Insulin secretion measured by stimulated C‐peptide in long‐established Type 1 diabetes in the Diabetes Control and Complications Trial (<scp>DCCT</scp>)/ Epidemiology of Diabetes Interventions and Complications (<scp>EDIC</scp>) cohort: a pilot study

These results show that a stimulated C-peptide response can be measured in some people with long-term Type 1 diabetes. Further investigation of all participants in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study will help relate long-term residual C-peptide response to glycaemia over time and provide insight into the relevance of this response in terms of insulin dose, severe hypoglycaemia, retinopathy, nephropathy and macrovascular disease. Establishing the clinical relevance of long-term C-peptide responses is important in understanding the impact that therapy to preserve or improve β-cell function may have in patients with long-term Type 1 diabetes.