Search strategy and identification of the studies

PubMed, Scopus, Web of Science, Cochrane Library, Virtual Health Library (LILACS) databases were consulted, and articles published before July 30th, 2019 were considered for review. The search of the literature was applied in Grey literature through the OpenGrey site (http://www.opengrey.eu), and references of included studies were also searched to identify other studies that might have been missed in the initial electronic search. No language or date restrictions were applied; all references were managed using Mendeley software. The selection process is described in Figure 1.

The keywords used were selected from Medical Subject Headings (MeSH) specified by the U.S. National Library of Medicine and from Health Sciences Descriptors (DeCS). Besides these, MeSH synonyms and free terms were also included. The terms were combined through boolean operators to improve the search; all combinations of terms have been collated in Table 1.