Serum irisin level in rheumatoid arthritis patients: Relationship to disease activity, subclinical atherosclerosis, and cardiovascular risk factors

Abstract

Aim of the workTo assess serum irisin level in rheumatoid arthritis (RA) patients, determine the relationship between irisin levels, disease activity and cardiovascular (CV) risk factors, and to evaluate its performance in predicting subclinical atherosclerosis and disease activity. Patients and methods60 RA patients and 30 controls were recruited for serological enzyme linked immunosorbant assay (ELISA) testing of irisin levels. Disease activity score (DAS28), health assessment questionnaire disability index (HAD-DI) and American college of rheumatology classification of functional status were assessed. Levels of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), glycated hemoglobin (HbA1c), insulin and lipid profile were measured. Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) was calculated. Carotid intimal medial thickness (C-IMT) was measured and echocardiography performed. ResultsSerum irisin levels were significantly lower in patients (9.8 ± 10.6 ng/ml) vs. controls (20.5 ± 13.8 ng; p < 0.001). Irisin levels inversely correlated significantly with C-IMT, body mass index (BMI), HOMA-IR, disease activity and disability. Patients with CV involvement showed significantly lower serum irisin level, increased disease activity and disability. Classifying patients based on cut-off values of DAS28 into low, moderate, and high disease activity, a significant difference in irisin levels was found, being lowest among highly active patients. Irisin performed as an excellent independent indicator of subclinical atherosclerosis (p < 0.001) and high disease activity (p < 0.001) in RA patients. ConclusionIn RA, decreased irisin were significantly associated with increased CV risk and performed better than traditional yardsticks in identifying disease activity. It may act as an independent indicator of subclinical atherosclerosis within RA patients.