[1] Harvard Univ, Brigham & Womens Hosp, Sch Med, Dept Med,Div Pharmacoepidemiol & Pharmacoecon, Boston, MA 02115 USA
[2] Univ Vienna, Dept Med 3, Div Nephrol & Dialysis, Vienna, Austria
[3] Krankenhaus Kreuzschwestern Wels, Austrian Dialysis & Transplant Registry, Wels, Austria
[4] Univ Vienna, Clin Inst Med & Chem Lab Diagnost, Vienna, Austria