Conclusion
Reductions in proinflammatory cytokines after CBT compared with a waiting-list control group confirm the potential value of these biomarkers as surrogate outcome measures in FM.
Methods
A controlled, single-blind, parallel clinical trial was performed with 21 FM patients in each group. Sixteen FM patients in the intervention group (CBT) and 17 FM patients in the control group (waiting-list) completed the study. For the intervention group, traditional face-to-face CBT was performed for groups of 10 and 11 patients in 20 sessions. Fibromyalgia Impact Questionnaire (FIQ), widespread pain index (WPI), circulating IL-6, IL-8, and TNF-α level were evaluated before and after the intervention using enzyme-linked immunosorbent assay. Intention-to-treat analysis was performed as the primary analysis.
Results
The average changes of factors examined were as follows: FIQ score -0.61 ± 5.5 in the waiting-list group and 10.2 ± 14.9 in the CBT group (p = 0.012); WPI -0.33 ± 1.1 in the waiting-list group and 2.4 ± 3.1 in the CBT group (p = 0.002); serum IL-6 level -0.05 ± 0.86 pg/ml in the waiting-list group and 1.5 ± 2.4 pg/ml in the CBT group (p = 0.002); serum IL-8 level - 0.55 ± 0.2.5 pg/ml in the waiting-list group and 5 ± 5.9 pg/ml in the CBT group (p = 0.002); serum TNF-α level 0.67 ± 1.8 pg/ml in the waiting-list group and 0.7 ± 1.6 pg/ml in the CBT group (p = 0.89).