Download Sleep Medicine—Time for a Change

SPECIAL ARTICLES
Sleep Medicine—Time for a Change
Peretz Lavie, Ph.D.
Lloyd Rigler Sleep Apnea Research Laboratory, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
Abstract: The growing awareness of obstructive sleep apnea and its
profound impact on patients’ quality of life and health has resulted in
an unprecedented growth in sleep medicine in the last 2 decades. The
present paper argues that, based on recently accumulated knowledge
about the pathophysiology of cardiovascular morbidity in sleep apnea,
the practice of sleep medicine must be changed in order to improve patients’ care. The diagnosis of sleep apnea should be performed when
patients are aged 25 to 30 years, far younger than the approximately 50
years of age, which is when most patients usually receive a diagnosis
now, and programs of regular follow-up visits to assess patients’ con-
dition and compliance with treatment should be incorporated into the
everyday practice of sleep specialists. Because of the wide gap between
the number of sleep specialists and sleep clinics and the prevalence of
sleep apnea in the general population, an alliance between sleep medicine and family practitioners is necessary to ensure such changes. A
proposal for such an alliance is presented.
Keywords: Sleep medicine, sleep apnea, diagnosis, family medicine,
treatment
Citation: Lavie P. Sleep medicine—Time for a change. J Cin Sleep Med
2006;2(2):207-211.
Sleep Medicine—Unprecedented Growth Since the 1980s
are pulmonologists.1 This is a complete turnabout from the 1970s
and 1980s when the vast majority of sleep specialists were neurologists, psychiatrists, and psychologists. This may be changed,
however, as a result of the decision of the Accreditation Council
for Graduate Medical Education to approve the sleep medicine
fellowship training programs that may open sleep medicine to
other medical specialties.
Sleep medicine has seen an unprecedented growth in the last
2 decades. It is estimated that, throughout the United States in
1292 sleep clinics, at least 1.17 million people were examined
during 2001.1 These numbers have likely doubled since then, and
other countries have seen a similar growth in the field of sleep
medicine.2 This dramatic increase in sleep clinics and the number of polysomnographic recordings is undoubtedly explained
by the growing awareness of obstructive sleep apnea syndrome
and its profound impact on patients’ quality of life and health.
At least 85% of patients are referred to a sleep examination in a
laboratory because of suspected sleep apnea, which affects, in at
least moderate form, 1 in 10 men and 1 in 25 women.3 For people
over 60 years of age and in certain high-risk populations, such
as obese people or habitual snorers, there are more people with
breathing disorders during sleep than without.4 The fact that the
field of sleep medicine is overwhelmingly centered on a single
disorder, sleep apnea, explains why sleep medicine has become
almost a subspecialty of pulmonary medicine in the last few years
and why more than 50% of diagnostic sleep laboratory directors
Sleep Medicine—Practiced Now as 20 Years Ago
The focus of sleep medicine on a single disorder and the dominance of pulmonologists in this field have not affected the practice of sleep medicine in any major way. Examinations to diagnose breathing disorders in sleep are carried out in more or less
the same way as they were done 20 or 30 years ago by sleep specialists who mostly examined patients complaining of insomnia
or suspected sufferers of narcolepsy.5 There has been, however,
impressive progress in data-acquisition and data-storage technologies. Electrophysiologic recordings have moved from analog
to digital, and data are no longer stored on miles and miles of recording paper but on compact, miniature, digital, storage media.
Also, more detailed and focused guidelines have been developed
to quantify respiratory events during sleep that were not given
much clinical importance just 20 years ago.
Thus, a person suspected of having sleep apnea is referred to a
sleep clinic and spends the night there connected to electrophysiologic recordings that monitor electroencephalography, electrooculography, electromyography, respiratory effort, airflow, body
position, and arterial oxygen saturation level, all of which provide
the necessary information for a diagnosis. Presenting symptoms
and medical history are also taken into consideration in the diagnostic process and treatment recommendation. To save the patients’ time and the insurance companies’ money, many of the diagnostic sleep recordings performed nowadays are based on only
half of the night (the so-called split-night procedure).6 If the pa-
Disclosure Statement
This was not an industry supported study. Dr. Lavie is a consultant and board
member of Itamar Medical Ltd. and SLP Ltd; is a board member of Sleep
Medicine Center, Israel, and Sleep Health Centers, U.S.; has received research support from Itamar Medical Ltd. and SLP Ltd.; and has participated
in speaking engagements supported by Itamar Medical and Medcare.
Submitted for publication September 21, 2005
Accepted for publication November 25, 2005
Address correspondence to: Peretz Lavie, Ph.D., Lloyd Rigler Sleep Apnea
Research Laboratory, Rappaport Building, Efron St. Bat-Galim, Haifa 31096,
Israel; Tel: 972 4 8120881; Fax: 972 4 8343934; E-mail: [email protected].
ac.il
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P Lavie
specific “redox sensitive” transcription factors that encode proinflammatory cytokines.21,22 This results in activation of endothelial cells, leukocytes, and platelets and in increased production
of adhesion molecules that lead to endothelial cell-leukocyte
interaction and adhesion and increased toxicity of lymphocytes
against endothelial cells, processes resulting in endothelial dysfunction.23-26 Indeed, a state of endothelial dysfunction, considered prognostic of future cardiovascular morbidity,27 has been
demonstrated in patients with sleep apnea who are free from any
overt cardiovascular diseases in several studies.28-33 Findings that
relatively young patients with sleep apnea, free of any overt cardiovascular disease, display early signs of atherosclerosis, such
as increased carotid artery wall thickness, increased arterial stiffness, and atheromas, as well as findings that sleep-apnea severity
significantly and independently correlate with these early atherosclerotic markers, further support this concept.34,35
Atherogenic processes start early in life, most likely during the
first or second decades, and progress over decades and are affected by obesity, hyperlipidemia, hypertension, and diabetes that
also affect the transformation of atherogenic processes to overt
cardiovascular morbidity.36 Recent research, however, has shown
that oxidative stress, inflammation, and endothelial dysfunction
also play a role in atherosclerosis. Immune mechanisms interact
with metabolic risk factors to initiate, propagate, and activate lesions in the arterial tree.37 Many of the factors demonstrated in
sleep apnea, such as oxidative stress, inflammation, increased
production of adhesion molecules, and increased adhesion between endothelial cells and leucocytes, have also been implicated
in atherosclerosis. Thus, it can be safely assumed that breathing
disorders in sleep accelerate atherogenic processes. This process
most probably starts to accrue during the very first nights that
hypoxemic events appear, regardless of the patient’s symptoms,
and from that time on, night after night, the patient’s blood vessels and heart are exposed to the aggression of oxygen reactive
species that are formed with the ebb and flow of arterial oxygen
level. Patients, however, are generally referred to a sleep clinic
for diagnosis only when the characteristic symptoms of snoring
or excessive daytime sleepiness start bothering them or their bed
partners, generally around the age of 50. Although there are no
well-controlled studies on the natural evolution of sleep apnea,
there is evidence that apneas are already prevalent in the third decade of life. Based on the Wisconsin study, 17% of men aged 30
to 39 have a form of sleep apnea classified as mild or beyond, and
6.2% have sleep apneas classified as moderate or beyond.3 Furthermore, it can be safely assumed that the rates in this younger
age group are much higher in specific high-risk populations such
as the obese and habitual snorers. Thus, a diagnosis of sleep apnea at the age of 50 may be delayed by 10 to 20 years from the
time patients first display breathing disorders in sleep. This delay
may be crucial because, during that time, there is an accumulated
damage to the cardiovascular system. To prevent this damage, the
diagnosis and treatment of breathing disorders in sleep should be
done at the earliest age possible. Thus, there is an urgent need to
lower the age of diagnosis from age 50 to between 25 and 30.
This conclusion is further supported by the results of mortality studies of patients with breathing disorders in sleep. Without
exception, all studies have demonstrated an age-decline trend in
mortality in comparison with the general population, with the
highest risk of mortality in patients younger than 50.38-43 Furthermore, in a recently published paper Yaggi et al44 reported that
tient is judged by the attending technician to suffer from breathing
disorders in sleep that are above a threshold severity, the second
half of the night is used to determine the appropriate air pressure
for nasal continuous positive airway pressure (CPAP) treatment.
This is the treatment of choice for the vast majority of patients
with moderate to severe forms of breathing disorders in sleep.
Unfortunately, in many cases, the only encounter the patient
has with the sleep laboratory is a single night for diagnostic or diagnostic-plus-titration purposes, as the prescribed CPAP treatment
is administered elsewhere; seldom is there a posttreatment sleep
evaluation or other regular follow-up, a situation that is worst in
minority-serving institutions.7 In this paper, I argue that the time
is ripe for a major change in the way sleep medicine is practiced
and that this change is crucial to improve the quality of care for
patients suffering from breathing disorders in sleep and to prevent cardiovascular morbidity. My position stems from the newly
acquired understanding of the pathophysiology of cardiovascular
morbidity in patients with sleep apnea syndrome and from the
resultant need to improve quality of care for these patients.
Significance of Early Diagnosis
The association of breathing disorders in sleep with cardiovascular morbidity has been a major impetus in the medical community for increased awareness about the significance of breathing
disorders in sleep. At the time of a sleep apnea diagnosis, it is
commonly found that more than half of the people diagnosed with
the disorder also suffer from hypertension.8 In a patient population numbering 118,000 who were diagnosed with sleep apnea
through the United States Department of Veteran Affairs health
administration system, 60.1% suffered from hypertension, 32.9%
diabetes mellitus, 27.6% cardiovascular disease including myocardial infraction and angina, 13.5% heart failure, and 5.7% had
endured a cerebrovascular accident.9 Conversely, among patients
with cardiovascular diseases, breathing disorders in sleep are a
prevalent finding.10 These cross-sectional data on the association between cardiovascular morbidity and breathing disorders in
sleep are supported by large population-based studies demonstrating that this association is independent of all possible confounding cardiovascular risk factors11-14 and, at least for hypertension,
follows a dose-related relationship.14 A canine model of sleep apnea,15 as well as intervention16 and prospective studies,17 provide
further support that breathing disorders in sleep are causally related to hypertension.
The association between breathing disorders in sleep and cardiovascular morbidity has been attributed to increased sympathetic activation; to swings in intrathoracic pressure; and, in recent
years, to acceleration of atherogenic processes that are uniquely
triggered by the apnea-related intermittent hypoxia and resultant
oxidative stress.18 This latter explanation provides a better understanding of the natural evolution of cardiovascular morbidities in
patients with breathing disorders in sleep and has major implications regarding the diagnosis and treatment of sleep apnea.
In light of the recent observations on oxidative stress in sleep
apnea, the following chain of events has been proposed.18 Breathing disorders in sleep are associated with repeated occurrence of
hypoxia/reoxygenation events that, similar to the effect of restoration of blood circulation to ischemic tissue, result in increased
production of oxygen reactive species.19,20 Once produced, oxidant molecules inflict injury on surrounding tissues and activate
Journal of Clinical Sleep Medicine, Vol. 2, No. 2, 2006
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Sleep Medicine – Time for a Change
sleep apnea was associated with increased mortality irrespective
of treatment administered. Thus, delaying diagnosis and treatment
to the age of 50 may be too late for many of the patients who are
at maximal risk of dying and who have already developed cardiovascular morbidity.
comprehensive sleep centers.
To put this alliance into action, in each family practitioner’s
clinic, a team of representative clinicians and nurses will be
trained in the essentials of sleep medicine, particularly in sleep
apnea and in its treatment. The team will be trained to identify
people with a high likelihood of having sleep-disordered breathing, in performing ambulatory home monitoring tests to diagnose
sleep apnea, and in reaching a decision regarding treatment for
some of the patients. I am well aware that a joint task force of the
American Thoracic Society, the American College of Chest Physicians, and the American Academy of Sleep Medicine did not
recommend the use of ambulatory monitoring for the diagnosis
of sleep apnea.49,50 However, in a recent editorial entitled “Pulmonary physicians in the practice of sleep medicine,” the presidents
of the 3 societies declared that “discussion is underway to develop practical guidelines for the utilization of portable monitoring for specific indications.”51 Thus, given the rapid progress in
the development of ambulatory diagnostic technologies, the increased economic burden of sleep-apnea diagnosis, and the need
to change the practice of sleep medicine, a formal endorsement of
ambulatory monitoring by the professional societies, particularly
in patients with high likelihood of having disease,52 may be forthcoming. Cases involving other sleep disorders, or associated with
complex comorbidities or when diagnosis is in doubt, will be referred to the supervising sleep clinic. To ensure continuity of care,
a program of supervising nasal CPAP treatment, including regular
follow-up visits and follow-up sleep studies, will be developed in
each primary-care or family-medicine practice in collaboration
with the supervising sleep clinic.
Although such an alliance is also possible with other generalists like internists or with specialists like otolaryngologists, the
advantage of primary-care or family-medicine physicians in this
context is that knowing their patients on a more personal level,
they are better positioned to achieve the goals of such a program.
Being more familiar with the patients, family practitioners will be
able to identify younger people who have a high risk for sleep apnea and examine them. Using patient-friendly ambulatory monitoring devices, diagnosis will be simplified and the economic burden of diagnostic sleep recordings will be considerably reduced.
The role of generalists and subspecialties in providing healthcare
has been long debated. A large number of studies have examined how physician specialty affects measure of care and clinical
outcomes in diseases such as hypertension, non–insulin-dependent diabetes, asthma, rheumatoid arthritis, and coronary artery
disease and chronic heart failure (see a review in reference 53).
However, in a manner different from the practice in which patients
are treated by either a generalists or by a specialist, the proposed
model for sleep medicine is of a joint collaborative program with
close communication between the generalist and specialist. Thus,
an efficient communication between the primary-care or familymedicine physicians and sleep specialists, which is generally considered to be suboptimal in the “either-or” model,54 is essential
for the success of such a program. This can be based on sharing
data and medical information via the Internet, conducting periodic joint clinical meetings, and providing real-time telephone or
Internet consultations whenever the need arise.
To ensure the widespread success of such an alliance, family-medicine or primary-care practitioners should be educated
in sleep medicine. Because the time dedicated to sleep medicine
in the curricula of medical schools is a meager few hours in 4
Improving Treatment
A second aspect of sleep medicine that needs a change is treatment administration and management for patients with breathing
disorders in sleep. Even though treatment with nasal CPAP has
been proven time and again to effectively control the apneas and
to reduce morbidity,45,46 compliance with treatment is poor and
varies from 46% to 80%.47,48 One of the possible reasons for the
poor compliance is the lack of continuity of care in sleep medicine. While diagnosis of sleep apnea is done in the sleep clinic
by a sleep specialist, nasal CPAP treatment is administered outside the sleep laboratory by people who are not sleep specialists. The lack of continuity of care manifests itself not only in
the people who administer treatment, but also in the follow-up of
treated patients. Few of the patients who are administered nasal
CPAP devices receive regular follow-up in order to verify efficacy of treatment or to determine if there is a need to consider
different treatment modalities. Follow-up of a patient’s condition,
regardless of the level of treatment, almost goes without saying
in medicine. Patients who have been diagnosed with diabetes, hypertension, or depression are not left to fend themselves after their
condition has been diagnosed and treatment prescribed for it. The
sleep specialist’s role should not end with signing the diagnosis
and recommending treatment; this must be followed by regular
meetings with the patients to allow assessment of the patient’s
condition and to evaluate changes in the severity of the syndrome
and in the degree of risk to the patient. The practice of sleep medicine must be changed to ensure an improvement in patients’ care.
A New Model for Sleep Medicine
What changes should be instituted to facilitate the diagnosis
and treatment of sleep apnea in patients in their 20s and 30s as
opposed to common practice today, when diagnosis and treatment
usually begin when the patient is 50 year of age? How can compliance with treatment and quality of care be improved? Given the
prevalence of breathing disorders in sleep, particularly in specific
high-risk populations, it will be very difficult to achieve these
goals by relying on sleep specialists alone, whose role in many
cases is completed once the diagnosis letter is signed. Earlier diagnosis and treatment, along with improved compliance and quality of care, call for a structured and well-planned alliance between
sleep medicine and family medicine or primary-care medicine. In
the proposed model, sleep clinics will become allied with several
clinics of primary-care or family-medicine practitioners within a
defined geographic area that will take on some of the sleep clinic
responsibilities, particularly those of early diagnosis of sleep apnea, supervising nasal CPAP treatment, and conducting regular
patients follow-up. This is similar to the guidelines of the American Academy of Sleep Medicine that recognizes 2 levels of sleep
facilities: the comprehensive sleep center and the sleep-related
breathing laboratory, a facility that focuses on breathing disorders
in sleep. Thus, I suggest expanding the concept of a secondary
sleep-related breathing laboratory to selected clinics of family
practitioners that will be allied with and supported by supervising
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P Lavie
years,55,56 such an education must be completed at the postgraduate level. This should not be a long process; experience has shown
that the learning curve for primary care physicians is relatively
short. There is evidence that educational intervention is effective
in increasing rates of recognition and diagnosis of sleep-disordered breathing by primary care practitioners57 and that patients’
compliance rates with CPAP treatment, when managed by their
primary care physicians, is not different from the compliance rates
of patients whose case is managed by sleep specialists.58 Here, the
Accreditation Council for Graduate Medical Education decision
to approve the sleep medicine fellowship training programs will
be of great help.
Is such collaboration between sleep medicine and family practitioners feasible? First, based on a cross-sectional survey of 40
primary care clinics and offices in the United States, Germany,
and Spain, Netzer et al59 reported that one third of the 8000 people
seen in these clinics had a high pretest probability of having sleep
apnea, clearly suggesting that primary care practitioners encounter a high demand for services to diagnose and manage breathing
disorders in sleep in their daily practice. Second, there is already
a successful test case for such collaboration. In the so called Walla-Walla project, family practitioners trained by sleep specialists
increased their referral for sleep testing 8-fold over a period of 2
years. This resulted in a diagnosis of sleep-related breathing disorders in 81% of the referred patients.57
In conclusion, sleep medicine has seen a phenomenal growth in
recent years, but the practice of sleep medicine must be changed
in order to achieve better patient care and implement more-effective treatments to prevent cardiovascular morbidity in patients
with sleep apnea. A well-planned alliance with family medicine
will achieve these goals with minimum investment and maximum
efficacy.
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