In the current study, we observed that drug naïve diabetic patients treated with metformin combination with CSII therapy experienced a significant reduction in the total daily insulin doses, bolus insulin doses, and basal insulin doses to maintain euglycemic control, the shorter times to achieve euglycemic control, the improvement in glycemic variation and associated with no increase of hypoglycemia, which indicates that metformin combined with CSII therapy can be considered a safe and valuable treatment option. The gene discussed is INS; the disease is Hypoglycemia.