What Is the 4 Hour Rule for CPAP?
This page is general information. It is not medical or insurance advice. Coverage rules change, and your plan decides what it pays. Check with your plan and your clinician.
The 4 hour rule comes from Medicare. To keep paying for your CPAP after the first three months, Medicare wants proof that you used it at least 4 hours a night on 70 percent of nights during any 30 days in a row in those first three months. Your clinician also has to see you and note that the therapy is helping. Many private plans have similar rules, so ask yours.
At a glance.
- Medicare covers a 12 week trial of CPAP for obstructive sleep apnea.
- Use must reach 4 hours a night on 70 percent of nights in a 30 day stretch.
- Your clinician must re-check you between day 31 and day 91.
- Miss it and you can qualify again, but it takes a new visit and a new sleep study in a lab.
Where the Rule Comes From
Medicare.gov says Medicare covers a 12 week trial of CPAP therapy if you have been diagnosed with obstructive sleep apnea. It says Medicare may keep covering it if you meet with your provider in person and they write in your record that you meet certain conditions and the therapy is helping.
The exact conditions are in a Medicare coverage document for these devices, number L33718. That document defines the use requirement as 4 hours or more per night on 70 percent of nights during a consecutive 30 day period, any time in the first three months.
What 70 Percent of 30 Nights Looks Like
Seventy percent of 30 nights is 21 nights. So in some 30 day stretch, you need at least 21 nights with 4 or more hours of use. You can have a few bad nights and still pass. You cannot skip a week here and a week there and expect to make it.
The 30 days can be any 30 days in a row inside the first three months. If your first few weeks are rough, you still have time. Starting strong is easier, though.
How Anyone Knows How Long You Used It
Medicare’s coverage document asks for objective proof of use, meaning data from the machine rather than your memory. Most modern machines record when they are running. Your equipment supplier or clinician can usually read that record. Ask them how they get your data and how you can see it too, so there are no surprises at the follow up visit.
The Follow Up Visit
The coverage document says the clinician must re-evaluate you no sooner than day 31 and no later than day 91 after you start. At that visit they look at your use data and ask how you feel. Your record needs to show the treatment is helping. Book this visit early. A missed visit can cause a problem even if you used the machine every night.
What If You Do Not Meet It
The coverage document says that if the 12 week trial fails, you can qualify again. You need an in person visit with your clinician to work out why it did not work, and a repeat sleep study done in a sleep lab. That is more time and more cost, so it is worth asking for help early instead of hoping it gets easier on its own.
If CPAP itself is the problem, other treatments exist. Our guide to CPAP alternatives walks through them.
What Medicare Patients Pay
Medicare.gov says that after you meet the Part B deductible, you pay 20 percent of the Medicare approved amount for the machine rental and supplies. Medicare pays the supplier for rental, and after 13 months of continuous rental you own the machine. Medicare.gov also says the supplier must be enrolled in Medicare. If they accept assignment, they can only charge you the coinsurance and deductible on the approved amount.
Tips to Hit 4 Hours
- Put it on every time you sleep, including naps. Cleveland Clinic says CPAP only works if you use it every time you sleep.
- Fix discomfort fast. A dry nose, a leaky mask or sore skin can usually be changed. Our post on CPAP side effects covers the usual fixes.
- Put the mask back on if you wake up in the night and find it off.
- Check your data weekly so you know where you stand before the follow up visit.
- Call early. Your clinician would rather hear about a problem in week two than week ten.
Private Insurance and Medicaid
This page is about Medicare because its rule is public. Private plans and state Medicaid programs set their own terms, and many check CPAP use in a similar way. Call the number on your card and ask two questions. Do you require a certain amount of CPAP use to keep paying. And how do you check it.
Need a Clinician for the Follow Up?
If you do not have a sleep clinician to see in that day 31 to 91 window, our directory lists sleep apnea providers by state and city. Ask whether they accept Medicare before you book. A listing is not a referral.
Common Questions
What is the 4 hour rule for CPAP?
It is a Medicare rule. To keep covering CPAP after the 12 week trial, Medicare wants proof of use for 4 or more hours a night on 70 percent of nights during a 30 day stretch in the first three months, plus a follow up visit showing the therapy helps.
How many nights do I need to use CPAP to meet the rule?
At least 21 nights out of 30 in a row, with 4 or more hours each of those nights. The 30 days can be any stretch in the first three months.
What happens if I fail the CPAP trial?
Medicare’s coverage document says you can qualify again after an in person visit to find out why it failed and a repeat sleep study in a sleep lab.
Does private insurance have a 4 hour rule too?
Many plans check CPAP use, but each one sets its own terms. Call the number on your insurance card and ask what they require.
Keep Reading
- CPAP side effects and the usual fixes
- CPAP alternatives
- Does insurance cover a sleep study
- Find a provider with our lookup
- Sleep apnea providers in Ohio
- Sleep apnea providers in Michigan
Sources
- Medicare.gov, Continuous Positive Airway Pressure Devices
- CMS, Positive Airway Pressure Devices for the Treatment of Obstructive Sleep Apnea (L33718)
- Cleveland Clinic, CPAP Machine
NightWells publishes information, not medical advice. Nothing here replaces being seen by a clinician who can examine you.
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