Sleeping with a continuous positive airway pressure (CPAP) machine is the most effective treatment for sleep apnea, but getting patients to use these devices consistently remains a major challenge. Now, a development by scientists at the University of Chicago Medicine and Northwestern University provides patients and physicians with a new tool for monitoring treatment adherence.
For the study, researchers designed an app to track CPAP use, along with sleep tracking and other health metrics. The idea behind the design was simple: While current guidelines describe the use of CPAP for at least 4 hours per night as adequate, the researchers believe that the amount of treatment patients need per night will vary from person to person, as it should be closely related to the number of hours they sleep.
“Sleep apnea can only be effectively treated if CPAP is used throughout the entire sleep period in bed,” said Esra Tasali, MD, director of the Sleep Center at the University of Chicago and the paper’s senior author. “We know that sleep patterns can vary widely, so one-size-fits-all adherence guidelines are not enough for most patients. By developing a personalized CPAP treatment tool for sleep apnea, we provide patients and providers with An opportunity for them to deliver and track treatment based on individual needs.”
The study was published Dec. 5 in the Journal of Medical Internet Research.
CPAP needs vary from person to person
The tool provides a new adherence metric: the percentage of time users wear a CPAP relative to their objectively assessed sleep time. This allows treatment to be tailored to the patient’s needs on a nightly basis. The new metric provides significantly different information about adherence success compared to traditional CPAP tracking methods, which only report hours spent wearing a CPAP mask and do not account for hours of sleep without a mask.
Sleep apnea affects an estimated 54 million U.S. adults and 1 billion people worldwide. Left untreated, sleep apnea has been linked to serious health conditions, including high blood pressure, heart disease, stroke and diabetes, and increases the risk of car accidents and work-related injuries due to sleepiness and decreased alertness.
CPAP machines work by delivering constant air pressure through the nose or mouth to keep the upper airway open during sleep. “CPAP adherence remains a major challenge,” Tasali said. “It is estimated that about half of patients do not adhere to treatment.”
Patients often inadvertently remove their CPAP devices during the night, possibly due to discomfort. Telling patients that four hours of CPAP a night is enough to treat their sleep apnea is “arbitrary and misleading,” Tasali said.
“Despite a lack of strong evidence that it is sufficient or has a clear benefit on health outcomes, the guidelines are still commonly used today,” she said.
Unlike other therapies, such as medication, that continue to treat health problems for hours after delivery, CPAP therapy is only effective when used during sleep. This means that for a patient who sleeps only four hours, wearing a CPAP for four hours may be an adequate “dose”, but a patient who sleeps eight hours receives half the therapeutic dose.
“The goal of treatment should be to use the device 100 percent of the time in bed,” Tasali said. “By integrating a wearable sleep tracker, our tool provides individual dosing for CPAP therapy and a more meaningful metric for compliance monitoring that could be incorporated into clinical guidelines.”
A new wearable system for tracking CPAP use
For the study, a Northwestern team led by preventive medicine professors Bonnie Spring, Ph.D., and Angela Pfammatter, Ph.D., modified a weight-loss app they developed that tracks diet, physical activity and weight. To support weight loss, mobile technology systems integrate information from wearable sleep and activity trackers and scales. Because being overweight is a major risk factor for sleep apnea, the researchers modified the app so that it charted patients’ CPAP wear time and checked it against a goal of sleeping 100 percent of the time while wearing the device.
“Patients want to see that 100% of the goals shown in the app are what they are going to achieve every night,” says Tasali.
By showing progress toward sleep goals and other icons that track progress towards diet, activity and weight goals, the app can help people see how improving one health behavior can more easily change others.
“This is important,” Spring said, “because sleep deprivation, poor diet quality, physical inactivity and being overweight often go hand in hand. Having tools and strategies that can help people change multiple risky behaviors at the same time is a huge efficiency.”
Based on patient feedback, the researchers added features like push notifications to remind users to put on their CPAP before bed. Physicians can use new CPAP tracking technology to provide more comprehensive and effective sleep apnea treatment.
“Currently, it’s difficult for providers to advise patients on how best to use their CPAP machines, or how many times per night to use them,” Tasali said. “Thus, this app can be used not only as a self-management tool for patients, but also as a more accurate and personalized method for monitoring the effectiveness of treatment for healthcare providers.”
New Tool to Understand the Health Effects of CPAP Use
As a next step, the researchers are planning more studies to test the tool against traditional methods of monitoring CPAP use to see if it can improve patients’ adherence to treatment. Additionally, Tasali hopes to study the effect of percent CPAP adherence on health outcomes such as blood pressure and blood sugar levels.
The study, “Development of a Novel mHealth Tool for Obstructive Sleep Apnea: Tracking Continuous Positive Airway Pressure Compliance as a Percentage of Bed Time,” was supported by the National Institutes of Health (R01DK120312, R01DK125749) and CPAP Devices For this study provided by ResMed. Other authors include Bonnie Olivia Hughes, Becky Tucker and Harry Whitmore of the University of Chicago.