Efficacy and safety of metformin compared to insulin in gestational diabetes: a systemic review and meta-analysis of Chinese randomized controlled trials

Background Metformin is widely used for the treatment of gestational diabetes. Although some meta-analyses are conducted on the efficacy and safety of metformin, none of them are focused on the Chinese population. The efficacy and safety of metformin in the Chinese GDM population are unknown. Aim The study aimed to compare metformin to insulin regarding the safety and efficacy in Chinese GDM patients using randomized controlled trials (RCTs) conducted in China. Method Chinese databases (Wanfang, CNKI, VIP, and CBM), PubMed, Embase, Cochrane library, and Scopus were searched for RCTs. The last search date was October 18, 2021. Results Fifty RCTs (4663 patients) were included in this study after screening. Six outcomes were analyzed. In the main analysis, metformin had lower risk of respiratory distress syndrome (RDS, OR, 0.28; 95% CI 0.16-0.51; P < 0.0001), premature birth (OR, 0.42; 95% CI 0.21-0.85, P = 0.02), and neonatal hypoglycemia (OR, 0.34; 95% CI 0.24-0.48; P < 0.00001) compared to insulin. Moreover, the metformin group is better than the insulin group concerning all other outcomes such as maternal glycemic control and glycated hemoglobin. Subgroup analysis confirmed that metformin has better outcomes than all types of insulin except for RDS, premature birth, 2 h postprandial blood glucose, and glycated hemoglobin. Conclusion Metformin is considered to be a safe and effective alternative to insulin for the management of GDM if patients refuse insulin due to any reasons in China.

Automated summary

This study aimed to compare the safety and efficacy of metformin and insulin in Chinese gestational diabetes mellitus (GDM) patients. The results showed that metformin had lower risks of respiratory distress syndrome, premature birth, and neonatal hypoglycemia compared to insulin. Furthermore, metformin showed better outcomes in other aspects such as maternal glycemic control and glycated hemoglobin.