Acarbose compared with metformin as initial therapy in patients with newly diagnosed type 2 diabetes: an open-label, non-inferiority randomised trial

Background Metformin is the only first-line oral hypoglycaemic drug for type 2 diabetes recommended by international guidelines with proven efficacy, safety, and cost-effectiveness. However, little information exists about its use in Asian populations. We aimed to ascertain the effectiveness of the α-glucosidase inhibitor acarbose, extensively adopted in China, compared with metformin as the alternative initial therapy for newly diagnosed type 2 diabetes. Methods In this 48-week, randomised, open-label, non-inferiority trial, patients who were newly diagnosed with type 2 diabetes, with a mean HbA1c of 7·5%, were enrolled from 11 sites in China. After a 4-week lifestyle modification run-in, patients were assigned to 24 weeks of monotherapy with metformin or acarbose as the initial treatment, followed by a 24-week therapy phase during which add-on therapy was used if prespecified glucose targets were not achieved. Primary endpoints were to establish whether acarbose was non-inferior to metformin in HbA1c reduction at week 24 and week 48 timepoints. The non-inferiority margin was 0·3%, with an expected null difference in the change from baseline to week 48 in HbA1c. Analysis was done on a modified intention-to-treat population. This study was registered with Chinese Clinical Trial Registry, number ChiCTR-TRC-08000231. Findings Of the 788 patients randomly assigned to treatment groups, 784 patients started the intended study drug. HbA1c reduction at week 24 was −1·17% in the acarbose group and −1·19% in the metformin group. At week 48, the HbA1c reduction was −1·11% (acarbose) and −1·12% (metformin) with difference 0·01% (95% CI −0·12 to 0·14, p=0·8999). Six (2%) patients in the acarbose group and seven (2%) patients in the metformin group had serious adverse events, and two (1%) and four (1%) had hypoglycaemic episodes. Interpretation This study provides evidence that acarbose is similar to metformin in efficacy, and is therefore a viable choice for initial therapy in Chinese patients newly diagnosed with type 2 diabetes. Funding Bayer Healthcare (China) and Double Crane Phama.