Variation of fasting serum C-peptide level after admission in Japanese patients with type 2 diabetes mellitus

The aim of this study was to evaluate the variation of fasting serum C-peptide (S-CPR) levels, as a marker for endogenous insulin secretion after admission in Japanese patients with type 2 diabetes mellitus (T2DM). S-CPR levels together with other metabolic factors were measured in 234 T2DM patients twice: at the beginning and at the end of admission for the control of blood sugar levels. As a result, patients were classified into two groups according to their changes of S-CPR (DeltaS-CPR), which consisted of patients whose S-CPR levels had decreased (group D) and increased (group I) after admission. Patients allocated to group I showed younger age, shorter duration of diabetes, and lower basal S-CPR level compared to group D. Conversely, patients in group D showed higher levels of high-sensitivity C-reactive protein (HS-CRP) and brachial-ankle pulse wave velocity compared to group I, suggesting patients in this group are prone to atherosclerosis. DeltaS-CPR was positively correlated with the change of body mass index, waist circumference, and triglycerides in group D. On the other hand, DeltaS-CPR was negatively correlated with the change of HS-CRP in group I, indicating residual beta-cell function could be recovered by the amelioration of inflammatory status in pancreatic islets. It is plausible that Japanese T2DM patients could be classified according to the variation of S-CPR after admission. Evaluation of basal and the variation of S-CPR could provide advantageous information for the management of diabetes mellitus or related disorders.