1. Institute of Health Economics and Clinical Epidemiology, University of Cologne, Cologne, Germany/DRK Kamillus Klinik Asbach, Asbach, Germany
2. Institute of Medical Statistics, Informatics and Epidemiology, University of Cologne, Cologne, Germany
3. Zentrum für Therapeutisches Reiten Johannisberg e.V., Windhagen, Germany
4. Department of Health Sciences/Public Health, School of Medicine, Dresden University of Technology, Dresden, Germany
5. Institute of Health Economics and Clinical Epidemiology, University of Cologne, Cologne, Germany/School of Health Professions, Zurich University of Applied Sciences (ZHAW), Winterthur, Switzerland
6. DRK Kamillus Klinik Asbach, Asbach, Germany