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.
Note: RAS=resistance associated substitution. All heterogeneity tests also adjusted for the interaction between strategy and fixed-duration vs variable-duration randomisation. Some confidence intervals and heterogeneity p-values could not be estimated due to perfect prediction.
