Background Fatigue is a frequent symptom among patients with psoriatic arthritis (PsA). Occurrence in literature is given in up to 45% of patients  and changes in fatigue were shown to reflect changes in disease activity  and improve with treatment with adalimumab 
Objectives To assess the effect of one year biologic therapy on fatigue in PsA patients and correlate it with other parameters of the disease like laboratory and clinical activity, function and the quality of life.
Methods 265 pats. from the Czech register of patients with PsA (ATTRA), who had been treated with first line biological therapy for a minimum of 1 year were analyzed. Following parameters were assessed at the start of biological therapy and 12 months after. Fatigue was assessed using the ninth item from SF-36, question “did you feel tired during past 4 weeks”? Laboratory activity according to ESR and CRP, clinical activity was assessed by No. of tender (out of 68) and swollen (out of 66) joints and by phycian's PsA assessment (VAS100mm), function by HAQ and quality of life by EuroQOL and further items of SF-36 (physical functioning, role-physical, bodily pain, general health, vitality, social functioning, role-emotional and mental health). Improvement, disease activity, function and quality of life after 12 month of biological therapy was assessed by counts (percentages) and median (interquartile range) when describing categorical and continuous variables respectively. Significance of improvement after 12 months and significance of association between fatigue improvement and improvement in other parameters of disease was assessed using p-value of Wilcoxon Signed Ranks Test and Kruskal-Wallis H Test, respectively.
Results After 12 months there is a significant improvement of fatigue, as well as parameters of activity, function and quality of life (p<0,001 for all). As to the correlation of the change in fatigue with the change of parameters of activity, function and the quality of life, the differences between pats. in whom the fatigue improved were more strong as compared with pats. in whom fatigue worsened, or remained stable. The improvement of fatigue correlates most strongly with those parameters assessed by pats., less (but still significantly) with objective parameters (tender joints-p=0,003 and swollen joints- p=0,024) and surprisingly not with ESR and CRP.
Conclusions One year biological therapy of PsA leads to significant improvement not only of clinical parameters of the disease, but also to significant improvement of fatigue. The improvement of fatigue strongly correlates with the improvement of function and quality of life, less (but still significantly) with clinical parameters and surprisingly not with humoral activity.
Schentag CT, Beaton M, Rahman P et al. Fatigue in psoriatic arthritis (PsA). J Rheumatol 1999;26:1627
Schentag C, Gladman DD. Changes in fatigue in psoriatic arthritis, disease activity or fibromyalgia. Arthritis Rheum 2002;46(Suppl 9):S424
Mease PJ, Gladman DD, RitchlinCT, et al. Adalimumab for the treatment of patients with moderately to severely active psoriatic arthritis. Arthritis Rheum 2005;52:3297-89
Acknowledgements Supported by the Research program of the Ministry of health of Czech Republic: IGA MZ CR: No. 000 000 23728.
Disclosure of Interest None declared