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.
Data are expressed as median (interquartile range) or frequency (n). Significant differences were determined using the Mann-Whitney U-test. PSM: Propensity score matching; AU: arbitrary units.
