Table A1.

Amendments (and rationale) to the protocol of the present systematic review.

Original Protocol	Amendments (A) and Rationale (R)
Section: The primary systematic literature search on electronic databases. Text: Two independent reviewers (FE-L and JC-M) will perform a primary electronic search in PubMed, Scopus and Web of Science on 9 January 2018	A: The search will be updated to include works published up to 15 June 2019. R: Due to budget restrictions to cover the publication fee, it was decided to postpone the preparation of this work.
Section: Exclusion criteria Text: Studies published more than 10 years ago (i.e., before 2008).	A: Studies published before 1994. R: The decision lacked of a strong rationale and it was too restrictive. Given that studies that used the CDC−1994, Canadian Consensus Criteria, London Criteria, International Consensus Criteria or Institute of Medicine criteria will be considered, we will search for the literature that has been published from 1994, when the CDC−1994 were launched.

Notes. The original protocol is accessible in the following link: https://bmjopen.bmj.com/content/8/9/e020817.long. The table shows the amendments to the Protocol manuscript by Estévez-López et al. in BMJ Open.