Abstract

Background
Metformin is an oral medication most commonly prescribed to lower blood glucose levels. However, previous systematic reviews have cast doubt on its effectiveness in reducing the risk of cardiovascular disease (CVD), the costliest side effect of type 2 diabetes mellitus (T2DM).
Objective
This study aimed to combine data from observational studies and randomised controlled trials to determine the impact of metformin on cardiovascular outcomes in diabetic and non-diabetic population.
Methods
On February 24, 2023, a thorough article search was performed in PubMed, EBSCO, Scopus, Web of Science, and ProQuest using keywords and synonyms of Metformin and CVD, coupled with specific terms for different CVDs. Study quality was evaluated using the Cochrane risk of bias tool and Newcastle–Ottawa Scale. Statistical analysis of the data was conducted using R software. PROSPERO registration: CRD42023404151.
Results
A total of 40,087 studies were found through a literature search, of which 22 studies were identified as eligible, involving 612,823 participants, for the meta-analysis. The overall pooled effect estimate for CVD outcome with metformin treatment was found to be a Risk Ratio (RR) of 0.88 (95% CI:0.76-1.03). The pooled effect estimate indicated a significant reduction in CVD-related mortality with metformin treatment, with an RR of 0.75 (95% CI: 0.60-0.93).
Conclusions
This study provides evidence that metformin treatment may not have a significant effect on composite CVD outcomes or individual outcomes such as stroke, MI, HF, and MACE. However, we observed a potential reduction in CVD mortality with metformin use.

Keywords:

Cardiovascular diseases, Diabetes mellitus, Heart failure, Metformin, Myocardial Infarction, Stroke, Angina pectoris, Evidence synthesis, Prevention, Heart attack

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How to Cite

Shabil, M., Bushi, G., Yadav, A., Ahmed, M., Kishore, J., Lekamwasam, S., & Joshi, A. (2023). Effect of metformin on cardiovascular outcomes: a systematic review and meta-analysis of observational studies and RCTs. The Evidence, 1(1), 23–34. https://doi.org/10.61505/evidence.2023.1.1.3

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