The review addressed a clear question supported by appropriate eligibility criteria. Three electronic databases were searched to identify relevant studies. It was unclear whether any language restrictions were used and whether unpublished studies were sought specifically, so some relevant trials may have been missed. It appeared that suitable methods were used to minimise risks of reviewer error and bias during the various stages of the review.
The authors reported that they extracted mean differences and risk ratios, but these data were not provided and a narrative synthesis was performed. A quality assessment was carried out and the authors stated that methodologies were often suboptimal; this conclusion appeared somewhat at odds with the assessment results which seemed to indicate that studies were generally of good quality (albeit with small sample sizes). Actual trial results were presented only for the primary outcome.
The authors' conclusions appeared to reflect the evidence presented and are likely to be reliable.