Gubitosi-Klug RA, Braffett BH, Hitt S, et al. - Researchers sought to examine residual β cell function in Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study candidates with an average 35-year duration of type 1 diabetes mellitus (T1DM). During a 4-hour mixed-meal tolerance test, serum C-peptide was measured. Of the 944 candidates, 117 (12.4%) were classified as responders. Findings suggested that β cell function may persist in long-duration T1DM. With a peak C-peptide concentration > 0.03 nmol/L, clinically significant reductions in the prevalence of severe hypoglycemia have been observed.