[Irisin as a new marker for the early diagnosis of low-traumatic fractures in rheumatoid arthritis.]

The aim of this study was to study the relationship between serum irisin level and the presence of low-traumatic bone fractures in rheumatoid arthritis (RA) patients. We examined 170 people including 110 RA patients and 60 healthy individuals as comparison group. The serum irisin level was determined with solid-phase enzyme-linked immunosorbent assay using ELISA Irisin test system (BioVendor, cat. No. RAG018R). The average level of irisin in the group of healthy individuals was 20.49 ± 4.82 μg/ml (μ±σ). The level of normal values, defined as M ± 2σ, was 10.85-30.13 μg/ml. Decreased irisin level was detected in 41 of 110 patients with RA diagnosis (37% of cases). This group of patients had higher RA activity degree (DAS28), extra-articular manifestations, disease duration from 5 to 10 years, greater class of functional joint's failure, lower level of 25 (OH) -vitamin D. There was also a reliable relationship between serum irisin level and presence of low-fracture bone fractures in the anamnesis.