The review question was clear and was supported by appropriate inclusion criteria for intervention, comparison, participants and outcomes, but broad for study design. The literature search was limited to one database; it was unclear whether any language restrictions were applied or whether attempts were made to locate unpublished data, so potentially relevant studies may have been missed. Study selection and data extraction were performed in duplicate, reducing the potential for error and bias.
Study quality did not appear to have been assessed, so the robustness of the findings was unclear. Patient and study details were lacking, so it was unclear whether pooling of the results was appropriate. Only a small number of studies were included and there was some evidence of statistical heterogeneity.
The authors’ conclusions reflected the evidence available and their recommendation for further research seemed appropriate. However, as the evidence base was of a small number of studies of unknown quality and there was potential for some bias in the review, the authors' conclusions regarding safety and compliance should be interpreted with caution.