the variance of fatigue outcomes relative to associated factors.
Results Of 122 patients included, 120 were evaluable (87% female) with a mean age of 52.2±12.6 years and a mean disease duration of 9.1±7.8 years. Mean baseline clinical measures included: Hb (g/dL), 12.4±1.4; CRP (mg/L), 12.5±16.9; DAS28 score, 5.6±1.0; TJC, 8.6±6.3; SJC, 5.9±4.2; patient's global assessment (visual analogue scale, VAS), 6.9±2.1; physician's global assessment (VAS), 6.1±2.0; pain VAS (cm), 6.7±2.3; morning stiffness duration (hours), 1.3±2.4; FACIT_F fatigue outcome, 23.7±11.1; Beck depression score, 18.5±13.0; Epworth sleepiness score, 6.1±4.5. Mean DAS28 decreased 2.7±1.4 points after 24 weeks and a good EULAR response was achieved by 61% of patients. Significant mean improvements at both weeks 12 and 24 from baseline were seen in fatigue outcomes and related factors (table). Multiple regression analysis shown that the independent variables sleepiness and depression were significantly associated with change in fatigue both in week 12 and 24 [week 12, (sleepiness: B=0.7; p<0.001; depression: B=0.45; p<0.001) and week 24, (sleepiness: B=0.9; p<0.001; depression: B=0.45; p<0.001)], and explained 35% of the variance (R2) in fatigue observed during the study
Conclusions Tocilizumab reduces the concentration of acute-phase reactants and improves Hb levels, which can lead to a decrease in fatigue experienced by patients with RA. Indirectly, this would result in subjective improvements in patient-reported outcomes. Change scores for sleepiness and depression are the only significant variables for fatigue reductions.
Disclosure of Interest None declared