Home Sleep Testing - Provider FAQs

HST Background Eligibility and Screening HST vs. PSG
Portable Monitors Equipment Specifics The Process
Managing the Patient The Rules Insurance Information

HST Background

What does the Medicare National Coverage Determination (NCD) state about home sleep testing?

Previously, home sleep testing (HST) was considered an unproven technology and most third party payors would not cover treatment with continuous positive airway pressure (CPAP) when the diagnosis was made using a HST device, nor, in most cases, pay for the testing itself.

In March, 2008, Centers for Medicare and Medicaid Services (CMS) issued a National Coverage Determination (NCD) policy stating the evidence supported use of HST to establish the diagnosis of obstructive sleep apnea (OSA) in some patients and they would cover CPAP treatment based on that diagnosis.

In addition, payment by Medicare for CPAP for longer than 3 months requires documentation of improvement of the patient’s OSA. This mandates demonstration of effectiveness of treatment. In the NCD, CMS left development of guidelines for selection of patients and demonstration of improvement to the regional carriers.

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Why did Medicare feel this was a good thing for patients?

Medicare placed new emphasis on making sure patients benefit from CPAP therapy. They felt there was sufficient data that the method of diagnosing OSA in certain patients was comparable and the method of diagnosis did not influence response to therapy. After the diagnosis of OSA is made, they emphasized the need to monitor and demonstrate that patients are using CPAP and benefiting from treatment.

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What proof is required to demonstrate compliance and benefit from CPAP treatment?

At this time, there is no definition as to what will constitute compliance or treatment benefit. The NCD has left that determination to local carriers.

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Eligibility and Screening

Who ultimately determines if a patient can be studied using HST?

HST should be utilized only as part of a comprehensive sleep evaluation. Sleep HealthCenters (SHC) can conduct an evaluation to determine if the patient is appropriate for HST. The referring provider can order the test if they determine the patient meets criteria for HST.

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Who is eligible for HST?

The answer to this question is insurance provider-dependent. NHIC, the regional Medicare carrier for Massachusetts Part B (IDTFs and Physicians), issued a Local Coverage Determination (LCD) in March 2008, limiting the diagnosis of OSA to the in-laboratory setting. Aetna, Fallon and NHP have issued guidelines allowing HST for the diagnosis of OSA. In the next 6 months, other groups are likely to follow the NCD, including NHIC.

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What type of patient is a candidate for HST? Who would we recommend to have HST?

The American Academy of Sleep Medicine (AASM) has published suggested guidelines for the use of HST in the diagnosis of OSA. They recommend that HST be used only in the context of a comprehensive sleep evaluation and for the following patients:

  1. Patients with a high pre-test probability of moderate to severe OSA.
  2. Patients with no significant co-morbid medical condition. Examples of co-morbid conditions include moderate-severe pulmonary diseases (cystic fibrosis, pulmonary fibrosis, active asthma, COPD), congestive heart failure and neuromuscular diseases (ALS, multiple sclerosis, Parkinson’s disease).
  3. Patients suspected of having no co-morbid sleep disorder other than OSA.
  4. Patients unable to be studied in a sleep laboratory.
  5. To monitor response to non-CPAP treatments after the diagnosis has already been made.

The AASM recommended that HST is not appropriate for general screening of asymptomatic patients.

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Is there a screening tool for the referring provider to use to determine who is a good candidate for HST?

A useful formula for estimating patients at high risk for moderate to severe OSA:
Patients at high risk for moderate to severe OSA have symptoms of OSA, excessive daytime sleepiness and an Adjusted Neck Circumference > 43 cm (17 inches)

  1. Symptoms of OSA = snoring, stopping breathing episodes or complaints of daytime sleepiness 
  2. Presence of excessive daytime sleepiness = Epworth sleepiness scale >10
  3. Adjusted neck circumference = neck circumference + 4 cm (if hypertension present) + 3 cm (if habitual snorer) + 3 cm (if reported to choke or gasp most nights)

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What is adjusted neck circumference?

It is a formula used to predict the likelihood of having moderate to severe OSA. It incorporates several of the most common risk factors for OSA, including neck size (a marker of obesity), the symptoms of snoring and gasping at night and the presence of hypertension.

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How do you get the Epworth sleepiness scale score?

The Epworth Sleepiness Scale and answer key is below. Circle answers and tally up numbers to get score.

Epworth Sleepiness Scale
In the last 30 days, how likely are you to doze off or fall asleep in the following situations (in contrast to feeling just tired)? High Chance  Moderate Chance Slight Chance No Chance
 1. Sitting and Reading  3  2  1  0
 2. Watching TV  3  2  1  0
 3. Sitting inactive in a public place (e.g. theater, meeting)  3  2  1  0
 4. As a passenger in a car for an hour without a break  3  2  1  0
 5. Lying down to rest in the afternoon   3  2  1  0
 6. Sitting and talking to someone  3  2  1  0
 7. Sitting quietly after lunch (when you've had no alcohol)  3  2  1  0
 8. In the car while stopped for a few minutes in traffic  3  2  1  0
Total Score
Answer Key

 1-6
You are getting enough sleep

7-8
Your score is average

9 or more
Seek the advice of a sleep specialist

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HST vs. PSG

Is an HST better than an in-lab PSG?

In patients with a high pre-test likelihood of moderate to severe OSA, HST is comparable to in-laboratory PSG. HST tends to underestimate severity of OSA compared to in-laboratory PSG but has similar likelihood ratios for detecting the presence of OSA. 

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How does HST differ from an in-lab test?

HST is used only to look for obstructive sleep apnea. Only 4-5 channels of physiologic data regarding respiration are obtained, as opposed to 14 channels during in-lab polysomnography.

Information on sleep stages and EEG is not obtained with HST. As a result, HST may underestimate the severity of OSA. If the HST is negative in a patient suspected of having OSA, the patient should have an in-lab PSG for confirmation. 

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If using HST, how many hours of sleep do you need to get accurate results?

You cannot determine amount of sleep with an HST. At least 2 hours of recording time is needed to make a diagnosis of OSA. Because of these limitations, HST should be performed and interpreted by someone trained and competent in using the devices. 

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Portable Monitors

What do levels 1, 2, 3 and 4 mean with regard to sleep studies?

These describe the different types of sleep monitors and the level is determined by the number of physiologic channels measured.

Level 1: 

Full attended in-laboratory polysomnography

> 7 channels with sleep staging

Level 2:

Full unattended portable polysomnography

> 7 channels with sleep staging

Level 3:

Portable, unattended sleep apnea monitors (AASM recommendation for HST)

> 4 channels, no sleep staging

Level 4:

Limited unattended monitors

1-3 channels, no sleep staging

 Note: Level 3 and Level 4 devices do not measure sleep time.

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How accurate is the data?

A recent CMS-commissioned Agency for Health Research and Quality (AHRQ) report found that portable monitors were able to predict an AHI suggestive of OSA with high positive likelihood ratios and low negative likelihood ratios. HST devices tend to under estimate the AHI because they do not measure sleep time but rather recording time.

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What do the portable monitors measure exactly?

Depending on the level and the specific device, they measure some combination of airflow, respiratory effort, oximetry, heart rate and/or snoring.

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What portable monitors are on the market? How do they differ?

There are a wide variety of devices on the market, however, there is no data suggesting one portable monitor is superior to another. They differ by the number and type of physiologic channels measured.

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Equipment Specifics

For HST, what level of sleep studies will SHC conduct?

For HST, SHC will use the following, as recommended by the AASM:
Level 3: Portable, unattended sleep apnea monitors
> 4 channels, no sleep staging 

Which portable monitor is SHC using?

A Stardust® II Sleep Recorder from Respironics, Inc.

Stardust is a Level 3 device that meets all the specifications recommended by the American Academy of Sleep Medicine Clinical Guideline for the Use of Portable Monitors.

We have been using Stardust for many years and are quite familiar with its use and limitations. It is already fully compatible with our other sleep diagnostic equipment and software and we can use the same report templates we currently use with little modification. The cost to us of using the device is lower than other devices.

Additionally, our patients have found it easy to use.

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What does the Stardust measure?

The Stardust has 4 channels:

  1. SP02 (oxygen saturation)
  2. Heart Rate
  3. Air Flow
  4. Effort

The Stardust also records: 

  1. Snoring
  2. Position

The Stardust does not record EEG.

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The Process

What is the process for studying and treating a patient using HST? Timing?

Ideally, patients are referred for an evaluation by a sleep specialist who can decide if a patient is appropriate for HST. If appropriate, the patient is given a device and instructed how to put it on by a sleep technologist. The patient returns or mails the device back to the center the following day. The study is scored and interpreted by a sleep specialist. The patient returns the following week to see the sleep specialist, who reviews the result of the study with the patient and selects appropriate treatment.

If the referring physician thinks the patient is appropriate for HST but wants SHC to manage the patient, they can send the patient for a 24-hour turnaround service. The patient picks up the device in the afternoon/evening with instruction on its use from the sleep technologist. The patient returns to the clinic with the device the next day and during the same visit the study is scored and interpreted, the sleep specialist reviews the study with the patient, the type of treatment is selected and treatment is initiated, all in the same visit.

If the referring physician thinks the patient is appropriate for HST and wants to manage the patient themselves, they can order the test and receive back a report interpreted by a sleep specialist. SHC will be able to assist with treatment if desired by the referring physician.

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Do we have the capability to set up patients in their home?

We instruct patients how to use the devices in our facilities and they take them home. Only patients unable to come to a center are set up at home.

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What is our ability to intervene or support patients remotely?

Patients are given a 24-hour number to call if they are having problems with their devices.

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What locations currently offer HST with 24-hour turnaround?

Brighton, Framingham, Medford and Weymouth, Massachusetts.

Managing the Patient

If a patient has a “positive” HST, will the patient then need a full night titration or can they just come in for a setup?

The patient will either need a titration study to determine the optimal CPAP setting or have the optimal pressure determined using an auto titrating CPAP device in their home. If the patient is using an auto titrating device at home, they will return the machine after one week and convert to CPAP machine.

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What happens if the HST shows a negative result, but the patient continues to have symptoms of a sleep disorder?

Because HST may underestimate OSA compared to in-laboratory PSG, a negative HST result in a patient with a high pretest suspicion for OSA (the type of patient who should be getting HST) should be followed by in-laboratory PSG to confirm the results.

Can the patient receive CPAP during the HST? How is the patient set up on CPAP?

Split night studies cannot be done with HST. If the HST shows the patient has OSA, that patient can either undergo an in-laboratory CPAP titration study or a home CPAP titration using an auto titrating CPAP machine that can be used to determine the optimal CPAP pressure. If the patient is using an auto titrating device at home, they will return the machine after one week and convert to CPAP machine. 

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Who should talk to the patients about the results?

Ideally, the patient should discuss the results with a sleep specialist who is knowledgeable about sleep disorders, HST interpretation and the variety of sleep disorders. All tests should be discussed directly with the patient by a physician.

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How should patients be managed after they have the test?

If the test is positive for OSA the patient should have a comprehensive treatment plan made, including the best method for treating OSA, risk factor modification and improvement in sleep habits. If CPAP is selected as treatment, a compliance program should be developed and implemented. This includes frequent early follow-up to assure proper utilization, improvement in symptoms and resolution of side effects and adverse effects, if any. Ongoing follow-up is necessary to assure long-term compliance with therapy.

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The Rules

What types of companies are allowed to do HST?

There are currently no regulations specifying qualifications of companies doing HST. We recommend using companies associated with an American Academy of Sleep Medicine accredited sleep center to ensure the highest possible quality.

Medicare has stated verbally that they do not want DME companies performing HSTs.

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Do physicians still interpret the results?

Yes. At Sleep HealthCenters, all studies are reviewed by a board-certified sleep specialist. 

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Do the interpreting physicians have to be board certified in sleep?

No. However, at SHC, all studies are reviewed by a board-certified sleep specialist. 

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Insurance Information

What insurances pay for HST studies?

As of 4/21/08:

  • Aetna
  • Fallon (Requires a pre-authorization for CPAP.)
  • Medicare (Medicare has stated that their changes to the use of HST will be retroactive to March 13, 2008. However, we would prefer to wait for the official local coverage determination notice, expected in the summer of 2008. HSTs requested for Medicare should be evaluated on an individual basis.)
  • Neighborhood Health Plan (NHP) (Requires a pre-authorization for a sleep study – HST must be pre-scheduled at least 3 days out; not eligible for 24-hour turnaround or device training directly after clinical evaluation.)  

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