Association between serum dickkopf-1 levels and disease duration in axial spondyloarthritis.

Background: Axial spondyloarthritis (axSpA) is characterized by new bone formation. The complex systems underlying this process involve Wnt-signaling pathway. It has been observed that serum levels of dickkopf-1 (DKK-1), an important inhibitor of Wnt-signaling, are decreased in patients with axSpA. However, these data are from studies including only patients with long-standing disease. The aim of this study is to investigate if symptom duration influences on serum DKK-1 levels in patients with axSpA. Material and methods: A cross-sectional study including consecutive patients with axSpA (ASAS criteria) naive for anti-TNF therapy. Collected data included demographic and disease characteristics, time since first symptom onset, assessment of disease activity and function, and determination of DKK-1 serum levels. Patients were classified as early axSpA ( symptom duration <= 5 years) and established axSpA (>5 years). Linear regression models were employed to investigate the variables related to DKK-1 serum levels. Results: In total, 90 patients were included. Sixty-eight patients had early axSpA and 22 had established disease. Serum levels of DKK-1 were significantly higher in patients with early axSpA compared with established axSpA (22.1 +/- 12.6 vs 16.4 +/- 10.7 pM; p = 0.04). Among all tested variables, only symptom duration was significantly and inversely correlated with DKK-1 serum levels (beta: -0.041; p = 0.01). Conclusion: Serum DKK-1 levels in axSpA depend on disease duration. As disease duration increases, DKK-1 serum levels decrease. Based on this, an intensive treatment at early stages of the disease could have a better outcome on inhibiting/slowing radiographic progression in patients with axSpA. (C) 2016 Elsevier Espana, S.L.U. and Sociedad Espanola de Reumatologia y Colegio Mexicano de Reumatologia. All rights reserved.