[1] Pallas Hlth Res & Consultancy, Rotterdam, Netherlands
[2] Polish Inst Evidence Based Med, Krakow, Poland
[3] Hosp Univ Germans Trias i Pujol, Barcelona, Spain
[4] Univ Autonoma Barcelona, E-08193 Barcelona, Spain
[5] Univ Padua, Dept Pediat, Padua, Italy
[6] Univ Tampere, Sch Med, FIN-33101 Tampere, Finland