Psoriatic arthritis (PsA) Is a chronic autoimmune inflammatory condition that has skin and joint components. Understanding the pathophysiology of the disease has paved the way for a breakthrough in its management with the introduction of antitumour necrosis factor therapies (TNFs). However, little is known about their long-term risk-benefit profile, as well as, long-term persistence with these therapies in patients with PSA. The aim of this thesis was to conduct a meta-analysis of published randomised controlled trials followed by a longitudinal observational study of the use of anti-TNF therapies in PSA.