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

Abstract

We investigated whether the addition of metformin to the treatment of overweight and obese individuals further reduces the incidence of type2 diabetes mellitus (T₂DM), 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/m² ) 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 T₂DM 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 T₂DM 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 T₂DM in overweight and obese non-diabetic adults and decreases the rate of MetS by improving the CVD risk factor profile.

metformin - type 2 diabetes mellitus - prediabetes - metabolic syndrome

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