E.R. McFadden, Jr, MD
Introduction
Obstructive sleep apnea (OSA) is a common clinical problem that affects between 2% and 25% of the population. This condition is associated with significant morbidity that takes the form of daytime sleepiness and cardiovascular dysfunction and hypertension. There is also a significant disruption in the quality of life, and there are frequently associated events such as motor vehicle and other accidents.[1]
A 2-year ATS workshop examined current approaches to OSA, critically reviewing the existing data on the 3 major treatment modalities available. Workshop participants looked at patients most likely to benefit from a particular modality, economic issues related to treatment options, and related clinical issues. The workshop findings were presented during the ATS meeting.
Current Treatments
Current OSA treatments consist of:
Pressure devices: continuous positive pressure (CPAP); bilevel pressure (BIPAP); and auto-titrating continuous positive pressure (ATAP)
Oral appliances (mandibular-repositioning devices and tongue-restraining devices)
Upper airway reconstruction involving soft-tissue (palatal procedures and genioglossus advancement) and bony structures (maxillary-mandibular advancement and hyoid resuspension)
The treatment recommended often depends upon how the patient enters the healthcare system. A pulmonary/sleep physician would most likely recommended pressure-assisted ventilation, a dentist might favor an oral appliance, and an otolaryngologist or an oral/facial maxillary surgeon might well favor reconstruction.
Specifically, workshop participants wanted to determine the short- and long-term benefits (greater than 2 months), side effects, adherence rates, and adverse reactions associated with each treatment approach. They also wished to review the cost and benefits, identify subgroups likely to respond to each modality, determine the gaps in current information, and finally formulate a stepwise therapeutic approach.
Effectiveness was judged from both acute and long-term viewpoints, using indices such as the apnea hypopnea index (AHI), changes in nocturnal oxygen saturation, sleep architecture, blood pressure, and upper airway size. In addition to the above, the long-term effects sought were improvements in the quality of life, changes in daytime sleepiness, and healthcare utilization.
Show Me the Money
Economic issues, though not the primary focus of clinical decision making, clearly have an increasingly important role in selecting therapies. This is particularly true in any attempt to analyze the cost-effectiveness of a specific treatment.
As P. Peele, PhD, of Pittsburgh, Pennsylvania, noted, evaluating cost-effectiveness is a complex issue involving multiple parameters, such as the differentiation of cost from price.[2] The first is related to the utilization of resources and the second is the charge arbitrarily applied to that service. For a valid assessment, costs must be considered across populations, therapies, and methods of application. They must also be viewed from the perspective of the person paying for them, ie, society in general, care providers, the insurer, and the patient.
The assumption underlying cost-effectiveness ratios assumes a linear effect, ie, the greater the cost, the greater the benefit. But this might not necessarily be so. Some of the therapies employed for sleep apnea produce immediate effects at great cost with minor long-term financial consequences.
Positive Pressure Therapy
C.W. Atwood, Jr., MD, also from Pittsburgh, discussed the costs and benefits of positive pressure therapies (CPAP, BIPAP, and ATAP).[3] CPAP has been studied most extensively, and there are good data showing meaningful acute effects on apnea and hypopnea, oxygen desaturation, nocturnal hemodynamics, sympathetic nervous tone, sleep architecture, and decreases in negative pleural pressures during expiration. There are fewer data on the long-term effects, but here, too, the evidence supports continuous improvement in many of these same variables.
There is also enhancement in cognition, quality of life, and the sense of overall well-being associated with the use of these therapies, Dr. Atwood reported. The benefits are rapid, occurring within 1-2 nights. Patient acceptance approaches 90% and in some studies adherence is approximately 68% for 5 years of follow-up, although some recent randomized controlled trials found adherence to be approximately 40%.[4,5] The most troublesome side effects are nasal irritation, stuffiness, eye irritation, and skin abrasion, but there are no data on whether the side effects interfere with use or effectiveness. CPAP works best in the moderate-to-severe category of OSA and the available information, although somewhat limited, indicates that the cost-benefit ratio appears favorable.
Oral Appliance Therapy
Whereas studies of positive-pressure therapies have been fairly extensive, there are far fewer data on the effectiveness of oral appliance therapy, noted K.A. Ferguson, MD, from London, Ontario, Canada.[6] What's more, studies that are available frequently lack acceptable controls.
There are no controlled clinical trials, for example, comparing the different devices and there is limited information as to whether positioning the jaw or tongue actually influences airway size. Many studies lack a complete description of the protocol and/or the appliance, do not use uniform definitions of success, or follow the patients in a disciplined fashion for acceptable times.
Study results vary widely with regard to acute and chronic success rates. On the whole, there appears to be less effect on nocturnal oxygenation than with CPAP. Side effects have been poorly monitored, as have adherence rates. Complications vary from salivation to temporal mandibular dysfunction. It was the opinion of workshop participants that these devices are not first-line therapy for severe OSA but may be helpful in individuals who fail CPAP.
Surgical Therapy
Surgical approaches to OSA treatment include upper airway reconstruction involving soft tissue and bony structures. Evaluation via a cost-benefit ratio of such approaches is difficult, however, because of a lack of clinical trial data. B.T. Woodson, MD, of Milwaukee, Wisconsin, noted that there are a large number of case studies in the literature but a dearth of randomized, controlled clinical trials that review the various forms of surgery or compare these modalities with other available treatments.[7] In addition, he said, there are minimal outcome data for the surgical management of OSA.
From the data available, it would appear that subjects likely to benefit from surgical intervention are those with facial defects, retrognathia, and/or large tonsils. A selected group of patients with severe OSA who are either not adherent to or unable to tolerate CPAP may benefit from tracheostomy. The presence of morbid obesity frequently interferes with the success of the surgical approaches, Dr. Woodson noted.
Summary
The workshop's summary statement points out that overall the approaches to the treatment in OSA are fragmented and that the current data do not allow for detailed cost-effective analysis or evidence-based guidelines. Randomized controlled trials comparing the 3 possible interventions are not available.
The best evidence for a successful outcome appears to favor assisted positive-pressure ventilation, with CPAP recommended as the initial treatment for chronic to severe OSA. Surgical procedures on the palate add greatly to the cost of therapy and may possibly compromise the effectiveness of CPAP. Oral appliances suffer from minimal outcomes data, and long-term adherence is uncertain. Surgical approaches are the most costly of available treatments for OSA and, to date, are of proven benefit in individuals with documented upper airway obstruction or mandibular deformities. Their use in patients with moderate to severe sleep apnea who do not respond to other forms of treatment may be beneficial.
