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

Abstract 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, HbA1c 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 HbA1c 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.