Metformin significantly reduced remnant cholesterol in patients with newly diagnosed type 2 diabetes mellitus after 48-week treatment

Abstract

Abstract Background Metformin has become the first-line therapy for type 2 diabetes mellitus (T2DM) and has beneficial effects on cardiovascular disease (CVD). Remnant cholesterol (RC), the cholesterol of triglyceride-rich lipoproteins, is associated with the risk of CVD. Our research group first explored the relationship between RC and metabolic disorders in China. However, it is still unclear whether metformin could decrease RC. This study aims to investigate the effect of metformin monotherapy on RC in patients with new-onset T2DM. Methods This study was nested in an open-label, randomized trial (MARCH), which was designed to assess the effectiveness of acarbose compared with metformin as the initial therapy for new-onset T2DM. All individuals were diagnosed with T2DM within the past 12 months and had not received any therapy of oral hypoglycemic drugs or lipid-lowering drugs. The primary endpoint was the changes of RC after 48-week metformin treatment. Additionally, we compared alterations in RC among sub-groups divided by the predictor of CVD-atherogenic index of plasma (AIP), low-density lipoprotein cholesterol (LDL-C), body mass index, or hemoglobin A1c. Results After 48-week treatment of metformin, in addition to total cholesterol, triglyceride, LDL-C, RC was also decreased (all P < 0.05) in patients with new-onset T2DM, while the reduction of RC was the most prominent in patients with the highest tertile of AIP. A remarkable decline of RC was observed in both LDL-C < 2.6 mmol/L and LDL-C ≥ 2.6 mmol/L groups, which was greater in participants with LDL-C < 2.6 mmol/L (P < 0.05). Conclusions This study demonstrated that besides improving glucose and conventional lipid profiles, 48-week metformin treatment significantly decreased RC in patients with newly diagnosed T2DM, especially in those with high cardiovascular risk evaluated by AIP and those with well-controlled LDL-C. The results expand the clinical effect of metformin and provide evidence for its clinical usage. Trial Registration ChiCTR.org ChiCTR-TRC-08000231