To assess predictive factors of improvement in related fatigue in rheumatoid arthritis (RA) patients newly receiving biologic therapy, and specifically the influence of the improvement of the quality of sleep.
We conducted a multicentre prospective study in RA patients requiring initiation or change of biologic therapy. The improvement in fatigue, sleep disorders and depression was assessed respectively by the FACIT fatigue scale, Spiegel scale and Beck Depression Inventory at inclusion (M0) and 3 months (M3) after the beginning of treatment. Potential confounders were assessed and adjusted for. The association between evolution of fatigue and other characteristics were evaluated by univariate (χ2) then multivariate (logistic regression) analyses.
We followed-up 99 patients. FACIT scores at M0 revealed frequently reported fatigue: 89%, high prevalence of sleep disorders: 95% and depression: 67%. Improvement of fatigue, sleep quality and depression was observed in 58.6%, 26.3% and 34.3% of cases, respectively. Significant factors associated with an improvement in fatigue at M3 were an elevated sedimentation rate at M0 (OR=5.7[2.0-16.0], p=0.001) and a favourable EULAR response at M3 (OR=4.8[1.6-14.8], p=0.006). Furthermore, a number of swollen joints > 5 at baseline (OR=0.3 [0.1-0.8]) and the use of psychotropic drugs (OR=0.2[0.04-0.9]) were predictive of an absence of improvement in fatigue. No significant association with the improvement in sleep disorders could be demonstrated.
Fatigue in RA is improved by effective treatment, via decreasing disease activity. Improvement of sleep disorders is more likely a surrogate of therapeutic efficiency rather than an independent outcome.