Figure 2.
The methodological quality of the included studies by design.
Abbreviations: CT, clinical trial; P, prospective; R, retrospective; RCT, randomized controlled trial.
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.