Table 1 Inclusion and exclusion criteria

Diagnosis of T2DM with insulin therapy for at least 3 months and an HbA1c of ≥7%; negative islet cell autoantibody testing will be required for patients that received insulin therapy within 1 year after T2DM diagnosis

Type I diabetes mellitus or latent autoimmune diabetes of adults (LADA)

Proof of at least one microvascular manifestation of diabetes (for example, nephropathy, retinopathy, neuropathy)

T2DM on diet and/or oral medication

Residual pancreatic function, which is the premise for autogenic glycemic control assessed by stimulated fasting C-peptide laboratory tests with a minimum of 1.5 ng/mL

Heart failure (NYHA III-IV)

Pregnancy

BMI 26–35 kg/m²

Malignant disease in the past 5 years

Age 30 to 65 years

History of major abdominal operation

Permanent glucocorticoid or other immunosuppressive therapy

Pituitary disease/Morbus Addison

Renal failure (glomerular filtration rate < 45 ml/min)

Proof of any liver cirrhosis above grade A according to the Child-Pugh-classification

Expected lack of compliance or inability to informed consent