The report is a product of the VA/HSR Evidence Synthesis Program.

Obstructive Sleep Apnea: A Systematic Review

Obstructive sleep apnea (OSA) is a chronic condition that results from repeated closure of the upper airway during sleep that results in reduced airflow (hypopnea) or complete airflow cessation (apnea), which leads to cyclic sleep disruption. Patients with OSA frequently experience excessive daytime sleepiness and decreased quality of life. OSA also has been associated with a higher risk of myocardial infarction, heart failure, stroke, and cognitive decline. The estimated prevalence of mild to severe OSA in the United States (2007-2010 data) among 30- to 70-year-olds is 34% for men and 17% for women. Obesity is one of the major risk factors for OSA, and in 2010, among 1.8 million U.S. Veterans receiving outpatient care at 136 VA facilities, 37% had a body mass index (BMI) ≥ 30 kg/m2. These data suggest that a substantial number of Veterans are at increased risk for OSA. Moreover, VA and other healthcare systems often struggle to provide timely OSA diagnostic and treatment services, partially due to a rising demand for services, but also due to a declining pipeline of new sleep specialist physicians. To address this problem, some healthcare systems have sought to reduce reliance on sleep specialist physicians in the evaluation and treatment of patients with suspected or diagnosed OSA, through the use of non-sleep specialist practitioners, electronic consultation, and auto-titrating treatment devices.

This systematic review sought to assess the comparative effectiveness, harms, and costs of care models for OSA evaluation and treatment. Investigators with VA's Evidence-based Synthesis Program Center located in Minneapolis, Minnesota searched MEDLINE and CINAHL between January 2000 and May 2016. From this search, they identified eight reports (4 randomized controlled trials (RCTs) and 4 observational studies) that evaluated case-finding and care provided by non-sleep specialist practitioners versus sleep specialist physicians (SSP). Twenty-seven reports (25 RCTs and 2 observational studies) assessed in-home auto-titrating continuous positive airway pressure (APAP) technology versus standard continuous positive airway pressure (CPAP) titrated by in-lab polysomnogram (PSG) as options for PAP titration or treatment. Investigators used these data to address the following key questions for adults with suspected or diagnosed OSA:

• What are the effectiveness/harms/resource utilization of case finding and care provided by practitioners who are not sleep physicians (i.e., primary care providers, physician assistants, nurses, and respiratory therapists) compared to sleep specialist physicians?
• What are the effectiveness/harms/resource utilization of electronic consultation versus interactive (i.e., in-person, telephone) consultation?
• What are the effectiveness/harms/resource utilization of using in-home APAP technology compared to standard CPAP titrated by in-lab PSG?

Summary of Review
Among patients with suspected or diagnosed OSA, primary care providers and sleep-specialist nurses provided similar outcomes to SSPs, although most clinical outcomes were infrequently and inconsistently reported. Further, non-SSPs were often highly experienced in sleep medicine. At-home APAP provided similar outcomes to CPAP titrated in the PSG laboratory. Overall, evidence was insufficient regarding harm and access to care, and strength of evidence was low-to-moderate for other outcomes. No studies addressed electronic consultation for the management of known or suspected OSA. Specific findings showed:

Case Finding

• No studies assessed the diagnostic accuracy of non-sleep-specialist nurses for case finding and referral.
• One retrospective study reported good agreement between a primary care pulmonologist and a SSP on what sleep test to order for patients referred by their family physician.

Care

• Clinical (i.e., patient-centered) outcomes were infrequently and inconsistently reported. When reported, there was no significant difference in clinical outcomes between OSA treated by primary care/nurses and SSPs (moderate strength of evidence).
• Intermediate outcomes were more commonly reported. Sleep symptom scores were similar between groups (moderate strength of evidence).
• There was little evidence that treatment compliance differed between patients treated by SSPs and non-SSPs.
• Strength of evidence for access to care and adverse events was insufficient.

Titration

• Few studies compared clinical (i.e., patient-centered) outcomes between in-lab CPAP titration and at-home APAP titration.
• In limited reporting, CPAP and APAP provided generally similar measures of quality of life (moderate strength of evidence) and cognitive symptoms.
• Intermediate outcomes (i.e., sleep measures, blood pressure, adverse events, and compliance/adherence) were more commonly reported and generally similar. Strength of evidence for Epworth Sleepiness Scores (ESS) was moderate and strength of evidence for compliance was low. Strength of evidence for adverse events was insufficient.

Treatment

• Twenty-three studies compared CPAP treatment to APAP treatment. The studies enrolled patients with a broad range of baseline AHI values.
• Few studies reported clinical (i.e., patient-centered) outcomes other than quality of life and patient preference for one treatment approach over another. Quality of life, assessed with the SF-36, was generally similar between CPAP and APAP (moderate strength of evidence). Patient preference was generally similar or favored APAP in studies reporting statistical significance. Strength of evidence was insufficient for access to care.
• Intermediate outcomes, including post-treatment ESS scores, were frequently reported and generally similar for CPAP and APAP (moderate strength of evidence). Adverse events were mild and similar for CPAP and APAP (low strength of evidence).
• Compliance was similar for the CPAP and APAP treatment groups (moderate strength of evidence).

Future Research
Comparative effectiveness trials were lacking for all key questions and should be a high priority in the future. In addition, studies are needed to determine: 1) which patients derive the most benefit from treatment and should, therefore, be prioritized for testing and treatment; 2) whether newer models of care with less reliance on SSP time (either through utilization of other types of providers or electronic consultation) result in similar outcomes to traditional models; and 3) if effective, how such new models should be implemented. A large gap in evidence exists regarding the effectiveness of treatment for individuals without excessive daytime sleepiness – and on outcomes other than daytime sleepiness.

These future studies will be critical to effectively managing the dramatic increase in the numbers of patients being referred for evaluation and treatment of OSA.

Reference
Kunisaki KM, Khalil W, Koffel E, Pfannes L, Koeller E, MacDonald R, Greer N, Wilt TJ. The Comparative Effectiveness, Harms, and Cost of Care Models for the Evaluation and Treatment of Obstructive Sleep Apnea (OSA): A Systematic Review. VA ESP Project #09-009; 2016.

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