A meta-analysis comparing metformin with insulin in women with gestational diabetes suggests that there is no clinically relevant difference in efficacy or safety between the two agents, and that the former may even be superior.
The authors, from Peking University, Beijing, China, identified eight randomised controlled trials, in which a total of 1592 participants with gestational diabetes were enrolled. Pooled analysis showed no difference between the agents in terms of neonatal outcomes such as respiratory distress syndrome, jaundice or perinatal death. Metformin was associated with a reduced risk of pregnancy-induced hypertension (risk ratio [RR], 0.54; 95% confidence interval [CI], 0.31–0.91], and there were trends towards reduced risk of neonatal hypoglycaemia (RR, 0.80; 95% CI, 0.62–1.02) and large-for-gestational age infants (RR, 0.77; 95% CI, 0.55–1.08).
The 2015 NICE NG3 guideline on gestational diabetes recommends metformin as the first-line treatment in women who fail to achieve glycaemic control with diet and exercise alone, although metformin’s Summary of Product Characteristics states that it should not be used, advising instead that insulin should be used in order to achieve tighter control. The current findings, which are in line with previous data published in the BMJ, support the NICE recommendation and indicate that metformin is associated with better pregnancy outcomes than insulin.
The study can be read in full here.
