1. Institute of General Practice, Rostock University Medical Center, 18055 Rostock, Germany
2. Department of General Practice and Health Services Research, University Hospital Heidelberg, 69120 Heidelberg, Germany
3. Institute of Medical Biometry, University Hospital Heidelberg, 69117 Heidelberg, Germany
4. aQua-Institute for Applied Quality Improvement and Research in Health Care GmbH, 37073 Göttingen, Germany
5. Department of Communication Design and Media, University of Applied Sciences, Technology, Business and Design, 23966 Wismar, Germany