Searching other resources. It is also planned to manually retrieve articles considered relevant in non-indexed literature in the cited databases, such as dissertations or theses, using the Gray Matters-Canada‘s Drug and Health Technology Agency (CADTH) gray literature registry (https://www.cadth.ca ) and Grey Source (http://greynet.org/greysourceindex.html). In addition, it was planned to maintain contact with relevant people and organizations to obtain information on unpublished or ongoing studies. We also hand-searched the reference lists of included studies and any current relevant systematic reviews