Guselkumab provides durable improvement across psoriatic arthritis disease domains: post hoc analysis of a phase 3, randomised, double-blind, placebo-controlled study by Coates, LC, Gossec, L, Zimmermann, M, Shawi, M, Rampakakis, E, Shiff, NJ, Kollmeier, AP, Xu, XL, Nash, P, Mease, PJ, Helliwell, PS