The authors follow established review procedures and conduct an extensive search that includes both published and unpublished literature. A particular strength to the review is the clear and thorough presentation of study characteristics and findings. Given the heterogeneity of included studies, the authors synthesise studies narratively. The review has some limitations. Firstly, the authors limited eligible studies to those reported in French or English. Secondly, they use of the STROBE and CONSORT checklists to assess quality of reporting rather than risk of bias. Nevertheless, the review still provides a fairly thorough and transparent critical appraisal of the evidence.