Multivariate analysis revealed a significant positive association of DKK-1 serum level and female gender (p = 0.03), CRP level (p = 0.006), SOST serum level (p = 0.002) and the presence of sacroiliitis on radiography (p = 0.05) (Table 3). This evidence concerns the gene DKK1 and Sacroiliac arthritis.