Jeyam A, Colhoun H, McGurnaghan S, et al. - Researchers aimed at quantifying the correlation of residual C-peptide secretion with glycemic outcomes and microvascular complications in type 1 diabetes. They monitored C-peptide measures determined in an untimed blood sample in the Scottish Diabetes Research Network Type 1 Bioresource (SDRNT1BIO) cohort of 6,076 people with type 1 diabetes for an average of 5.2 years. Findings from this large representative cohort suggest clinical benefit of even minimal residual C-peptide secretion in type 1 diabetes, which is in contrast to a follow-up study of the Diabetes Control and Complications Trial (DCCT) intensively treated cohort where an effect on hypoglycemia was observed only at C-peptide levels ≥ 130 pmol/L. This has apparent implications for the design and evaluation of trials of interventions to conserve or restore pancreatic islet function in type 1 diabetes.