Better OSA assessment methods needed after study finds 1 in 5 misdiagnosed on single-night study


By Natasha Doyle

17 Jan 2022

Australian respiratory researchers are pitching a new approach to sleep apnoea detection after finding one in five people may be misdiagnosed in single-night studies.

The home-based method uses under-mattress sensor technology to track respiratory events over several nights, giving physicians a clearer picture of patients’ sleep apnoea status and potentially, a way to monitor the efficacy of therapeutic interventions.

It was recently assessed in 67,278 Withings Sleep Analyzer users with 11.6 million nights of data. The investigation found 14 nights of testing was optimal for identifying obstructive sleep apnoea (OSA) severity, while one-night studies could misclassify 20% to 50% of patients. It also indicated around 20% of patients had moderate-to-severe OSA, experiencing at least 15 respiratory disturbances per hour of sleep.

“Prior to recent advances in non-invasive home sleep monitoring technology, it was not feasible to examine night-to-night variation in OSA severity and its potential impact on diagnostic classification and prevalence estimates over extended periods in the home setting at scale,” Flinders University Research Associate Mr Bastien Lechat and colleagues wrote in the American Journal of Respiratory and Critical Care Medicine.

Poor OSA management has been associated with adverse health and safety consequences including increased cardiovascular disease risk, depression, traffic accidents, reduced quality of life and all-cause mortality, Mr Lechat and his team noted.

Though the home-based, multi-night approach doesn’t “preclude the need for gold-standard polysomnography”, it may be a feasible, cost-effective and complementary way to improve diagnostic accuracy and access to care, they suggested.

Other devices

However, while the under-mattress device may be a “useful research tool in trying to understand [long-term] health effects of sleep apnoea”, Sydney University Professor of Sleep Medicine Ron Grunstein suggested other devices could offer similar diagnostic information in shorter periods of time.

“There are devices out there that you can use for three nights that probably give you pretty close to that information [obtained from 14 days’ testing with the under-mattress device],” he told the limbic.

Professor Grunstein already uses a multi-night approach to testing, saying that “[he runs] a clinic with severe mental illness and sleep disorders and [does] three nights of oximetry, you know, as a sort of screening test”.

OSA severity can change nightly based on body position, environmental effects, alcohol and medication use and manual, in-laboratory measurement may be affected by interscorer variability. This is “particularly problematic for arousal and hypopnea quantification”, the study authors wrote.

Where the non-invasive under-mattress sensors avoid this variability, deriving scores from objective, pre-set criteria and acquired physiological signals, they have fewer input variables for detecting and differentiating between types of respiratory events than more extensive, direct and invasive polysomnography.

The latter is especially helpful in “complex cases or in people with major or multiple comorbidities where additional information on hypoxemia and OSA endotypes may be clinically indicated and informative”, the authors wrote.

But even with these tools, “I think the authors of the study would agree to that, just having lots of numbers is not enough”, Professor Grunstein said.

“In the end we’ve got to be very careful to look at the patient themselves rather than the mattress,” he said, adding that he could see wider-adoption of these under-mattress technologies, so long as they’re “unobtrusive, keep working and have no technical issues”.

“We’ll see over the next few years how these devices actually fit in, but I think, for example, if they could come up with a reliable mattress-based device to look at sleep quality, and you know patients with insomnia, you know that would also be very good to monitor treatment — probably more important than sleep apnoea.

Overall though, multi-night approaches could be “invaluable for clinical trials both in terms of assessing eligibility criteria and for long-term monitoring of therapeutic interventions”, the study authors wrote.

The findings “highlight the need to consider night-to-night variation on OSA diagnosis and management” and support the use of non-invasive, home-based, multi-night monitoring, they concluded.

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