Elevated serum level of the vascular endothelial growth factor predicts radiographic spinal progression in patients with axial spondyloarthritis

Objective To investigate the role of serum vascular endothelial growth factor (VEGF) as a predictor of radiographic spinal progression in patients with axial spondyloarthritis (axSpA). Methods Altogether, 172 patients with definite axSpA (95 with ankylosing spondylitis and 77 with non-radiographic axSpA) were included in this study. Spinal radiographs obtained at baseline and after 2 years of follow-up were scored independently by two trained readers in a concealed and randomly selected order according to the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) scoring system and for the presence of syndesmophytes. Radiographic spinal progression after 2 years was defined as (1) mSASSS worsening by ≥2 units, and (2) new syndesmophyte formation or formation of a bridging syndesmophyte from two single syndesmophytes. Serum VEGF levels were detected at baseline. Results Mean baseline VEGF values were significantly higher in patients with mSASSS worsening by ≥2 units after 2 years (n=22) than in those without progression (562±357 vs 402±309 pg/mL, respectively, p=0.027) and in patients with syndesmophyte formation (n=18) again as compared with those without new bone formation (579±386 vs 404±307 pg/mL, respectively, p=0.041). VEGF as a predictor of radiographic spinal progression performed especially well in patients who were already at high risk for such a progression due to the presence of syndesmophytes at baseline (n=48). In these patients, a VEGF serum level of >600 pg/mL had a sensitivity of 53%, a specificity of 97% and an OR=36.6 (95% CI 3.9 to 341.5) as a predictor of mSASSS worsening by ≥2 units. For syndesmophyte formation, elevated VEGF demonstrated a sensitivity of 47%, a specificity of 94% and an OR=13.6 (95% CI 2.4 to 78.3). Conclusions An elevated serum level of VEGF (>600 pg/mL) is highly specific as a predictor of radiographic spinal progression in patients with axSpA, especially in patients who are at high risk for further progression due to the presence of syndesmophytes.