CRP and Sacroiliac arthritis: At T0, non-naïve (versus naïve) patients were older and more frequently HLA-B27-positive, had a longer duration of axial symptoms, higher signs of active or radiographic sacroiliitis, had a greater prevalence of peripheral arthritis, enthesitis, dactylitis, and psoriasis, and worse functional status (HAQ-S and BASFI) and disease activity indices (higher CRP and BASDAI values) (Table 1).