Increased serum levels of MIC1/GDF15 correlated with bone erosion in spondyloarthritis A pilot study

Introduction: To assess the association between growth differentiation factor-15 (GDF15) and radiographic features including bone marrow edema and bone erosion in Spondyloarthritis (SpA). Methods: Patients with SpA (n=120) receiving treatment in the Guangdong General Hospital, China, between August 2012 and December 2016 were retrospectively included. Serum of patients and healthy controls (n=30) were collected and GDF15 levels were measured using ELISA. Inflammation was assessed by C-reactive protein (CRP). and magnetic resonance imaging (MRI) of the sacroiliac joint using Spondyloarthritis Research Consortium of Canada score and a method of dichotomy to assess fat metaplasia, bone erosion, and ankylosis. Radiographs of the pelvis were scored using the modified New York (mNY) score. Results: Serum GDF15 levels were higher in SpA patients compared to controls (503.52 +/- 222.92 vs. 190.86 +/- 104.18 pg/mL, P<.0001). Patients who suffered from bone erosion on MRI had higher levels of GDF15 (525.72 [186.33, 801.62]vs. 428.06 [255.15, 670.98] pg/mL, P=.0375). There was a positive correlation between serum GDF15 and CRP (r=0.5442, P<.0001). Moreover, GDF15 levels were related to CRP levels (r=0.5658, P<.0001) in those X-ray scores were III, according to 1984mNY criteria. Receiver operating characteristic (ROC) analysis showed that GDF15 levels above 501.98pg/mL could predict presence of bone erosion on MRI. Conclusion: The present study suggested that serum GDF15 levels are higher in SpA patients than in healthy controls. The GDF15 level was correlated with CRP and may be a surrogate biomarker in bone erosion.