1. Institute of General Practice, Goethe University, Frankfurt, Germany
2. Department of Consultation-Liaison-Psychiatry and Psychosomatic Medicine, University Hospital Zurich, University of Zurich, Zurich, Switzerland
3. aQua, Institute for Applied Quality Improvement and Research in Health Care, Goettingen, Germany
4. Department of Medical Informatics, Biometry and Epidemiology, Ruhr-University, Bochum, Germany