• 1
    Scarpa R, Oriente P, Pucino A, Torella M, Vignone L, Riccio A, et al. Psoriatic arthritis in psoriatic patients. Br J Rheumatol 1984; 23: 24650.
  • 2
    Alenius GM, Stenberg B, Stenlund H, Lundblad M, Dahlqvist SR. Inflammatory joint manifestations are prevalent in psoriasis: prevalence study of joint and axial involvement in psoriatic patients, and evaluation of a psoriatic and arthritis questionnaire. J Rheumatol 2002; 29: 257782.
  • 3
    Saraux A, Guillemin F, Guggenbuhl P, Roux CH, Fardellone P, Le Bihan E, et al. Prevalence of spondyloarthropathies in France: 2001. Ann Rheum Dis 2005; 64: 14315.
  • 4
    Madland TM, Apalset EM, Johannessen AE, Rossebo B, Brun JG. Prevalence, disease manifestations, and treatment of psoriatic arthritis in Western Norway. J Rheumatol 2005; 32: 191822.
  • 5
    Narvaez J, Narvaez JA, Nolla JM, Valverde J. Comparative study of MR imaging findings in wrist and hands in early psoriatic arthritis and rheumatoid arthritis [abstract]. Arthritis Rheum 2007; 56 Suppl: S652.
  • 6
    Sokoll KB, Helliwell PS. Comparison of disability and quality of life in rheumatoid and psoriatic arthritis. J Rheumatol 2001; 28: 18426.
  • 7
    Husted JA, Gladman DD, Farewell VT, Cook RJ. Health-related quality of life of patients with psoriatic arthritis: a comparison with patients with rheumatoid arthritis. Arthritis Care Res 2001; 45: 1518.
  • 8
    Zink A, Thiele K, Huscher D, Listing J, Sieper J, Krause A, et al. Healthcare and burden of disease in psoriatic arthritis: a comparison with rheumatoid arthritis and ankylosing spondylitis. J Rheumatol 2006; 33: 8690.
  • 9
    European Medicines Agency. Leflunomide summary of product characteristics. 2010. URL:
  • 10
    Kaltwasser JP, Nash P, Gladman D, Rosen CF, Behrens F, Jones P, et al, for the Treatment of Psoriatic Arthritis Study Group. Efficacy and safety of leflunomide in the treatment of psoriatic arthritis and psoriasis: a multinational, double-blind, randomized, placebo-controlled clinical trial. Arthritis Rheum 2004; 50: 193950.
  • 11
    Nash P, Thaci D, Behrens F, Falk F, Kaltwasser JP. Leflunomide improves psoriasis in patients with psoriatic arthritis: an in-depth analysis of data from the TOPAS study. Dermatology 2006; 212: 23849.
  • 12
    Clegg DO, Reda DJ, Mejias E, Cannon GW, Weisman MH, Taylor T, et al. Comparison of sulfasalazine and placebo in the treatment of psoriatic arthritis: a Department of Veterans Affairs cooperative study. Arthritis Rheum 1996; 39: 201320.
  • 13
    Collett D. Modeling binary data. London: Chapman and Hall; 1991.
  • 14
    Bombardier C, Maetzel A. Pharmacoeconomic evaluation of new treatments: efficacy versus effectiveness studies? Ann Rheum Dis 1999; 58 Suppl: I825.
  • 15
    Helliwell PS, Taylor WJ. Treatment of psoriatic arthritis and rheumatoid arthritis with disease modifying drugs: comparison of drugs and adverse reactions. J Rheumatol 2008; 35: 4726.
  • 16
    Kingsley GH, Kowalcyzk A, Taylor H, Ibrahim F, Packham JC, McHugh NJ, et al. A randomized placebo-controlled trial of MTX in PsA. Rheumatology (Oxford) 2012; 51: 136877.
  • 17
    De Vlam K, Lories RJ. Efficacy, effectiveness and safety of etanercept in monotherapy for refractory psoriatic arthritis: a 26-week observational study. Rheumatology (Oxford) 2006; 45: 3214.
  • 18
    Heiberg MS, Kaufmann C, Rodevand E, Mikkelsen K, Koldingsnes W, Mowinckel, et al. The comparative effectiveness of anti-TNF therapy and methotrexate in patients with psoriatic arthritis: 6 month results from a longitudinal, observational, multicentre study. Ann Rheum Dis 2007; 66: 103842.
  • 19
    Gladman DD, Mease PJ, Strand V, Healy P, Helliwell PS, Fitzgerald O, et al. Consensus on a core set of domains for psoriatic arthritis. J Rheumatol 2007; 34: 116770.
  • 20
    Gladman DD, Mease PJ, Cifaldi MA, Perdok RJ, Sasso E, Medich J. Adalimumab improves joint-related and skin-related functional impairment in patients with psoriatic arthritis: patient-reported outcomes of the Adalimumab Effectiveness in Psoriatic Arthritis Trial. Ann Rheum Dis 2006; 66: 1638.
  • 21
    Brockbank JE, Stein M, Schentag CT, Gladman DD. Dactylitis in psoriatic arthritis: a marker for disease severity? Ann Rheum Dis 2005; 64: 18890.
  • 22
    Helliwell PS. Therapies for dactylitis in psoriatic arthritis: a systematic review. J Rheumatol 2006; 33: 143941.
  • 23
    Soriano ES, McHugh NJ. Therapies for peripheral joint disease in psoriatic arthritis: a systematic review. J Rheumatol 2006; 33: 142230.