. 2018 Dec 14;97(50):e13593. doi: 10.1097/MD.0000000000013593
Copyright © 2018 the Author(s). Published by Wolters Kluwer Health, Inc.
This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. http://creativecommons.org/licenses/by/4.0
Figure 1.
PRISMA diagram of the process of selecting relevant studies.