Therefore, in the present study, we measured the serum GDF15 concentrations from the AIM (the effect of Acarbose on glycemic variability in patients with type 2 diabetes mellitus using premixed Insulin compared to Metformin) study [15] to explore the association between metformin treatment, glycemic control and the change of serum GDF15 levels. The gene discussed is GDF15; the disease is type 2 diabetes mellitus.