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 the serum GDF-15 levels and their relationship with disease-related characteristics in patients with rheumatoid arthritis (RA).
Forty-six patients diagnosed with RA and 36 demographically matched healthy control subjects participated in this study. GDF-15 levels were measured in blood samples from patients and controls. The 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 to evaluate the functional status. The degree of joint damage was assessed according to Larsen's method. Atherosclerosis was assessed by a cardiologist with the help of echocardiography according to the carotid intima media thickness (CIMT) method; vascular stiffness was assessed by using the flow mediated dilatation (FMD) method.
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 the active group, 20 patients were in the non-active group (43%). Serum GDF-15 levels were significantly higher in the group that was considered to have an active disease. According to Pearson's correlation, serum GDF-15 levels were positively correlated with erythrocyte sedimentation rate (ESR) levels, morning stiffness, DAS28 score, tender joint count, and CIMT (p<0.05).
GDF-15 may play a role in the pathway of disease activity, joint involvement, and atherosclerosis in patients with rheumatoid arthritis.