Department of Endocrinology and Diabetology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany. Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine-University, Düsseldorf, Germany. German Center for Diabetes Research, Partner Düsseldorf, Neuherberg, Germany. Landesapotheke Salzburg, Department of Production, Hospital Pharmacy, Salzburg, Austria. Institute for Biometrics and Epidemiology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich-Heine-University, Düsseldorf, Germany. Department of Endocrinology and Diabetology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Düsseldorf, Germany. michael.roden@ddz.de. Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine-University, Düsseldorf, Germany. michael.roden@ddz.de. German Center for Diabetes Research, Partner Düsseldorf, Neuherberg, Germany. michael.roden@ddz.de.