. 2016 Aug 7;95(31):e4424. doi: 10.1097/MD.0000000000004424
Copyright © 2016 the Author(s). Published by Wolters Kluwer Health, Inc. All rights reserved.
This is an open access article distributed under the Creative Commons Attribution License 4.0, 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.
Flowchart showing the identification and selection of studies.