The effect of metformin on the incidence of type 2 diabetes mellitus and cardiovascular disease risk factors in overweight and obese subjects--the Carmos study.

We investigated whether the addition of metformin to the treatment of overweight and obese individuals further reduces the incidence of type2 diabetes mellitus (T 2 DM), prediabetes and metabolic syndrome (MetS) and improves cardiovascular disease (CVD) risk factors (RFs). Design and methods: We studied 366 adults (mean age 53.0±0.5 SE years, and mean BMI 32.3±0.2 SE Kg/m 2 ) without CVD. All subjects received lifestyle recommendations and drug management of CVD-RFs, whilst 95 of them were additionally given metformin. The follow-up period lasted 12 months. Results: At the end of the study the frequency of T 2 DM in the metformin and non-metformin group was 1.1 and 8.1%, respectively (risk difference=-7% with 95% CI from -12.7% to -1.4%, p=0.012). Participants with prediabetes displayed a greater reduction in the incidence of T 2 DM after taking metformin compared to those who had not received this drug (risk difference=-18.5% with 95%CI from -33.1% to -3.9%, p=0.010). Metformin had a similar beneficial impact on subjects with MetS (risk difference = -12.9% with 95 % from -25 % to - 0.7 %, p=0.040) and this was attributed to the greater increase in HDL-C (p=0.046) and decrease in fasting plasma glucose levels (p=0.024). Metformin also achieved a greater reduction in total cholesterol and LDL-C levels (metformin vs. non-metformin treated subjects: -31.9 vs. -17.3 mg/ dl, p = 0.001, and - 26.2 vs. -15.9 mg/dl, p=0.006, respectively). Conclusions: Metformin reduces the occurrence of T 2 DM in overweight and obese non-diabetic adults and decreases the rate of MetS by improving the CVD risk factor profile.