[1] Univ Groningen, Univ Med Ctr Groningen, Dept Internal Med, Groningen, Netherlands
[2] Med Ctr Leeuwarden, Dept Internal Med, Leeuwarden, Netherlands
[3] Onze Lieve Vrouw Hosp, Dept Internal Med, Amsterdam, Netherlands
[4] Diakonessen Hosp, Dept Internal Med, Meppel, Netherlands
[5] Sint Franciscus Gasthuis Rotterdam, Dept Internal Med, Rotterdam, Netherlands