1. University Hospital, Bern, Switzerland;
2. University Medical Center, Groningen, The Netherlands;
3. HOVON Data Center and Department of Trials and Statistics, Erasmus University Medical Center, Rotterdam, The Netherlands;
4. University Medical Center, Maastricht, The Netherlands;
5. Hôpital Mont Godinne, Yvoir, Belgium;
6. Hôpital St Luc, Bruxelles, Belgium;
7. Academic University Medical Center, Amsterdam, The Netherlands;
8. Erasmus University Medical Center, Rotterdam, The Netherlands;
9. University Hospital, Basel, Switzerland;
10. University Medical Center, Utrecht, The Netherlands;
11. Mesch Spectrum Twente, Enschede, The Netherlands;
12. Department of Internal Medicine III, University-Hospital, Mainz, Germany;
13. University Hospital, Zürich, Switzerland;
14. Kantonsspital, Aarau, Switzerland;
15. University Hospital Gasthuisberg, Leuven, Belgium; and
16. VU University Medical Center, Amsterdam, The Netherlands