Comparison of glycemic control and β-cell function in new onset T2DM patients with PCOS of metformin and saxagliptin monotherapy or combination treatment

BACKGROUND: Impaired insulin activity in women with polycystic ovary syndrome might differ from that seen in type 2 diabetes mellitus without polycystic ovary syndrome. This study was designed to compare the effects of treatment with metformin, saxagliptin, and their combination in newly diagnosed women with type 2 diabetes mellitus and polycystic ovary syndrome in China. METHODS: A total of 75 newly diagnosed patients from Shanghai, China with type 2 diabetes mellitus and polycystic ovary syndrome were included in this randomized, parallel, open-label study. All patients received treatment for 24 weeks with metformin, saxagliptin, or their combination. Patients were allocated to one of three treatment groups by a computer-generated code that facilitated equal patient distribution of 25 patients per group. The primary outcome was a change in glycemic control and β-cell function. RESULTS: A total of 63 patients completed the study (n = 21, for each group). The reduction in hemoglobin A1c was significant in the combination group, compared to the monotherapy groups (saxagliptin vs. combination treatment vs. metformin: − 1.1 vs. -1.3 vs. -1.1%, P = 0.016), whereas it was comparable between the metformin and saxagliptin groups (P > 0.05). Saxagliptin, metformin, and the combination treatment significantly reduced the homeostasis model assessment- insulin resistance index and increased the deposition index (P < 0.01 for all). However, no significant change was observed in the homeostasis model assessment- β-cell function among the metformin and combination groups, and no significant changes were observed in the insulinogenic index among all three groups (P > 0.05 for all). In addition, saxagliptin and metformin treatments significantly reduced body mass index and high-sensitivity C-reactive protein levels (P < 0.01 for both). CONCLUSIONS: Saxagliptin and metformin were comparably effective in regulating weight loss, glycemic control, and β-cell function, improving lipid profiles, and reducing inflammation in newly diagnosed type 2 diabetes mellitus patients with polycystic ovary syndrome. TRIAL REGISTRATION: ChiCTR-IPR-17011120 (retrospectively registered on 2017–04-12). ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12902-018-0243-5) contains supplementary material, which is available to authorized users.