Multivariate analysis showed that peripheral arthritis was independently associated with older age (≥ 33 years old, which corresponds to the median age of the DESIR population) [OR 1.60 (95%CI 1.12–2.27)], non-smoking [OR 1.58 (95%CI 1.10–2.27)], HLAB-27 negative [OR 1.47 (95%CI 1.04–2.08)], abnormal CRP values at baseline (≥ 6 mg/dl) [OR 1.99 (95%CI 1.35–2.92)], no history of uveitis [OR 2.03 (95%CI 1.07–3.84)], pervious history of dactylitis [OR 8.50 (95%CI 4.96–14.6)] and previous history of any enthesitis [OR 2.00 (95%CI 1.41–2.84)]. This evidence concerns the gene CRP and enthesitis.