Inclusion criteria for the review were clearly defined. Several relevant databases were searched for articles in any language. Publication bias was not assessed, although unpublished data were sought. Attempts were made to reduce error and bias throughout the review.
Quality assessment was undertaken using a valid tool; all included trials were deemed at a low risk of bias. Trials were synthesised narratively, which seemed appropriate given the type of data. The authors noted that caution was warranted when interpreting their results as some trials were not blinded, had no active comparator, and there were limitations with certain outcomes.
The review was generally well conducted. The authors’ conclusions reflect the limitations of the evidence presented and seem appropriate.