The review addressed a clear question and was supported by appropriate inclusion criteria. Attempts to identify relevant studies were undertaken by searching electronic databases and other methods, although the restriction to including only studies published in English meant that relevant studies may have been missed (and the review may have been subject to publication or language bias). Suitable methods were employed to reduce the risks of reviewer error and bias for all relevant review processes.
Trial quality was assessed and was used to interpret the results of the review. Sufficient trial details were provided. Appropriate methods were used to pool data and evaluate heterogeneity.
Despite the fact that relevant studies may have been missed, the review was otherwise generally well conducted, so the authors' conclusions appear likely to be reliable.