1. Prey S, Paul C, Bronsard V, Puzenat E, Gourraud PA, Aractingi S, Aubin F, Bagot M, Cribier B, Joly P et al (2010) Assessment of risk of psoriatic arthritis in patients with plaque psoriasis: a systematic review of the literature. J Eur Acad Dermatol Venereol 24(Suppl 2):31–35. doi:10.1111/j.1468-3083.2009.03565.x
2. Augustin M, Spehr C, Radtke MA, Boehncke WH, Luger T, Mrowietz U, Reusch M, Stromer K, Wozel G, Kiedrowski R von et al (2014) German psoriasis registry PsoBest: objectives, methodology and baseline data. J Dtsch Dermatol Ges 12(1):48–57. doi:10.1111/ddg.12233
3. Reich K, Kruger K, Mossner R, Augustin M (2009) Epidemiology and clinical pattern of psoriatic arthritis in Germany: a prospective interdisciplinary epidemiological study of 1511 patients with plaque-type psoriasis. Br J Dermatol 160(5):1040–1047. doi:1010.1111/j.1365-2133.2008.09023.x
4. Villani AP, Rouzaud M, Sevrain M, Barnetche T, Paul C, Richard MA, Beylot-Barry M, Misery L, Joly P, Le Maitre M et al (2015) Prevalence of undiagnosed psoriatic arthritis among psoriasis patients: Systematic review and meta-analysis. J Am Acad Dermatol 73(2):242–248. doi:210.1016/j.jaad.2015.1005.1001
5. Kimball AB, Leonardi C, Stahle M, Gulliver W, Chevrier M, Fakharzadeh S, Goyal K, Calabro S, Langholff W, Menter A (2014) Demography, baseline disease characteristics and treatment history of patients with psoriasis enrolled in a multicentre, prospective, disease-based registry (PSOLAR. Br J Dermatol 171(1):137–147. doi:110.1111/bjd.13013