Therefore, based on the data of the Observational Registry for BI Treatment (ORBIT) study [21], we analyzed the combination of metformin with BI initiation, and compare the effectiveness and safety between BI users with and without metformin among Chinese population in real-world, with the ultimate purpose of improving the practical adherence to guidelines on metformin use and identifying further researches to improve diabetes care during insulin transition. This evidence concerns the gene INS and diabetes mellitus.