Inclusion criteria for the review were clearly defined and several relevant databases were searched. There was the potential for both language and publication bias, as only published English language articles were included; publication bias was not assessed. Attempts were made to minimise error and bias in the process of study selection and data extraction, but the same could not be assumed for quality assessment.
Quality assessment was undertaken using a standard checklist, which was appropriate. The RCTs were combined using fixed-effects meta-analysis which appeared appropriate, given the large sample size, lack of heterogeneity and high quality of the included trials.
Despite the potential for selection biases, the review was generally well conducted. The authors’ conclusions are based on the evidence and appear appropriate.