1 Institute of Medical Informatics, Biometry and Epidemiology, University Hospital Essen, 45147 Essen, Germany. Electronic address: fabian.standl@uk-essen.de.
2 Institute of Medical Informatics, Biometry and Epidemiology, University Hospital Essen, 45147 Essen, Germany.
3 Department of Trauma, Hand and Reconstructive Surgery, University Hospital Essen, 45147 Essen, Germany.
4 Institute of Medical Informatics, Biometry and Epidemiology, University Hospital Essen, 45147 Essen, Germany; School of Public Health, Department of Epidemiology, Boston University, Boston, MA, USA.