. 2020 Oct 2;99(40):e22524. doi: 10.1097/MD.0000000000022524
Copyright © 2020 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 2.
The risk of bias assessment of the included studies.