Insurance, Medicare and cost
Medicare CPAP Compliance: The 4 Hours, 70% of Nights Rule
To keep Medicare paying for your CPAP after the first 3 months, you must use it 4 hours or more per night on at least 70% of nights during a consecutive 30 day period, and see your clinician between day 31 and day 91 to document that therapy is helping. That means at least 21 nights out of a 30 night window.
The adherence rule
CMS policy L33718 defines adherence as use of PAP 4 hours or more per night on 70% of nights during a consecutive 30 day period anytime during the first three months of initial usage.
Seventy percent of 30 nights is 21 nights. A night with 3 hours 50 minutes does not count. You only need one qualifying 30 day window in the first 90 days, not 90 straight days.
The face to face re-evaluation
The LCD requires a clinical re-evaluation no sooner than the 31st day and no later than the 91st day after starting therapy. At that visit your treating practitioner documents that your symptoms improved and reviews the objective usage data from your machine.
Book this appointment early. Missing the window can stop coverage even if your usage was perfect.
How your usage is tracked
Most machines send usage data over a cellular modem to your supplier and clinician. If yours does not, the data is on the SD card or in the machine's memory and can be downloaded.
Keep the machine plugged in and the modem on so data uploads. Airplane mode stops wireless transfer; ResMed says data will only be transferred if a wireless connection is available.
Tips to hit 21 good nights
Start early in the evening, not at the last minute. If you take the mask off in the night, put it back on. Use CPAP for naps.
Fix problems fast: mask leaks, dry mouth and claustrophobia are all solvable, and your supplier is expected to help in the first weeks. Check your app or machine screen each morning to see your hours.
If you do not meet the rule
If you fail the initial trial, Medicare will deny continued coverage. To requalify, the LCD requires an in-person re-evaluation to determine why therapy failed and a repeat sleep test in a facility (Type I study).
Talk with your clinician before you give up. A different mask, comfort settings, or in some cases a different therapy may help.
Checklist
- Note your start date.
- Book the follow-up visit for between day 31 and day 91.
- Leave the modem on and the machine plugged in.
- Check your hours every morning.
- Count your 4+ hour nights toward 21 out of 30.
- Call your supplier about any mask problem in week one.
Frequently asked questions
What is Medicare's CPAP compliance requirement?
Using CPAP 4 hours or more per night on 70% of nights during a consecutive 30 day period in the first 3 months, plus a clinical re-evaluation between day 31 and day 91 documenting that you benefit.
Do naps count toward CPAP compliance?
Usage is counted by session data your machine records. Short naps add hours on the day they happen, but what matters for the rule is reaching 4 hours of use in each counted day.
Does my private insurance have the same rule?
Many private plans use the same or a similar 4 hours on 70% of nights rule, but not all. Ask your plan or supplier for the exact rule and deadline.
What happens if I miss the day 31 to 91 visit?
Without that documented re-evaluation, Medicare coverage after the first 3 months can be denied even if your usage was good. Contact your clinician to see what can be arranged.
Is CPAP compliance still required after the first 90 days?
For Medicare, the formal adherence test is in the initial 3 months. Your supplier may still review usage, and ongoing use is what actually treats your sleep apnea.
Sources
Last reviewed October 11, 2026. How we research · Report an error