Lipid therapy in patients with diabetes mellitus - A joint statement from the Fat Metabolism Commission and the Heart and Diabetes Working Group of the German Diabetes Society (DDG), the Diabetes, Obesity and Metabolism Section of the German Society for Endocrinology (DGE), the German Heart and Diabetes Working Group Society for Cardiology (DGK) and the joint working group Heart - Hormones - Diabetes of the DGK, DGE and DDG