Poster Presentation Australian Diabetes Society and the Australian Diabetes Educators Association Annual Scientific Meeting 2017

BACKGROUND: Residual beta-cell function has been demonstrated in children and adults with type 1 diabetes up to 40 years after diagnosis. Results from the Diabetes Control and Complications Trial indicate that residual beta-cell function is associated with reduced complication risk¹, and also suggests that glycemic variability is a potential contributor to complications in type 1 diabetes, as well as glycemic control. We examined the effect of c-peptide persistence in adults with type 1 diabetes of long duration on glycemic control and variability, as a potential mechanism to explain the reduced  complication risk in those with residual beta-cell function².
METHODS: Clinical factors (age, sex, age at diagnosis, diabetes duration), HbA1c and CGM measures of glycemic control and variability were examined in 69 adults with long term type 1 diabetes in whom ultrasensitive c-peptide was measured (Mercodia c-peptide ELISA, detection limit 1.15 pmol/L, CV 4.8%).
RESULTS: C-peptide was detectable in 21 participants, with a median level of 17.6 pmol/L (range 2.1 to 78.1 pmol/L). Comparing those with undetectable and detectable ultrasensitive c-peptide levels, there was no difference in age (46.7 v 46.5 years), proportion of men (52% v 57%), age at diagnosis (22.1 v 26.7 years), diabetes duration (24.6 v 19.7 years) or HbA1c (8.1% v 8.0%) respectively (P>0.05 for all comparisons). CGM measures of glycemic control and variability were not different between the two groups (P>0.05 for all comparisons).

CONCLUSION: Ultrasensitive c-peptide was detectable in nearly a third of adults with type 1 diabetes of up to 50 years duration. Persistence of ultrasensitive c-peptide in this group was not associated with clinical factors, HbA1c or CGM parameters of glycemic control and variability.