Obstructive Sleep Apnea in Women Likely Underestimated, Undertreated

By Marilynn Larkin

December 06, 2019

NEW YORK (Reuters Health) - Current criteria for obstructive sleep apnea (OSA) "obscure" its prevalence in women and likely lead to undertreatment, researchers say.

When OSA was defined as at least 15 apnea-hypopnea events with at least 4% desaturations (AHI4P) per hour, per current U.S. Medicare guidelines, the prevalence in men was 92% higher than in women, their study suggested. But inclusion of 3%-desaturations and arousals for respiratory events - per guidelines from the American Academy of Sleep Medicine - led to significantly smaller male-female differences.

During REM sleep, OSA was similar in men and women regardless of event desaturation criteria.

"We were surprised that the severity of sleep apnea was nearly identical in men and women in REM sleep," Dr. Susan Redline of Brigham and Women's Hospital in Boston.

"The findings suggest that guidelines should include lower levels of desaturation (3%) for identifying apneas and hypopneas so as not to differentially underestimate disease in women," she added.

For the study, polysomnography data were analyzed from 2,057 participants in a multi-ethnic study of atherosclerosis. The mean age was 68.5 and 54% were women.

As reported in the journal Sleep, when OSA was defined as at least 15 AHI4P per hour, it was identified in 41.1% of men and 21.8% of women. But when events with at least 3% desaturation or arousal were added, the estimated average apnea-hypopnea index (AHI) increased by 83.7% (from 10.4 to 19.1) in women, but only by 64.2% (from 17.6 to 28.9) in men.

During REM sleep, AHI4P ≥15/h was observed in 57% of men as well as women.

During non-REM (NREM) sleep, however, AHI4P in men was 2.49 times that in women. Women also demonstrated lower loop gain, less airway collapsibility, and lower arousal threshold in NREM sleep.

Further, endotypes explained 30% of the relative sex differences in NREM-AHI4P.

Summing up, the authors state, "Protective mechanisms during NREM sleep do not substantively protect women from airway collapse during REM sleep. The relatively high REM-AHI in women is of clinical significance given growing evidence of the association between REM-OSA and adverse cardiovascular outcomes. Since current guidelines do not directly address REM-AHI for treatment, our data suggest women may be disproportionately under-treated for OSA based on the total AHI, which predominantly reflects NREM-AHI."

Dr. Redline said, "Clinicians should be sensitive to the fact that findings were from home sleep studies and may particularly underestimate sleep apnea in women. They should consider lab-based tests in women with symptoms of sleep apnea who have a 'negative' home study. The findings also point to the need to look at severity of sleep apnea not only across the night but in REM sleep."

"We will be looking at whether different treatments for sleep apnea (CPAP, medications, etc.) have different effectiveness in men versus women," she added.

Dr. Reena Mehra, Director of Sleep Disorders Research at Cleveland Clinic in Ohio, commented in an email to Reuters Health, "This is a very important study in the context of a fairly recent imperative from the US NIH/NHLBI to better understand sex-specific differences in presentation and outcomes of sleep disorders."

"The authors generated data of high clinical relevance," she said. "Therefore, our current approach of characterizing OSA more globally may need to be different in women - i.e., consider defining and treating REM-related OSA in women even if globally the sleep study findings appear to be normal."

SOURCE: http://bit.ly/2RtT6VY Sleep, online November 5, 2019.

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