https://imcjms.com/public Ibrahim Medical College Journal of Medical Science https://imcjms.com/public/registration/journal_full_text/317 Thu, 25 Apr 2019 09:20:22 +0000 Abstract Background and objectives: Metformin improves macrovascular complications in people with diabetes mellitus (DM). Although the exact mechanism is not known, metformin has beneficial effects on dyslipidaemia. The aim of the study was to find out if there was an effect of metformin on blood lipids in people with diabetes mellitus. Method: This was a cross-sectional study which included 80 patients with diabetes mellitus. They were divided into 2 groups – (a) Group 1: on metformin and (b) Group 2: without metformin medication. None of the patients were on any other anti-diabetic medication. All data were obtained from patients’ medical records. Individual blood lipids and lipid ratios were compared between two groups. Result: Group 1 included 42 patients with a mean HbA1c of 7.58 ± 0.24% taking an average dose of 820.83 ± 60.40 mg/day of metformin. Group 2 consisted of 38 patients with mean HbA1c of 7.58 ± 0.29%. There was no significant difference in individual plasma lipid levels, lipoprotein ratio or frequency of dyslipidaemia between patients taking and not taking metformin (p>0.05). Also, different doses of metformin had no significant effect on the plasma lipid levels. Conclusion: Metformin did not affect the lipid profile of patients with diabetes mellitus. IMC J Med Sci 2019; 13(2): 004. EPub date: 22 August 2019. DOI: https://doi.org/10.3329/imcjms.v13i2.45277 Address for Correspondence: Dr. Tahniyah Haq, Assistant Professor, Department of Endocrinology, Room 1620, 15th Floor, Block D, Bangabandhu Sheikh Mujib Medical University, Shahbag, Dhaka 1000, Bangladesh. Email: tahniyah81@gmail.com   Introduction There is a multitude of evidence from both observational and intervention studies that metformin improves long-term macrovascular complications in people with type 2 diabetes mellitus [1]. It is associated with a 39% reduction in the incidence of myocardial infarction in diabetes [2]. Although, it is known that this favourable cardiovascular effect is independent of its anti-diabetic action, the exact mechanism is still being studied [3]. Metformin has modest positive effects on dyslipidaemia, inflammation and thrombosis, benefiting vascular function [3]. Some studies have described that metformin lowers very low density cholesterol (VLDL), triglyceride, low density lipoprotein (LDL), plasminogen activator inhibitors, factor VIII, C-reactive protein, and increases high density lipoprotein (HDL), especially if abnormal [2]. It also stabilizes fibrin and platelets [2]. However, others show no significant effect on blood lipids [4]. There may be several reasons why we did not find any association between lipid profile and metformin use in our study. Studies have shown that metformin reduces intestinal lipoprotein synthesis when used in high doses, of approximately 2300 mg/day [5]. Therefore, an explanation for the lack of effect of metformin on lipid profile may be the low dose (less than 1700 mg/day) used by the patients in this study. Unfortunately, the duration of metformin use was not available from the database. So, we do not know if metformin had sufficient time to affect blood lipids. In randomized controlled trials to see effect of metformin on lipids, metformin was used for at least 6 weeks [12]. Some reports have indicated that the lipid lowering effect of metformin is more pronounced when baseline lipids are markedly elevated [4]. The baseline lipid levels were however not substantially elevated in this study. This may contribute to the lack of difference seen between the two groups. In case of near normal glycaemic control, metformin had no effect on triglycerides but still affected the total and LDL cholesterol [12]. The HbA1c level was near normal in our study population. This may explain why a difference in triglyceride level was not found. A limitation of this study is its cross-sectional nature with small number of DM cases in both arms. This did not allow us to rigorously control the study to see the effect of introducing metformin on lipid profile. Further prospective study involving larger study population and defined criteria is needed to ascertain the effect of metformin on plasma lipids in ethnic Bengali DM population. In conclusion, metformin had no effect on lipid profile and lipoprotein ratios in our study population.   Author’s contributions TH designed the study, collected samples, analyzed data, wrote and edited the manuscript. 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