C-Peptide Changes and Glycemic Response During DPP-4 Versus SGLT2 Inhibitor Therapy in Type 2 Diabetes: The Role of Baseline C-Peptide

Background and Objective: To compare longitudinal changes in serum C-peptide during dipeptidyl peptidase-4 (DPP-4) inhibitor versus sodium–glucose cotransporter 2 (SGLT2) inhibitor therapy in type 2 diabetes and to evaluate whether baseline C-peptide predicts glycemic response. Materials and Methods: This single-center retrospective new-user cohort study included 196 adults with type 2 diabetes who initiated a DPP-4 inhibitor (n = 99) or an SGLT2 inhibitor (n = 97) following a 12-month washout period. Baseline and follow-up HbA1c, plasma glucose, and fasting C-peptide measurements were assessed over a mean follow-up of 156 days. Glycemic response was defined as an HbA1c reduction of at least 1.0 percentage point. Multivariable linear and logistic regression analyses were performed, and receiver operating characteristic analysis evaluated the predictive performance of baseline C-peptide.