1. Institute of Health Services Research and Health Economics German Diabetes Center Düsseldorf Germany
2. Institute of Health Services Research and Health Economics, Centre for Health and Society Medical Faculty of the Heinrich‐Heine University Düsseldorf Germany
3. Deutsches Zentrum für Diabetesforschung German Center for Diabetes Research (DZD) Neuherberg Germany
4. Cochrane Metabolic and Endocrine Disorders Group, Institute of General Practice Medical Faculty of the Heinrich‐Heine University Düsseldorf Germany