My sis could never adjust to the CPAP, so she stopped using it. She was in the hospital for nose surgery and the O2 completely eliminated the sleep apnea. It took awhile and some tests before the insurance company got on board with that, but they provided her a refurbished model and she's been using that for 3 years.
She has since lost more than 60 lbs, and while she has more to go, it seems that the sleep apnea has actually stopped now. They are going to do testing this winter and if that is the case, she won't need the refurbished unit any longer either.