Sleep disorders are significant problems in patients with rheumatoid arthritis (RA) and are associated with poor quality of life. Irisin is myokine which may have anti-inflammatory and energy regulatory roles. This study assessed the association of serum irisin levels with the quality of sleep and disease activity in RA patients.
In sum, 58 RA patients and 30 matched healthy controls were included. Disease activity score in 28 joints (DAS28-ESR) and the patients' global score were calculated. RA patients were grouped according to the Pittsburgh Sleep Quality Index score (PSQI) into good-sleepers (group 1) defined as a PQSI score≤5 and poor sleepers (group 2) with a PSQI > 5. Serum irisin levels were measured for both patients and controls by commercially available enzyme-linked immunosorbent assay kits.
Poor sleep quality was found in 26 (45%) of the RA patients. Irisin levels were significantly lower in RA patients with poor sleep compared to those with good sleep and healthy controls (p < 0.001). Serum irisin levels correlated inversely with disease duration, morning stiffness duration, DAS28-ESR, global score, and total PSQI score (r = -0.722 to -0.263 & p values≤0.001-0.04) indicating a possible anti-inflammatory role of irisin in RA patients. The analysis employed Student's t-test, ANOVA, and Pearson correlation.
Irisin levels were decreased in RA patients with poor sleep quality compared to RA patients with good sleep quality and healthy controls, indicating a possible association of decreased serum irisin with sleep impairment in RA patients.