Summary
Introduction
Psoriatic arthritis (PsA) is a chronic inflammatory disorder characterized by peripheral joint inflammation, nail involvement, enthesitis, tenosynovitis and dactylitis, as well as increased risk of extra-articular manifestations (psoriasis, uveitis, urethritis, inflammatory bowel disease) and other co-morbidities, especially metabolic, cardiovascular and psychological disorders.[1-3] During the last decades, the treatment of PsA has improved dramatically, mainly due to the introduction of biological disease modifying anti-rheumatic drugs (bDMARDs) such as tumor necrosis factor inhibitors (TNFIs).[4] TNFIs are expensive and may cause serious side effects why prescription of these drugs in Denmark is reserved for patients with ongoing, severe disease who are unresponsive to treatment with conventional synthethic (cs)DMARDs. Response to TNFIs is however insufficient in approximately 50% of patients in routine care [5]. Predictors of outcomes to TNFI therapy have been suggested to include clinical, laboratory, lifestyle-related and demographic factors although the overall evidence for specific response modifiers is limited.[6-9] A better understanding of the complex interaction between genetic/biologic and environmental factors is necessary to elaborate risk profiles and personalized treatment recommendations. A gender bias in the prevalence[10] and pathophysiology[11-13] in PsA has been suggested by recent literature and we hypothesize that gender could also play a central prognostic role in relation to therapeutic outcomes. Although some studies already support this idea, the results have been diverging emphasizing the need to further explore this research question.[14]
