At the 2012 American Thoracic Society Conference in San Francisco in May, Samuel T. Kuna, MD, and Allan I. Pack, MBChB, PhD, both from the University of Pennsylvania School of Medicine, were charged with debating the topic “In Laboratory Polysomnography Is on Life Support: The Future of Sleep Medicine Is Home Sleep Studies.” While a debate over diagnostic choices could have pitted Kuna and Pack on very opposite ends of the spectrum, both instead agreed that the larger question sleep professionals should be concerning themselves with is what these tools mean for the future of sleep medicine and ensuring the best treatment for the patient.
In the debate, Dr Kuna took the pro side of “In Laboratory Polysomnography Is on Life Support: The Future of Sleep Medicine Is Home Sleep Studies.”
Samuel T. Kuna, MD: There are some things we ought to keep in mind as we hold portable monitor testing up to our gold standard, polysomnography. Unlike pulmonary function tests that use calibrated signals, polysomnograms consist mostly of qualitative signals and are scored by pattern recognition. Interpretation of a polysomnogram is much closer to reading a chest x-ray or an electrocardiogram than a pulmonary function test. Compounding this limitation is the lack of one uniformly accepted rule for scoring hypopneas. There are currently three scoring criteria that have been approved by the American Academy of Sleep Medicine. Depending on which criteria are used leads to a significant difference in the apnea/hypopnea index (AHI), the PSG outcome measure used to diagnose sleep apnea. We also have the problems of significant night-to-night variability in the AHI on polysomnography and the lack of association of the AHI on polysomnography with clinical symptoms and outcomes. Finally, the disease severity that we assign to patients based on their polysomnographic results—mild, moderate, and severe—is a consensus statement rather than something that is based on evidence.
However, portable monitor testing has its own limitations. The portable monitors that are used most frequently in clinical practice do not have sleep staging signals to distinguish wakefulness and sleep. These monitors tend to underestimate the AHI that would have been obtained on a simultaneous polysomnogram because the AHI on home sleep testing is calculated on the basis of recording time rather than sleep time.
Portable monitor testing has several other important limitations. There are significant differences among portable monitors, even those within the same class. They are not able to diagnose sleep disorders other than sleep apnea. There is an inability of some of the monitors to differentiate obstructive versus central apnea with Cheyne-Stokes respiration. Most validation studies comparing portable monitor and polysomnogram testing have flawed study designs, are underpowered, and used monitors of older technology.
As a result of the growing acceptance of portable monitor testing, a wide spectrum of testing options is now available for the diagnosis of sleep apnea. The reduced number of sensors and technologist time required for portable monitor testing will increase patient access to this evaluation at reduced cost. However, the reduced complexity of portable monitor testing compared to polysomnography enables it to be used by non-sleep specialists who may not have the training and expertise to properly interpret the findings and adequately manage the patients.
Despite the limitations of portable monitor testing, critical factors are driving its greater and greater role in the management of patients with sleep apnea. First and most important, it’s now recognized that obstructive sleep apnea is a major public health issue. It’s more prevalent than diabetes and asthma. It’s a known risk factor for industrial and motor vehicle accidents. It’s a risk factor for cardiovascular events and death. The prevalence and clinical importance of sleep apnea make it impossible for the diagnosis and management of these patients to remain confined to a particular subspecialty. Like diabetes and asthma, care of patients with sleep apnea is likely to move eventually into primary care practice.
Cost of testing is driving insurance carriers in the United States to authorize portable monitor testing instead of polysomnography for their beneficiaries. Looking at the 2012 Centers for Medicare and Medicaid Services Reimbursement Fee for Metropolitan Philadelphia, in-laboratory polysomnography pays about $800; a home sleep test with a six-channel portable monitor pays $212; and a home sleep test with at least three channels, $99.
In the United States, the use of portable monitor testing has been largely dependent on whether the patient’s health care system is fee-for-service or capitated care. The University of Pennsylvania Health System represents a fee-for-service model. The Veterans Health Administration and Kaiser Permanente represent capitated care models. A provider facing a patient who has daytime sleepiness, witnessed apneas, and snoring will reach into their toolbox and select those tools that are available to take care of the patient. In the VA system, where we don’t have sufficient in-laboratory resources, many providers have been using portable monitor testing, whereas in fee-for-service health care, sleep centers have relied almost exclusively on in-laboratory testing.
Aggressive market forces in the United States are now challenging the use of polysomnography in fee-for-service systems in an effort to confront the growing cost of medical care. Sleep specialists in the private sector are being forced by insurance carriers to adopt portable monitor testing. Although we now have strong evidence supporting the use of portable monitors in the ambulatory management of patients with a high test probability of obstructive sleep apnea, this model has not been tested in community-based populations. The use of home sleep testing in a patient population with a high pretest probability of sleep apnea minimizes the number of negative studies. The application of these management pathways in community-based populations in which there will be lower risk of sleep apnea is likely to result in a greater number of negative studies in symptomatic patients, increasing the need for in-laboratory testing to rule out false negatives. An ambulatory management pathway that works in a high risk patient population may not be cost-effective in one with lower overall risk.
The title of this debate is “In-Laboratory Polysomnography Is on Life Support: The Future of Sleep Medicine Is Home Sleep Studies.” I don’t believe that polysomnography is on life support. You can’t run an ambulatory management program without having polysomnography serving as a safety net to catch those people who are not candidates for the home testing and patients who require more comprehensive testing. While I do believe the future is in home sleep studies, I’m not sure that future is going to be totally within sleep medicine. I think the diagnosis and management of most patients with obstructive sleep apnea will eventually move into primary care.
Regardless of what the future holds, a number of issues need to be urgently addressed. We need to rapidly adopt portable monitor testing with the new emerging technologies in telemedicine to demonstrate the ability to deliver care to patients with obstructive sleep apnea that results in clinical outcomes similar to those with in-laboratory management. We need to standardize the portable monitors and signals measured so that there is not such a disparate array; we need to perform high-quality patient-centered outcome research to assess the monitors in community-based populations and in patients with other cardiopulmonary diseases, different ethnic groups, and the elderly; and finally, we need to perform high-quality prospective studies to determine if ambulatory management of obstructive sleep apnea is indeed cost-effective.
Portable monitoring is here to stay. Instead of trying to put the horse back into the barn, we should figure out how to saddle it!
THE FLIP SIDE
Taking the con side of the debate, “In Laboratory Polysomnography Is on Life Support: The Future of Sleep Medicine Is Home Sleep Studies,” was Allan I. Pack, MBChB, PhD.
Allan I. Pack, MBChB, PhD: Is in-laboratory polysomnography on life support? I think that’s the wrong question. The implications of this switch to home studies have occurred very rapidly and have had major implications for the financial base of sleep medicine. Thus, the question is the following: is sleep medicine, not polysomnography, actually on life support due to the advent of home sleep studies that are poorly reimbursed?
There are a few key components of this debate. In the last 10 years, there has been dramatic growth in the number of sleep studies. The question is how much of this growth is increased recognition and how much overtesting? There is no definitive answer. We don’t have data. I would argue that we actually are not testing enough. There are still a lot of people out there waiting to be diagnosed. The recent studies of the high prevalence of unrecognized obstructive sleep apnea in obese type 2 diabetics support this assertion.1 But the perception that we overtest is out there and indeed was discussed on National Public Radio. So how can we counter the perception that we’re abusing the system? I would argue that one of the things we need is much stricter accreditation standards. The idea that a key principle of an accreditation system is minimal standards and do what the members (physicians) want is not sufficient. Accreditation should ensure that we do what is best for our patients, not ourselves. Accreditation needs criteria to assess overtesting; and you need to be willing to not accredit places that you think are overtesting. Accreditation needs to have teeth.
Another important message is that sleep apnea diagnostic testing should not be seen as a cost but as an investment. If we identify people with obstructive sleep apnea and get them effectively treated, we are going to reduce downstream costs. So we need to change the debate with payors.
There are data, including from Dr Kuna,2 that an entirely out-of-laboratory pathway can deliver identical outcomes of treatment to the traditional in-laboratory pathway. The out-of-lab pathway uses home sleep studies and auto-CPAP for CPAP titration. However, this study was done in patients with high pretest probabilities of sleep apnea and was conducted by professionals with extensive training in sleep medicine. Thus, it is not generalizable to other settings or other types of patients. A recent study from Spain3 showed that therapeutic decisions based on in-laboratory studies or home studies in the same patients were similar in patients with severe sleep apnea but not in those with more moderate disease.
We should start thinking about sleep apnea in terms of personalized medicine. There are different categories of patients out there. As a field, we’ve always taken a view that it’s one-size-fits-all; before it was the in-lab study and now it’s the home study. We really need to think about which patients are best served if you put them straight on auto-CPAP, by doing an in-lab study, or by going straight to a home study. I think that’s a more helpful way to think about it.
Dr Kuna talked about the cost of diagnosis; but it’s not just the cost of the diagnosis that is important if you’re doing an economic analysis. A paper4 in SLEEP last year actually came to the conclusion that the cheapest way of diagnosing and managing patients was in-lab studies. Let me explain the reason. The diagnostic cost of the in-lab study was clearly higher, but you had enhanced diagnostic accuracy. They calculated downstream costs of cardiovascular events, crashes, etc. If you missed patients using home studies, then you were accumulating costs because you weren’t treating them. The analysis showed that the total costs—if you added the diagnostic costs and the downstream costs—were actually less with in-lab PSG. But clearly these economic analyses are all based on assumptions. The key message from this study is don’t just look at what it costs you for each test. You have to figure in diagnostic accuracy and what reductions in costs are happening downstream.
Home studies have arrived and, in the United States, particularly in Massachusetts, they’re having a profound effect. Companies like Sleep Management Solutions have popped up, and plans like Tufts Health Plan have turned over management of all their sleep studies to this company. If you go to their Web site, Sleep Management Solutions says we’re here to serve the payors. They’re not focused on serving patients. They say, let us manage your sleep diagnostics and we will reduce your total diagnostic costs. They decide which test a patient gets—home study or an in-lab study—not the physician. As expected, most of the patients are steered to home sleep studies. And some of these companies, including Sleep Management Solutions, actually provide the home sleep study and the CPAP machine. There are no data on how well this strategy is working from the patients’ perspective.
This change took place rapidly in Massachusetts. The number of in-lab PSGs dropped by 50% to 60%. It had a profound impact on the ability of sleep medicine physicians and sleep centers in Massachusetts to survive. One day the Tufts plan would not reimburse for home sleep studies; the next day they were mandated with no discussion. Basically, an overnight change. If the Massachusetts model spreads across the country, it’s going to have unintended consequences and the change is going to be profound.
This has led to what I call “The Wild West of Sleep Apnea Testing,” because now a number of companies have sprung up that will allow you to order your test on the Web for yourself for $499. Primary care physicians can order sleep studies. Patients themselves can order sleep studies.
The one area in which I would disagree with Dr Kuna is whether primary care physicians can take on diagnosis and management of obstructive sleep apnea. When we talk to the primary care physicians in the Penn System, they indicate that they don’t have time for this. They are overwhelmed with so much to do, and they want us to help manage their patients. So I agree with Dr Kuna that it’s intellectually possible; there’s nothing terribly difficult about it, but is it doable in practice?
I think the real question is the following: What is the future of sleep medicine? Have we run this ship onto the rocks? How do we right the ship? The strategy we’ve been advocating, and I wrote a commentary in the Journal of Clinical Sleep Medicine,5 is focus on outcomes, as well as seek a new model of reimbursement. This is a field that has never been a diagnostic field. It is a chronic care management field. This is not an argument about in-lab versus in-home. This is an argument about how best to diagnose patients and get them effectively treated. The American Academy of Sleep Medicine has proposed an integrated sleep management delivery model to Medicare as part of the CMS Innovation Center Challenge that would be outcomes based. We’ve also been advocating changing the accreditation for sleep centers so that accreditation is based on outcomes.5 This was also a major recommendation of the Institute of Medicine report on sleep and its disorders in 2006.6 For me, the main question is not the method of diagnosis. I agree with Dr Kuna that home studies are going to be part of what we’re going to do; and we have to figure out which patients are best suited for this strategy. But sleep medicine was never a diagnostic discipline. We need to figure out how we deliver the best outcomes of care for the millions of Americans with sleep disorders in a cost-effective manner. That needs to be the focus of the future of the field of sleep medicine.
- Foster GD, Sanders MH, Millman R, et al; Sleep Ahead Research Group. Obstructive sleep apnea among obese patients with type 2 diabetes. Diabetes Care. 2009;32(6):1017-9. PMCID: PMC2681024.
- Kuna ST, Gurubhagavatula I, Maislin G, et al. Noninferiority of functional outcome in ambulatory management of obstructive sleep apnea. Am J Respir Crit Care Med. 2011;183(9):1238-44.
- Masa JF, Corral J, Pereira R, et al. Therapeutic decision-making for sleep apnea and hypopnea syndrome using home respiratory polygraphy: a large multicentric study. Am J Respir Crit Care Med. 2011;184(8):964-71.
- Pietzsch JB, Garner A, Cipriano LE, Linehan JH. An integrated health-economic analysis of diagnostic and therapeutic strategies in the treatment of moderate-to-severe obstructive sleep apnea. Sleep. 2011;34(6):695-709. PMCID: 3098944.
- Pack AI. Sleep medicine: strategies for change. J Clin Sleep Med. 2011;7(6):577-9. PMCID: 3227700.
- Colten HR, Altevogt BM. Sleep Disorders and Sleep Deprivation: An Unmet Public Health Problem. Washington, DC: The National Academies Press; 2006.