C-peptide concentrations in patients with type 2 diabetes treated with insulin

To determine beta cell reserves of patients with type 2 diabetes who are treated with insulin by using fasting C-peptide concentrations and to investigate the clinical features related to C-peptide concentrations.

Patients with type 2 diabetes, who were using insulin as monotherapy or in combination therapy, were divided into three groups; those with an insufficient beta cell reserve (C-peptide: <0.5 ng/mL), borderline reserve (C-peptide: 0.5-2 ng/mL) and sufficient reserve (C-peptide:> 2 ng/mL).

In the 249 patients (mean age, 61.77 ± 9.34 years; 40.6% male), the mean duration of diabetes was 13.9 ± 8.43 years. The mean HbA1c concentrations, fasting glucose and C-peptide concentrations were 8.88 ± 1.87%, 184.29 ± 77.88 mg/dL and 1.95 ± 1.37 ng/mL, respectively. Fifty-seven percent of patients (n = 142) had a borderline beta cell reserve and 37% (n = 92) had high C-peptide concentrations. Only 6% of patients (n = 15) had an insufficient beta cell reserve. C-peptide levels were positively correlated with waist circumference (r: 0.282; p = 0.001), hip circumference (r: 0.251; p = 0.001), body mass index (r: 0.279; p = 0.001), fasting glucose concentrations (r: 0.309; p = 0.001) and triglyceride concentrations (r: 0.358; p = 0.001).

In this study, almost all patients with type 2 diabetes using insulin were found to have sufficient or borderline beta cell reserves and insulin resistance-related parameters were prominent in those with adequate beta cell reserve.

NCT04005261.