[1] Pediat II Paediat Rheumatol Int Trials Org, IRCCS Ist G Gaslini, I-16147 Genoa, Italy
[2] Serv Epidemiol & Biostat, IRCCS G Gaslini, Genoa, Italy
[3] Univ Genoa, IRCCS G Gaslini, Genoa, Italy
[4] Great Ormond St Hosp Sick Children, London, England
[5] King Faisal Specialist Hosp & Res Ctr, Riyadh 11211, Saudi Arabia
[6] Univ Utah, Hlth Sci Ctr, Salt Lake City, UT USA
[7] Univ Gothenburg, Gothenburg, Sweden
[8] Univ Ziekenhuis Gent, Ghent, Belgium
[9] Univ Louisville, Sch Med, Louisville, KY 40292 USA
[10] Children Univ Hosp, Bratislava, Slovakia
[11] HealthActCHQ, Boston, MA USA