CRP and psoriasis: In the multivariate analysis, men (p < 0.001), younger age (p < 0.001), disease duration >3 years (p < 0.001), family history (p < 0.001), uveitis (p < 0.001), higher ASDAS-CRP (p < 0.001), and on biologic treatment (p < 0.001) were the main variables that are independently related to HLA-B27 presence, whereas diagnosis delay time > 36 months (p < 0.001), and psoriasis (p < 0.001) were independently related to HLA-B27 absence (Table 2).