Positive association between the proinsulin-to-C-peptide ratio and prolonged hyperglycemic time in type 2 diabetes.

ABSTRACT

The proinsulin-to-C-peptide (PIC) ratio is an index applied during the early stage of pancreatic ß-cell dysfunction. The aim of this study was to identify the characteristics associated with the PIC ratio to discuss pancreatic ß-cell dysfunction progression during the natural course of type 2 diabetes and its relationship with glycemic management. This multicenter, prospective observational study included 272 outpatients with type 2 diabetes. Continuous glucose monitoring was performed and fasting blood samples were collected and analyzed. We identified the clinical factors associated with the PIC ratio by multiple regression analysis. The mean age of the cohort was 68.0 years, mean hemoglobin A1c 7.1% (54 mmol/mol), and mean body mass index 24.9 kg/m2. Multiple regression analysis showed that a prolonged time above the target glucose range (>180 mg/dL) and high body mass index contributed to a high PIC ratio. However, no associations were found between the PIC ratio and glucose variability indices. These findings suggested that the PIC ratio is positively associated with a prolonged hyperglycemic time in type 2 diabetes, whereas its relationship with glucose variability remains unclear.