CONTEXT: Whether continuation of dipeptidyl peptidase-4 inhibitors (DPP-4is) or switching to oral semaglutide is more beneficial for β-cell function is unclear. OBJECTIVE: To assess the efficacy of switching from DPP-4is to oral semaglutide for β-cell function compared with DPP-4i continuation. METHODS: Post hoc analysis of SWITCH-SEMA 2, a multicenter prospective randomized controlled trial on the switch to oral semaglutide vs DPP-4i continuation without dose adjustment for 24 weeks in subjects with type 2 diabetes treated with DPP-4is, was conducted. Changes in markers for glucose metabolism, including homeostatic model assessment (HOMA2) scores and disposition index (DI), were compared between the groups. RESULTS: A total of 146 subjects (semaglutide group, 69
DPP-4i group, 77) were analyzed. In the semaglutide group, glycemic control, liver enzyme deviations, and lipid profiles improved after 24 weeks. Regarding indices for β-cell function, changes in HOMA2-β as well as DI, reflecting the ability of β-cells to compensate for insulin resistance, were significantly higher in the semaglutide group compared with the DPP-4i group (mean change, +10.4 vs +0.6 in HOMA2-β [P = .001] and +0.09 vs 0.0 in DI [P <
.001]). Improvement in DI in the semaglutide group was correlated significantly to changes in body mass index (BMI), HbA1c, and fatty liver index reflecting liver steatosis. Multiple linear regression analysis revealed that dose of semaglutide (≥ 7 mg/day), reduction in fatty liver index, and metformin nonuse were independently associated with improvement of DI. CONCLUSION: Switching to oral semaglutide ameliorated β-cell function compared with DPP-4is, presumably via tissue-to-tissue crosstalk between liver and β-cells.