Serum Interleukin-6 In Primary Fibromyalgia Syndrome Patients: Impact On Disease Burden, Severity, Quality Of Life And Sleep

Aim of the work: To assess serum interleukin-6 (IL-6) level in primary fibromyalgia syndrome (FMS) patients and to study its relation to disease burden parameters Patients and methods: Forty primary FMS patients and 40 age and sex matched controls were studied. Patients answered multiple questionnaires. Fatigue was assessed by multidimensional fatigue inventory (MFI-20), pain severity by visual analogue scale (VAS-pain) and sleep quality by sleep quality numerical rating scale (NRS). The 36-Item Short Form (SF-36) was used to assess quality of life and fibromyalgia Impact Questionnaire (FIQ) was used to evaluate patient status, progress and outcomes. Results: The patients mean age was 36.5 +/- 7.1 years and disease duration 5.3 +/- 2.95 years and they were 38 females and 2 males. The mean serum IL-6 level was significantly higher in patients (134.9 +/- 67.3 pg/ ml) than control (41.1 +/- 8.5 pg/ml)(p = 0.001). The mean VAS-pain was 6.2 +/- 1.3 (4-8), FIQ was 58 +/- 6.1 (50-70), SF-36 47 +/- 10.2 (30-60), MFI20 was 76.5 +/- 10.6 (60-95) and sleep quality NRS was 6.9 +/- 1.2 (5- 9). The values of the studied parameters and scores were significantly different from the control 1.4 +/- 0.5; 14.4 +/- 6.5; 93.9 +/- 3.5 10 +/- 5.2 and 0.9 +/- 0.8 respectively; p = 0.001 for all). There was a significant corre-lation between serum IL-6 levels and VAS-pain (r = 0.72, p = 0.001), FIQ (r = 0.58, p = 0.001), SF-36 (r = 0.78, p = 0.001), MFI-20 (r = 0.74, p = 0.001) and sleep NRS (r = 0.78,p = 0.001). On regression, IL-6 level had a greater impact on sleep NRS (p = 0.001), SF-36 (p = 0.005) and MFI20 (p = 0.01). Conclusions: Serum IL-6 level is high in primary FMS patients. Also, serum IL-6 is significantly related to the parameters of fatigue, functional status, sleep quality and pain. (c) 2021 THE AUTHORS. Publishing services by ELSEVIER B.V. on behalf of The Egyptian Society of Rheu-matic Diseases. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).