Feld J, Chandran V, Haroon N, Inman R, Gladman D. Axial disease in psoriatic arthritis and ankylosing spondylitis: a critical comparison. Nat Rev Rheumatol. 2018;14:363–71.

Article  PubMed  Google Scholar 

Gladman DD. Axial disease in psoriatic arthritis. Curr Rheumatol Rep. 2007;9:455–60.

Article  PubMed  Google Scholar 

Gottlieb A, Korman NJ, Gordon KB, Feldman SR, Lebwohl M, Koo JY, et al. Guidelines of care for the management of psoriasis and psoriatic arthritis: Section 2. Psoriatic arthritis: overview and guidelines of care for treatment with an emphasis on the biologics. J Am Acad Dermatol. 2008;58:851–64.

Hanly JG, Russell ML, Gladman DD. Psoriatic spondyloarthropathy: a long-term prospective study. Ann Rheum Dis. 1988;47:386–93.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Baraliakos X, Coates LC, Braun J. The involvement of the spine in psoriatic arthritis. Clin Exp Rheumatol. 2015;33:S31–5.

PubMed  Google Scholar 

Gezer HH, Duruoz MT. The value of SPARCC sacroiliac MRI scoring in axial psoriatic arthritis and its association with other disease parameters. Int J Rheum Dis. 2022;25:433–9.

Article  PubMed  Google Scholar 

Mease PJ, Palmer JB, Liu M, Kavanaugh A, Pandurengan R, Ritchlin CT, et al. Influence of axial involvement on clinical characteristics of psoriatic arthritis: analysis from the Corrona Psoriatic Arthritis/Spondyloarthritis Registry. J Rheumatol. 2018;45:1389–96.

Article  PubMed  Google Scholar 

Jadon DR, Sengupta R, Nightingale A, Lindsay M, Korendowych E, Robinson G, et al. Axial Disease in Psoriatic Arthritis study: defining the clinical and radiographic phenotype of psoriatic spondyloarthritis. Ann Rheum Dis. 2017;76:701–7.

Article  PubMed  Google Scholar 

Gottlieb AB, Merola JF. Axial psoriatic arthritis: An update for dermatologists. J Am Acad Dermatol. 2021;84:92–101.

Article  PubMed  Google Scholar 

Eder L, Chandran V, Gladman DD. What have we learned about genetic susceptibility in psoriasis and psoriatic arthritis? Curr Opin Rheumatol. 2015;27:91–8.

Article  CAS  PubMed  Google Scholar 

Chandran V, Tolusso DC, Cook RJ, Gladman DD. Risk factors for axial inflammatory arthritis in patients with psoriatic arthritis. J Rheumatol. 2010;37:809–15.

Article  PubMed  Google Scholar 

Feld J, Ye JY, Chandran V, Inman RD, Haroon N, Cook R, et al. Is axial psoriatic arthritis distinct from ankylosing spondylitis with and without concomitant psoriasis? Rheumatology (Oxford). 2020;59:1340–6.

Article  PubMed  Google Scholar 

Garrett S, Jenkinson T, Kennedy LG, Whitelock H, Gaisford P, Calin A. A new approach to defining disease status in ankylosing spondylitis: the Bath Ankylosing Spondylitis Disease Activity Index. J Rheumatol. 1994;21:2286–91.

CAS  PubMed  Google Scholar 

Lukas C, Landewe R, Sieper J, Dougados M, Davis J, Braun J, et al. Development of an ASAS-endorsed disease activity score (ASDAS) in patients with ankylosing spondylitis. Ann Rheum Dis. 2009;68:18–24.

Article  CAS  PubMed  Google Scholar 

Veale DJ, Fearon U. The pathogenesis of psoriatic arthritis. Lancet. 2018;391:2273–84.

Article  CAS  PubMed  Google Scholar 

McInnes IB, Kavanaugh A, Gottlieb AB, Puig L, Rahman P, Ritchlin C, et al. Efficacy and safety of ustekinumab in patients with active psoriatic arthritis: 1 year results of the phase 3, multicentre, double-blind, placebo-controlled PSUMMIT 1 trial. Lancet. 2013;382:780–9.

Article  CAS  PubMed  Google Scholar 

Ritchlin C, Rahman P, Kavanaugh A, McInnes IB, Puig L, Li S, et al. Efficacy and safety of the anti-IL-12/23 p40 monoclonal antibody, ustekinumab, in patients with active psoriatic arthritis despite conventional non-biological and biological anti-tumour necrosis factor therapy: 6-month and 1-year results of the phase 3, multicentre, double-blind, placebo-controlled, randomised PSUMMIT 2 trial. Ann Rheum Dis. 2014;73:990–9.

Article  CAS  PubMed  Google Scholar 

Mease PJ, McInnes IB, Kirkham B, Kavanaugh A, Rahman P, van der Heijde D, et al. Secukinumab inhibition of interleukin-17A in patients with psoriatic arthritis. N Engl J Med. 2015;373:1329–39.

Article  CAS  PubMed  Google Scholar 

Deodhar A, Helliwell PS, Boehncke WH, Kollmeier AP, Hsia EC, Subramanian RA, et al. Guselkumab in patients with active psoriatic arthritis who were biologic-naive or had previously received TNFα inhibitor treatment (DISCOVER-1): a double-blind, randomised, placebo-controlled phase 3 trial. Lancet. 2020;395:1115–25.

Article  CAS  PubMed  Google Scholar 

Mease PJ, Rahman P, Gottlieb AB, Kollmeier AP, Hsia EC, Xu XL, et al. Guselkumab in biologic-naive patients with active psoriatic arthritis (DISCOVER-2): a double-blind, randomised, placebo-controlled phase 3 trial. Lancet. 2020;395:1126–36.

Article  CAS  PubMed  Google Scholar 

Baraliakos X, Gossec L, Pournara E, Jeka S, Mera-Varela A, D’Angelo S, et al. Secukinumab in patients with psoriatic arthritis and axial manifestations: results from the double-blind, randomised, phase 3 MAXIMISE trial. Ann Rheum Dis. 2021;80:582–90.

Article  CAS  PubMed  Google Scholar 

Kavanaugh A, Puig L, Gottlieb AB, Ritchlin C, You Y, Li S, et al. Efficacy and safety of ustekinumab in psoriatic arthritis patients with peripheral arthritis and physician-reported spondylitis: post-hoc analyses from two phase III, multicentre, double-blind, placebo-controlled studies (PSUMMIT-1/PSUMMIT-2). Ann Rheum Dis. 2016;75:1984–8.

Article  CAS  PubMed  Google Scholar 

Mease PJ, Helliwell PS, Gladman DD, Poddubnyy D, Baraliakos X, Chakravarty SD, et al. Efficacy of guselkumab on axial involvement in patients with active psoriatic arthritis and sacroiliitis: a post-hoc analysis of the phase 3 DISCOVER-1 and DISCOVER-2 studies. Lancet Rheumatol. 2021;3:E715–23.

Article  CAS  Google Scholar 

Eder L, Chandran V, Shen H, Cook RJ, Gladman DD. Is ASDAS better than BASDAI as a measure of disease activity in axial psoriatic arthritis? Ann Rheum Dis. 2010;69:2160–4.

Article  PubMed  Google Scholar 

Machado P, Landewe R, Lie E, Kvien TK, Braun J, Baker D, et al. Ankylosing Spondylitis Disease Activity Score (ASDAS): defining cut-off values for disease activity states and improvement scores. Ann Rheum Dis. 2011;70:47–53.

Article  PubMed  Google Scholar 

Machado PM, Landewe R, van der Heijde D, Assessment of SpondyloArthritis international S. Ankylosing Spondylitis Disease Activity Score (ASDAS): 2018 update of the nomenclature for disease activity states. Ann Rheum Dis. 2018;77:1539–40.

Article  PubMed  Google Scholar 

Marsh SGE, Albert ED, Bodmer WF, Bontrop RE, Dupont B, Erlich HA, et al. Nomenclature for factors of the HLA system, 2010. Tissue Antigens. 2010;75:291–455.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Benavent D, Capelusnik D, Ramiro S, Molto A, Lopez-Medina C, Dougados M, et al. Does gender influence outcome measures similarly in patients with spondyloarthritis? Results from the ASAS-perSpA study. RMD Open. 2022;8:e002514.

Kwok TSH, Sutton M, Pereira D, Cook RJ, Chandran V, Haroon N, et al. Isolated axial disease in psoriatic arthritis and ankylosing spondylitis with psoriasis. Ann Rheum Dis. 2022;81:1678–84.

Article  PubMed  Google Scholar 

Baeten D, Ostergaard M, Wei JC, Sieper J, Jarvinen P, Tam LS, et al. Risankizumab, an IL-23 inhibitor, for ankylosing spondylitis: results of a randomised, double-blind, placebo-controlled, proof-of-concept, dose-finding phase 2 study. Ann Rheum Dis. 2018;77:1295–302.

Article  CAS  PubMed  Google Scholar 

Deodhar A, Gensler LS, Sieper J, Clark M, Calderon C, Wang Y, et al. Three multicenter, randomized, double-blind, placebo-controlled studies evaluating the efficacy and safety of ustekinumab in axial spondyloarthritis. Arthritis Rheumatol. 2019;71:258–70.

Article  CAS  PubMed  Google Scholar 

Braun J, Landewe RBM. No efficacy of anti-IL-23 therapy for axial spondyloarthritis in randomised controlled trials but in post-hoc analyses of psoriatic arthritis-related “physician-reported spondylitis”? Ann Rheum Dis. 2022;81:466–8.

Article  CAS  PubMed  Google Scholar 

Fragoulis GE, Pappa M, Evangelatos G, Iliopoulos A, Sfikakis PP, Tektonidou MG. Axial psoriatic arthritis and ankylosing spondylitis: same or different? A real-world study with emphasis on comorbidities. Clin Exp Rheumatol. 2022;40:1267–72.

PubMed  Google Scholar 

Kavanaugh A, Baraliakos X, Gao S, Chen W, Sweet K, Chakravarty SD, et al. Genetic and molecular distinctions between axial psoriatic arthritis and radiographic axial spondyloarthritis: post hoc analyses from four phase 3 clinical trials. Adv Ther. 2023;40:2439–56.

McGonagle D, Watad A, Sharif K, Bridgewood C. Why inhibition of IL-23 lacked efficacy in ankylosing spondylitis. Front Immunol. 2021;12: 614255.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Rahman P, Inman RD, Gladman DD, Reeve JP, Peddle L, Maksymowych WP. Association of interleukin-23 receptor variants with ankylosing spondylitis. Arthritis Rheum. 2008;58:1020–5.

Article  CAS  PubMed  Google Scholar 

Vecellio M, Hake VX, Davidson C, Carena MC, Wordsworth BP, Selmi C. The IL-17/IL-23 axis and its genetic contribution to psoriatic arthritis. Front Immunol. 2021;11: 596086.

Article  PubMed  PubMed Central  Google Scholar 

Queiro R, Sarasqueta C, Belzunegui J, Gonzalez C, Figueroa M, Torre-Alonso JC. Psoriatic spondyloarthropathy: a comparative study between HLA-B27 positive and HLA-B27 negative disease. Semin Arthritis Rheum. 2002;31:413–8.

Article  PubMed  Google Scholar 

McInnes IB, Rahman P, Gottlieb AB, Hsia EC, Kollmeier AP, Xu XL, et al. Long-term efficacy and safety of guselkumab, a monoclonal antibody specific to the p19 subunit of interleukin-23, through two years: results from a phase III, randomized, double-blind, placebo-controlled study conducted in biologic-naive patients with active psoriatic arthritis. Arthritis Rheumatol. 2022;74:475–85.

Article  CAS  PubMed  PubMed Central