Time to address the challenge of difficult to treat psoriatic arthritis: results from an international survey

Helena Marzo-Ortega, Stephanie R Harrison, György Nagy, Pedro Machado, Dennis McGonagle, Sibel Zehra Aydın, Raquel Almodóvar, Wilson Bautista‐Molano, Laure Gossec, Ennio Lubrano, Peter Nash, Fernando Pimentel‐Santos, Enrique R. Soriano, Stefan Siebert