Our results would support the notion that patients with PsA have higher persistence rates with anti-TNF therapies than RA patients; an earlier analysis of RA patients (n = 6,739) registered with the BSRBR found that 65% of the observed RA cohort persisted with their primary anti-TNF therapy over a mean length of follow-up of 15 months [22]. This evidence concerns the gene TNF and rheumatoid arthritis.