Institute for Medical Biometry and Statistics, Faculty of Medicine and Medical Center - University of Freiburg, Stefan-Meier-Str. 26, Freiburg, 79104, Germany. hieke@imbi.uni-freiburg.de.|Division of Biostatistics, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg, 69120, Germany.|Department of Internal Medicine III, University Hospital of Ulm, Albert-Einstein-Allee 23, Ulm, 89081, Germany.|Institute for Medical Biometry and Statistics, Faculty of Medicine and Medical Center - University of Freiburg, Stefan-Meier-Str. 26, Freiburg, 79104, Germany.|Department of Internal Medicine III, University Hospital of Ulm, Albert-Einstein-Allee 23, Ulm, 89081, Germany.|Institute of Medical Biostatistics, Epidemiology and Informatics, University Medical Center Johannes Gutenberg University Mainz, Obere Zahlbacher Str. 69, Mainz, 55131, Germany.