[1] Department of Pharmacoepidemiology and Pharmacotherapy,
[2] Utrecht Institute for Pharmaceutical Sciences (UIPS) and Kendle,undefined
[3] PO Box 80.082,undefined
[4] 3508 TB Utrecht,undefined
[5] The Netherlands e-mail: claessens.angela@kendle.com Tel.: +31-30-2537324; Fax: +31-30-2539166,undefined
[6] Department of Medical Sociology,undefined
[7] Health Care Studies,undefined
[8] Faculty of Medicine,undefined
[9] University of Maastricht,undefined
[10] Maastricht,undefined
[11] The Netherlands,undefined
[12] Department of Gastroenterology,undefined
[13] Leiden University,undefined
[14] Leiden,undefined
[15] The Netherlands,undefined