Institute for Medical Informatics, Biometry and Epidemiology, University of Duisburg-Essen, Hufelandstr, 55, D-45122 Essen, Germany. markus.neuhaeuser@medizin.uni-essen.de|Institute for Medical Informatics, Biometry and Epidemiology, University of Duisburg-Essen, Hufelandstr, 55, D-45122 Essen, Germany. markus.neuhaeuser@medizin.uni-essen.de|Institute for Medical Informatics, Biometry and Epidemiology, University of Duisburg-Essen, Hufelandstr, 55, D-45122 Essen, Germany. markus.neuhaeuser@medizin.uni-essen.de