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.
Propensity score density graph in the unmatched (A) and matched (B) cystic fibrosis (purple) and non-cystic fibrosis (green) cohorts, depicting similar propensity score density in the two cohorts in the matched groups (B). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
