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Association of metformin monotherapy or combined therapy with cardiovascular risks in patients with type 2 diabetes mellitus

Tian Li, R. Providência, Nan Mu, Yue Yin, Mai Chen, Yishi Wang, Manling Liu, Lu Yu et al.

Cardiovascular Diabetology, 2021

91 citations

Abstract

Background Metformin is a first-line drug in type 2 diabetes mellitus (T2DM) treatment, yet whether metformin may increase all-cause or cardiovascular mortality of T2DM patients remains inconclusive. Methods We searched PubMed and Embase for data extracted from inception to July 14, 2020, with a registration in PROSPERO (CRD42020177283). This study included randomized controlled trials (RCT) assessing the cardiovascular effects of metformin for T2DM. This study is followed by PRISMA and Cochrane guideline. Risk ratio (RR) with 95% CI was pooled across trials by a random-effects model. Primary outcomes include all-cause mortality and cardiovascular mortality. Results We identified 29 studies that randomly assigned patients with 371 all-cause and 227 cardiovascular death events. Compared with untreated T2DM patients, metformin-treated patients was not associated with lower risk of all-cause mortality (RR: 0.98; 95%CI: 0.69–1.38; P = 0.90), cardiovascular mortality (RR: 1.13; 95% CI: 0.60, 2.15; P = 0.70), macrovascular events (RR: 0.87; 95%CI: 0.70–1.07; P = 0.19), heart failure (RR: 1.02; 95% CI:0.61–1.71; P = 0.95), and microvascular events (RR: 0.78; 95% CI:0.54–1.13; P = 0.19). Combination of metformin with another hypoglycemic drug was associated with higher risk of all-cause mortality (RR: 1.49; 95% CI: 1.02, 2.16) and cardiovascular mortality (RR: 2.21; 95% CI: 1.22, 4.00) compared with hypoglycemic drug regimens with no metformin. Conclusion The combination of…

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