The review question was clear in terms of the intervention, outcome and participants of interest. Two electronic databases were searched, but the search strategy was not provided and it was unclear whether any language restrictions were applied. Unpublished data were sought from one source, but no assessment of potential publication bias was attempted. However, formal publication assessments do have limitations when the number of studies is small. It was not stated how the studies were selected or the data extracted, so these processes could not be assessed for the presence of bias.
A pooled analysis of the four trials was presented. This included three different study designs, and heterogeneous patient populations and interventions. Despite pooling these four studies statistically, no formal attempts were made to investigate any statistical heterogeneity that might be present. The author acknowledged some of the differences between the studies included in the pooled analysis, and the directions of the treatment effects were consistent between the studies.
The author's conclusions appeared to follow from the evidence presented in the individual studies. However, the search was limited and there was no quality assessment of the individual studies. The studies included in the pooled analysis appeared to be heterogeneous, particularly in terms of study designs and outcomes reported. Reducing the results to a single summary estimate by pooling was inappropriate, and the conclusions should be viewed with due caution