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.
Long-term oxygen therapy in Medical Research Council and National Institutes of Health controlled trials in men aged < 70 years, examining the fraction of subjects surviving compared to the time from randomization or duration of treatment. COT = continuous oxygen therapy3; MRC = Medical Research Council4; NOT = nocturnal oxygen therapy.3
