Evidence before this study: This section should include a description of all the evidence that the authors considered before undertaking this study. Authors should briefly state: the sources (databases, journal or book reference lists, etc) searched; the criteria used to include or exclude studies (including the exact start and end dates of the search), which should not be limited to English language publications; the search terms used; the quality (risk of bias) of that evidence; and the pooled estimate derived from metaanalysis of the evidence, if appropriate.

Added value of this study: Authors should describe here how their findings add value to the existing evidence.

Implications of all the available evidence: Authors should state the implications for practice or policy and future research of their study combined with existing evidence. Research in context panels should not contain references; key studies mentioned here should be referenced in the main text.