Current status of metformin in addition to insulin therapy in adult patients with type 1 diabetes mellitus: An analysis from the Guangdong Type 1 Diabetes Mellitus Translational Medicine Study

Abstract

Limited data on the efficacy of the additional metformin therapy in patients with type 1 diabetes mellitus (T1DM) under real-life conditions have been available so far. Patients aged ≥18 years with a duration of T1DM for at least 1 year were included in this multicenter observational study. Patients with insulin combined with metformin therapy (MET group) were compared with those with insulin therapy only (INS group). A total of 76 patients in the MET group were compared with 655 patients in the INS group. At baseline, patients with dyslipidemia were more prevalent in the MET group (17.6% vs 9.0%; P = .006), and they also had a higher body mass index (BMI) (21.7 ± 3.2 kg/m2 vs 20.4 ± 2.6 kg/m2 ; P < .001) than those in the INS group. But glycosylated hemoglobin (HbA1c) and daily insulin dose were not significantly different between the two groups. After 1-year follow-up, HbA1c decreased in both groups, while the daily insulin dose decreased in the MET group, but did not change in the INS group (-0.02 IU/kg [-0.16, 0.09] vs 0 IU/kg [-0.09, 0.09]; P = .029). The additional metformin therapy led to no change of BMI and weight in the MET group, while the body weight increased from 53.7 ± 8.6 kg to 55.0 ± 7.9 kg in the INS group (P < .001). Metformin is initiated more in T1DM patients with dyslipidemia or higher BMI in current practice in China. The addition of metformin is effective in maintaining weight and reducing the insulin dosage without improving glycemic control in patients with T1DM.