[1] Kings Coll London, Acad Dept Rheumatol, London, England
[2] Charles Univ Prague, Fac Med 1, Inst Rheumatol, Prague, Czech Republic
[3] Charles Univ Prague, Fac Med 1, Dept Rheumatol, Prague, Czech Republic
[4] Kings Coll London, Primary Care & Publ Hlth Sci, London, England
[5] Univ Manchester, Arthrit Res UK Epidemiol Unit, Manchester, Lancs, England