Efficacy and tolerability of sitagliptin and metformin compared with insulin as an initial therapy for newly diagnosed diabetic patients with severe hyperglycaemia

The safety and efficacy of dipeptidyl peptidase-4 inhibitors in patients newly diagnosed type 2 diabetes mellitus (T2DM) with severe hyperglycaemia have remained to be sufficiently demonstrated. The aim of the present study was to determine whether sitagliptin combined with metformin as an initial treatment had non-inferior outcomes with regards to glycaemic remission and β-cell function recovery to those of standard insulin therapy in this patient group. A prospective observational study was performed comparing the effects of sitagliptin combined with metformin and insulin therapy in a real-world clinical setting. A total of 168 participants were enrolled and received sitagliptin combined with metformin (Sig) or insulin (Ins) for almost 4 weeks. In addition, each group was further stratified into three subgroups, according to glycosylated haemoglobin (HbA1c) levels (<10, 10-12 and >12%). The primary outcomes were β-cell function and changes in fasting plasma glucose (FPG) and HbA1c at the 3-month follow-up. Both insulin and sitagliptin combined with metformin reduced hyperglycaemia and achieved similar glycaemic outcomes, and no significant differences in FPG and HbA1c levels were obtained. No significant changes were observed in β-cell function concomitant with the glucose-lowering effects of the treatments. Of note, participants in the Ins group exhibited weight gain, whereas those in the Sig group had weight loss, with significant differences becoming evident after 1 month, particularly in the HbA1c <10% subgroup. As compared with insulin injection, early treatment with sitagliptin combined with metformin in newly diagnosed patients with T2DM and severe hyperglycaemia produced non-inferior outcomes with regards to glycaemic remission. Therefore, combination of sitagliptin and metformin may be a viable initial treatment option for patients who prefer an alternative to insulin injection. This study was registered with ClinicalTrials.gov under no. NCT03180281.