American Thoracic Society Statement on OSA Research

Dr. Susheel Patil is senior author on ATS report aimed to improve nuance in study design and reporting

Innovations in Pulmonology, Critical Care & Sleep Medicine | Fall 2023

Continuous positive airway pressure (CPAP) has long been the gold standard for treating obstructive sleep apnea (OSA) and improving symptoms of reduced sleep quality and daytime sleepiness. However, a recent report issued by the Agency for Healthcare Research and Quality (AHRQ), in response to a request from the Centers for Medicare Services, reviewed effectiveness data from 47 randomized clinical trials and questioned the long-term benefits of CPAP.

Susheel Patil, MD, PhD

“The AHRQ report focused specifically on certain outcomes, such as cardiovascular benefits, metabolic outcomes, motor vehicle accidents and long-term resolution of blood pressure control,” says Susheel Patil, MD, PhD, System Director, Sleep Medicine, University Hospitals Cleveland Medical Center. “However, the sleep medicine community was concerned about how the AHRQ approached this study. For example, they did not adequately discuss the benefits of CPAP in reducing sleepiness or improving patients’ sleep-related quality of life, which we know are clear advantages of CPAP. Furthermore, many trials excluded patients with active OSA-related symptoms, raising concerns that the AHRQ report lacked nuance and that stakeholders might misinterpret results.”

The AHRQ report concluded that long-term treatment of OSA with CPAP did not result in improved cardiovascular outcomes, based on a systematic review of randomized controlled trials and some non-randomized observational studies. The report did not highlight some of the potential ethical concerns in conducting randomized control trials that enroll symptomatic people for a long period of time.

The AHRQ report also did not provide specific guidance on how to overcome these challenges. So the American Thoracic Society (ATS) convened a workshop to evaluate how OSA research is conducted, especially in light of the ethics involved in assigning participants with active symptoms to a placebo group for a period of years.

“The objectives of the ATS workshop were to address three main areas,” says Dr. Patil, senior author on the workshop report. “How can we design better clinical trials? Are there alternative ways to study OSA treatments if we’re not able to conduct a clinical trial? And, lastly, how do we recruit patients for research studies?”

Workshop Outcomes

Lack of high-quality evidence. “We know that CPAP improves long-term outcomes in patients with OSA; however, we need to address our outstanding knowledge gaps with high-quality data,” Dr. Patil says.

Study design. While randomized control trials (RCTs) are still the best approach, there may be other research alternatives. Quasi-experimental design, for example, offers advantages beyond randomized control trials and may even speed up the research process. Using multiple sources of evidence and understanding limitations of any study design can better inform clinical practice.

“Among OSA patients with symptoms, it can be ethical to do randomized control trials as long as there’s equipoise among trial participants for the specific outcomes being studied and certain controls are in place,” Dr. Patil says. “We want to be sure safety is maximized and that we provide meaningful and informed consent.”

Improve practicality of RCT studies. “Our studies need to be patient centered,” says Dr. Patil. “When designing trials, we should consider the length of the trial and the minimum number of participants needed to appropriately answer our questions. We also want to minimize patient barriers to participation, such as travel time or the need to miss work. To build trust, we need to be clear on the intent of each study.”

Compare CPAP to other treatments. Depending on the specific research questions to be answered, it may be helpful to compare the effectiveness of CPAP therapy to other treatments, rather than to a control group.

A Significant Need

“We estimate at least 425 million people in the world have moderate to severe OSA, so we hope the workshop encourages funding agencies to look at some of these alternative approaches when deciding whether to support CPAP clinical trials,” says Dr. Patil. “We believe the ATS results will help investigators in designing future studies and facilitate agency approval of proposed studies.

“The AHRQ report demonstrates there’s a dearth of high-quality evidence that CPAP improves long-term outcomes in patients with OSA, although we know CPAP clearly improves sleepiness. This important outcome may not be well understood when only looking at the AHRQ report. Ultimately, we need additional studies, and we need funding agencies to invest in research so we can better understand CPAP effectiveness.”

For more information about CPAP therapy or the ATS Workshop, call Dr. Patil at 216-844-3201 or email Susheel.Patil@UHhospitals.org.

Contributing Expert:
Susheel Patil, MD, PhD
Director, Sleep Medicine
University Hospitals Cleveland Medical Center
Clinical Associate Professor
Case Western Reserve University School of Medicine