β-cell Function in Type 1 Diabetes May Not Be As Low As Presumed

Background and aims: Enhancing endogenous insulin production in type 1 diabetic patients (T1DP) can improve glycemic control and decrease complications and rates of mortality. However, it can be succesfull even if sufficient β-cell function is present. We aimed to evaluate the extent of β-cell function by determining fasting levels of C-peptide and those after meal stimulus.

Materials and Methods: One hundred and thiryfive T1DP were planned to enrolı to the study. Ethics comittee of our hospital approved the study protocol, which was in accordance with the Helsinki Declaration. Fasting C-peptide levels of all participants and stimulated (at 90 th minute post mixed meal) C-peptide levels of 54 will be measured by using an electrochemiluminescence assay. Two categorizations will be done using fasting (the first categorization ) and at 90th minute post mixed meal test (the second categorization) of C-peptide levels. For the first categorization; the groups will be classified as follows: patients with undetectable ≤0.1 ng/mL (group 1); with minimal 0.1-0.8 ng/ml (group 2); and with sustained ≥0.8 ng/mL(group 3) C-peptide levels. For the second categorization, groups will be as follows: patients with undetectable ≤0.1 ng/mL (group 1); with minimal 0.1-0.8 ng/ml (group 2); and with sustained ≥0.8 ng/mL (group 3) C-peptide levels which increased at the 90th minute after the meal ≥150% of fasting C-peptide level.

Inclusion criteria

• Type 1 diabetic patients who have accepted to have mixed meal tolarance test

Exclusion criteria

• Patients with type 2 diabetes,
• patients with MODY