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

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 Conclusions Metformin with insulin has the potential to retard the progression of atherosclerosis and provides better metabolic control in patients with T1DM, and thus, providing a potential th…