[1] Radboud Univ Nijmegen, Med Ctr, Dept Primary & Community Care, NL-6525 ED Nijmegen, Netherlands
[2] Netherlands Inst Hlth Serv Res NIVEL, Utrecht, Netherlands
[3] Vrije Univ Amsterdam, Med Ctr, Dept Gen Practice, Amsterdam, Netherlands
[4] Vrije Univ Amsterdam, Med Ctr, EMGO Inst Hlth & Care Res, Amsterdam, Netherlands
[5] Vrije Univ Amsterdam, Med Ctr, Dept Epidemiol & Biostat, Amsterdam, Netherlands