Postprandial Serum C-peptide is a Useful Parameter in the Prediction of Successful Switching to Liraglutide Monotherapy from Complex Insulin Therapy in Japanese Patients with Type 2 Diabetes

Aims: Liraglutide improves glycemic control in patients with type 2 diabetes. However, no information is available about an indicator of successful switching to liraglutide monotherapy from complex insulin therapy in Japanese patients with type 2 diabetes.

Methods: We studied 69 patients with type 2 diabetes, including 39 consecutive successful patients and 30 consecutive unsuccessful patients from insulin therapy to liraglutide monotherapy. Before switching, we measured urinary C-peptide, fasting C-peptide and postprandial C-peptide at 30, 60 and 120 min loading a test meal. In successful patients, HbA(1c) and body weight were measured at 4, 8, and 12 weeks after switching.

Results: Using univariate analysis, duration of disease was significantly higher in unsuccessful patients than in successful patients. Urinary C-peptide, fasting C-peptide, and postprandial C-peptides were significantly higher in successful patients than in unsuccessful patients. Multiple logistic regression analysis showed that postprandial C-peptide at 60 min was an independent predictor of successful switching to liraglutide monotherapy from insulin therapy (odds ratio, 7.28; 95% confidence interval, 2.89-18.36). In the receiver operating characteristic analyses, 2.9 ng/mL of postprandial C-peptide at 60 min was the best cut-off value, providing that sensitivity and specificity were 95% and 93%, respectively. In the follow-up period, successful patients showed a sustained reduction in HbA(1c) and body weight without hypoglycemia.

Conclusions: Postprandial C-peptide at 60 min is a useful parameter in the prediction of successful switching from insulin therapy to liraglutide monotherapy in Japanese patients with type 2 diabetes.