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Vascular and metabolic effects of metformin added to insulin therapy in patients with type 1 diabetes: A systematic review and meta-analysis

Liu YS, Chen CN, Chen ZG, Peng Y, Lin XP, Xu LL

Diabetes/metabolism research and reviews, 2020

1,540 participants

Abstract

BACKGROUND: The incidence of type 1 diabetes mellitus (T1DM) is increasing among youth worldwide, translating to an increased risk ofearly-onset cardiovascular disease (CVD). Mounting studies have shown that metformin may reduce maximal carotidintima-media thickness (cIMT), improve insulin resistance and metabolic control in subjects with T1DM, and thus, may extend cardioprotective benefits. This systematic review and meta-analysis was performed to assess the efficacy and safety of metformin added to insulin therapy on reducing CVD risks and improving metabolism in T1DM.

METHODS: PubMed, EMBASE, and the Cochrane Library were systematically searched for randomized controlled trials (RCTs) that compared metformin and insulin combination (duration ≥3 months) to insulin treatment alone in T1DM. Data were expressed as weighted/standardized mean differences (MDs/SMDs) for continuous outcomes and risk ratios (RRs) for dichotomous outcomes, along with 95% confidence intervals (CIs). The Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to evaluate the overall certainty of the evidence.

RESULTS: Nineteen RCTs (n = 1540) met the eligibility criteria. Metformin treatment significantly reduced carotid artery intima-media thickness (MD -0.06 mm [95% CI -0.88, -0.28], P < .001). Though no significant difference was found in insulin sensitivity (SMD 2.21 [95% CI -1.88, 6.29], P = .29), the total daily insulin dosage (SMD -0.81 [95% CI -1.25, -0.36], P <…

How strong is the evidence?

Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 1,540 participants or records.

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