FIGURE 2.
The Quality in Prognosis Study (QUIPS) risk of bias tool assessment of included studies. Green indicates low risk of bias, amber indicates a moderate risk and red indicates a high risk of bias.
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.