Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2016 Jun 21;11:777–786. doi: 10.2147/CIA.S105505

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© 2016 Tan et al. This work is published and licensed by Dove Medical Press Limited

The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License (http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed.

PMC Copyright notice

Risk of bias graph.

Notes: (A) Each risk of bias item for each included study. (B) The overall risk of bias is relatively low. “+” indicates yes; “?” indicates not clear.