[1] Katholieke Univ Leuven, Dept Publ Hlth & Primary Care, Kapucijnenvoer 33,Blok J,PB 7001, B-3000 Leuven, Belgium
[2] Univ Antwerp, Dept Primary & Interdisciplinary Care, Antwerp, Belgium
[3] Norwegian Inst Publ Hlth, Div Hlth Serv, Oslo, Norway
[4] Univ Ghent, Dept Pharmacol, Ghent, Belgium
[5] Flemish Coll Gen Practitioners, Domus Med, Antwerp, Belgium
[6] EBMPracticeNet, Leuven, Belgium