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

. 2018 Sep 5;12(6):2136–2143. doi: 10.1177/1557988318797409

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

© The Author(s) 2018

This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License (http://www.creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/open-access-at-sage).

PMC Copyright notice

Figure 2. — Methodological quality assessment of the risk of bias for each included study. = low risk of bias; = unclear risk of bias; = high risk of bias.

Inline graphic — Methodological quality assessment of the risk of bias for each included study. = low risk of bias; = unclear risk of bias; = high risk of bias.