GDF-15 (growth differentiation factor) levels in rheumatoid arthritis: Relationship between clinic parameters and radiologic score

Objectives: Growth differentiation factor (GDF)-15 was originally identified as a factor secreted by activated macrophages, and plays an important role in cell growth and differentiation. GDF-15 plays an important role in cell growth, signal transduction, and apoptosis regulation. The aim of this study was to evaluate serum GDF-15 levels and their relationship with disease-related characteristics in patients with Rheumatoid Arthritis (RA). Materials and methods: Forty-six patients diagnosed with RA and 36 demographically matched healthy control subjects participated in the study. GDF-15 levels were measured in blood samples from patients and controls. Disease activity score-28 (DAS28) was used to evaluate the disease activity of RA. The quality of life was evaluated using the disease-specific rheumatoid arthritis quality of life (RAQoL) scale. The health assessment questionnaire (HAQ) was used for the evaluation of the functional status. The degree of joint damage were assessed according to Larsen's method. Atherosclerosis was assesed by a cardiologist with the help of echocardiography according to Carotid intima media thicness (CIMT) method; and also vascular stiffness was assesed by using flow mediated dilatation (FMD) method. Results: The serum GDF-15 levels were significantly higher in RA patients when compared to the control subjects (p>0.05). RA patients were divided into two groups according to the disease activity; while 26 subjects (57%) were in active group, 20 patients were in nonactive group (43%). Serum GDF-15 levels were significantly higher in the group that was considered as active disease. According to the Pearson carrelation, serum GDF-15 levels were positively correlated with, erythrocyte sedimentation rate (ESR) level, morning stiffness, DAS28 score, tender joint count and CIMT (p<0.05). Conclusion: GDF-15 may play a role in the progression and pathway of disease activity, joint involvement and atherosclerosis in patients with Rheumatoid arthritis. Keywords: Rheumatoid arthritis, GDF-15, disease activity, morning stiffness, atherosclerosis