C-peptide Measurement may not be Necessary for Choosing a Treatment Modality in Type 2 Diabetes Mellitus: A Retrospective Analysis

ABSTRACT

Purpuse: C-peptide (CP), generated during the cleavage of proinsulin to form insulin, serves as a specific marker of insulin-secreting beta cell function. Since CP is utilized to assess the secretion of insulin, it may act as an indicator in the treatment algorithm of diabetes. The present retrospective study aimed to demonstrate whether patients previously diagnosed with type–2 diabetes (T2DM) and on antidiabetic treatment received the recommended CP-guided treatment mentioned in the current guideline.

Material and Method: A total of 179 patients, previously diagnosed with T2DM, were admitted to our outpatient clinic with complete clinical records and simultaneously measured fasting CP, glucose, and hemoglobin A1c (HbA1c) levels. We did not use the CP levels measured during the current course of treatment as a marker to designate or change treatment in the current study. Data were analyzed using the SPSS version 17.0.

Results: The mean CP level for all patients was 2.71 ng/mL. Twelve patients (6.7%) had insufficient reservoir (CP < 0.5 ng/mL), 70 (39.1%) exhibited borderline reservoir (CP: 0.5–2.0 ng/mL), and 97 (54.2%) had sufficient reservoir of beta cells. All three groups were similar regarding age, gender, fasting glucose, and HbA1c. Metformin was more frequent in patients with sufficient reservoir, whereas all patients in the insufficient group were taking insulin.

Conclusion: Although the literature on diabetes provides enough evidence on the use of CP in various indications, such as determining diabetes subtype, predicting treatment response, and residual beta cell reservoir, we conclude that it may have a limited use as factor deciding the choice of treatment in patients with T2DM.