The review addressed a well-defined question in terms of participants, interventions, study design and relevant outcomes. Relevant databases were searched, but only two databases were used when a more extensive search may have been more effective. It was unclear whether there were restrictions on language and publication status. Publication bias was not assessed due to the small number of studies. Study quality was assessed, but the reporting was not comprehensive. The initial study selection process was conducted by only one reviewer and it was not clear whether efforts were made to reduce error and bias in other aspects of the review process.
Some relevant study details were reported but, for example, little detail was provided on the age and gender of patients, which would have been relevant for this study. Statistical heterogeneity was assessed. There was evidence for heterogeneity with one outcome. The statistical method used for the meta-analysis of the RCTs seemed appropriate. No sensitivity analyses were performed, yet the authors concluded that metformin was not indicated for prophylaxis but was following weight gain.
Potential limitations in the review process and uncertain study quality make the extent to which the authors’ conclusions are reliable unclear.