Effect of metformin on the clinical outcomes of stroke in patients with diabetes: a systematic review and meta-analysis

Objectives Stroke is a major cause of death and disability globally, especially among diabetic patients. In this study, we aim to scrutinise the effects of metformin on the clinical outcomes of stroke in diabetic patients.Design This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.Data sources PubMed, Embase and Web of Science databases were searched between their inception and 5 December 2023.Eligibility criteria for selecting studies Studies investigating the effect of metformin on the clinical outcomes of stroke in patients with diabetes were included.Data extraction and synthesis The effect of metformin on the clinical outcomes of stroke in patients with diabetes was identified using combined ORs and 95% CIs.Results A total of 11 studies involving 18 525 participants were included in this review. Pooled analysis has demonstrated that prestroke metformin use could reduce the probability of poor course after stroke by 34% in diabetes mellitus (DM) patients (OR=0.66, 95% CI: 0.61 to 0.72) and reduce the probability of death by 43% (OR=0.57, 95% CI: 0.51 to 0.64).Conclusions Prestroke metformin use is beneficial for the improvement of clinical outcomes in patients who had a stroke with DM, although the potential bias should be carefully considered.PROSPERO registration number CRD42024496056.