An official website of the United States government
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.
Study CONSORT flow chart, February 2004–February 2010. F1, F6, and F12 stand for 1-month follow-up, 6-month follow-up, and 12-month follow-up, respectively.