Systematic review of Difficult-to-treat RA (D2T-RA): 23 articles, 27,987 RA pts from 13 countries - pooled prevalence of D2T-RA was 11.7% (10.9% overall; 13.2% in b/tsDMARDs-treated RA). 47% D2T-RA had persistent inflammatory refractory RA (PIRRA). Prevalence decreased w/ https://t.co/0Gatzbfxid