Variables associated with persistence of C-Peptide secretion among patients with Type 1 diabetes mellitus

Abstract

Background: C-peptide is a reliable method for estimating the beta-cell residual function. The objective of this study to assess the variables associated with persistence of C-peptide secretion among patients with Type 1 diabetes mellitus (T1DM). Patients and Methods: This was a cross-sectional study conducted from October 2015 to September 2016. This study enrolled patients with T1DM with at least 1 year or more duration. Random C-peptide with concomitant plasma glucose at least 144 mg/dl (8 mmol/l) was measured and at this cutoff considered as a stimulated value. Variables that were assessed were age at the time of enrollment, age at the diagnosis of diabetes, gender, family history of diabetes, duration of diabetes, frequency of insulin per day, insulin dose (units/kg/day), type of insulin, devices delivery, body mass index (BMI) at enrollment, blood pressure, glucose (plasma), lipid profile, glycated hemoglobin (HbA1c), thyrotropin (TSH), and antibodies to glutamic acid decarboxylase (GAD65), thyroid peroxidase antibodies (anti-TPO), and tissue transglutaminase antibodies-IgA (anti-TTG-IgA). Results: A total 324 patients were included in the study. A higher level of C-peptide has been seen if the disease acquired at the age of 18 years and older with detectable C-peptide observed among 17.7% of those diagnosed at age <18 years versus 31.7% for those aged 18 years or above. The more the duration of diabetes, the more is the loss of C-peptide. On logistic regression analysis, only duration of diabetes <6 years, and insulin dose <1 U/kg/day were statistically significantly associated with the detectable level of C-peptide in this cohort of T1DM. Conclusion: Diagnosis of TIDM at a late age, positive family history of diabetes, those requiring <1 U of insulin per kg per day, and higher fasting glucose was associated with higher and more detectable C-peptide. On multivariable analysis, the only duration of diabetes <6 years and insulin dose <1 U of insulin per kg per day remains significantly associated with detectable C-peptide after at least 1 year from the diagnosis of T1DM. The gender, the BMI, blood pressure, the number of insulin injections per day, GAD65, anti-TTG-IgA, anti-TPO antibodies together with random glucose, lipid profile, HbA1c, or TSH levels failed to predict detectable C-peptide at 1 year from the diagnosis of T1DM.

Keywords

• C-peptide
• persistence
• Type 1 diabetes mellitus