Sleep Apnea: A "Sleeping" Giant Awakens
ABSTRACT & COMMENTARY
Synopsis: By enhancing local expertise and training of primary care physicians in the recognition of sleep disorders, referrals for sleep studies increased by eight-fold, resulting in diagnosis of sleep-related breathing disorders in 81% and periodic leg movement disorders in 18% of cases over a two-year period.
Source: Ball EM, et al. Arch Intern Med 1997;157:419-424.
One of the most rapidly expanding areas of medicine is that of sleep disorders. Long shrouded in mystery, both the pathophysiology and management of sleep problems are increasingly scientifically grounded. Though sleep disturbances are estimated to affect more than 4% of the adult populations (exceeding the prevalence of diabetes), up until now, there has been limited formal training and expertise within the non-specialist community. Ball et al now report on a project undertaken to remedy this problem in a rural area of Washington state. Using the expertise of two internists with a special interest in sleep, a training program was undertaken including both live and optional videotaped sessions for the other internists in the community. Polysomnography (PSG) was usually interpreted by the "expert" physicians but sometimes by the ordering physicians. Polysomnograms include standard EEG, EMG, EKG, and respiratory monitoring. Most were performed in the patients’ homes.
During the two years of the project, 580 PSGs were performed. The frequency of sleep studies increased from 0.3% to 2% of all internal medicine patients. Consultation with the expert sleep physicians was obtained in 34% of cases. Of the 360 PSGs performed, 81% detected either obstructive sleep apnea syndrome (OSA) or upper airway resistance syndrome. (See Table.) The typical profile of a sleep apnea patient was a middle-aged obese male, but one-quarter of patients were female. Periodic leg movements of sleep was the next most prevalent diagnosis (18%). Compared to data from specialized sleep referral centers, the patients involved in this project were more likely to be female, and the respiratory disturbance index was lower. Compliance with CPAP was similar to reports from most sleep centers, and only 22% returned their machines.
Final Diagnosis of Patients Referred for PSGs
Final Diagnosis No. (%)
Sleep Hygiene 8.3
Circadian rhythm 4.7
Idiopathic CNS hypersomnia 0.3
COMMENT BY ALAN M. FEIN, MD
The impact of sleep disordered breathing on the public health is significant. Despite the nearly 40,000 cardiovascular deaths and the high incidence of disability and motor vehicle accidents attributed to sleep disorders, it is estimated that most patients remain undiagnosed. The level of physician recognition of these syndromes, at the primary care level, is clearly poor. Most sleep specialists are part of specialized centers, usually in urban areas. In this setting, pulmonary physicians, neurologists and psychiatrists are usually the specialists responsible for the conduct and interpretation of sleep studies. The availability of effective ventilatory therapy (CPAP or BIPAP) for OSA makes diagnosis a high priority. Thus, the report of Ball et al is an interesting approach to the problem of a highly prevalent but poorly recognized disorder. In this rural community, primary care internists provided a core sleep program, based in a primary care clinic. Using a relatively simple and concise training program available to all primary care physicians in the community, the frequency of recognition of sleep disorders increased, as evidenced by the eight-fold increase in the ordering of sleep studies. Diagnoses established included predominantly obstructive sleep apnea and periodic leg movements. Those with OSA were treated with CPAP with a crude measure of compliance at 80%.
This study is both encouraging and disturbing. Clearly, sleep apnea is a common but underrecognized illness. Primary care physicians can provide basic screening for this disorder. The primary care specialists responsible for the sleep program increased the referral for sleep testing, and PSGs were interpreted in many cases by the ordering primary care physician. OSA carries a significant risk to the patient’s long-term health. Based on what was reported, we know that the program improved the recognition of sleep disorders in this rural community. Whether this represents an interim measure or a long-term ideal is not clear from the information available. This program, however, does suggest at least a stopgap model for communities without immediate access to trained sleep specialists.