C-peptide secreted by β cells has a common precursor proinsulin with insulin. Proinsulin can be decomposed into one molecule of insulin and one molecule of C-peptide. C-peptide is not easily degraded by the liver and hence reflects the content of insulin in the body through the detection of the level of C-peptide.

A retrospective study which was conducted on 271 T2DM patients treated with insulin pumps from 2016 to 2018 attempted to explore the insulin requirement profiles and analyze the related factors of type-2 diabetes mellitus (T2DM) with different C-peptide levels on insulin pump therapy. The cohort was subdivided into groups according to the ratio of C-peptide at 2 h after meals to fasting C-peptide (C2h/C0), and the dosage of insulin and influencing factors were analyzed.

The study results reveal that in a group with C2h/C0 < 2.5 the percentage of the base amount in total was higher than in group with group C2h/C0 ≥ 2.5(P < 0.05). There was also an observed correlation between C2h/C0 and waist circumference, HbA1c, Fasting Plasma Glucose (FPG) and blood glucose 2 h after meal (2hPG) (P < 0.05).

The study concluded that the basal premeal dose ratio of T2DM with different C-peptide levels differs during intensive insulin pump therapy and parameters which indicate glycemic control and β-cell function should be taken into consideration for total insulin requirements.