From the Journals

New hypopnea criteria ID unique OSA patient subset

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Useful take on varying hypopnea definitions

The study by Won and colleagues provides a “useful perspective” on how hypopnea is defined by including outcome data based on the two different scoring criteria, according to Kenneth R. Casey, MD, MPH, and Rachna Tiwari, MBBS.

Results of the study suggest a rationale for using both the 2007 American Academy of Sleep Medicine hypopnea criteria based on ≥ 4% desaturation, and the updated 2012 AASM criteria based on ≥ 3% desaturation or arousal in the evaluation of polysomnography results, Dr. Casey and Dr. Tiwari said in a commentary accompanying the study.

“This perspective may ultimately be the solution to the confusion caused by competing functional definitions of hypopnea,” they said in the commentary published in the Journal of Clinical Sleep Medicine.

The 2007 recommended criteria of ≥ 4% desaturation seemed reasonable based on available evidence at the time, but was not rigorously based by today’s standards, the authors said.

At that time, they also proposed the new alternative criteria based on ≥ 3% desaturation or an arousal, which in 2012 became elevated to a recommended rule. However, the previous recommended rule was kept to accommodate patients who required Centers for Medicare & Medicaid Services reimbursement, according to Dr. Casey and Dr. Tiwari.

Subsequent studies demonstrated “significant differences” in apnea-hypopnea index results, depending on which scoring criteria were used, they added.

“This confusing, vacillating definition has created a rather bizarre, and perhaps unsettling, situation wherein the severity of the diagnosis of sleep-disordered breathing, and perhaps its presence or absence, is determined by the patient’s insurance coverage,” they said in the commentary.

Dr. Casey and Dr. Tiwari are with the University of Wisconsin and William S. Middleton Memorial Veterans Hospital, both in Madison. They reported no conflicts of interest related to their editorial, which appears in the Journal of Clinical Sleep Medicine.


 

FROM THE CLINICAL JOURNAL OF SLEEP MEDICINE

The latest recommended criteria for hypopnea define a distinct group of patients who report substantial daytime sleepiness but with no significant cardiovascular risk, investigators reported in a retrospective, cross-sectional analysis.

Dr. Christine Won of Yale University, New Haven, Conn. Andrew D. Bowser/MDedge News

Dr. Christine Won

The number of obstructive sleep apnea (OSA) diagnoses increased by nearly 13% when using the 2012 American Academy of Sleep Medicine (AASM) criteria of ≥ 3% desaturation or arousal, instead of the 2007 criteria of ≥ 4% desaturation, according to investigators.

While cardiovascular disease risk did not appear to be elevated in those with an OSA diagnosis based on the newer, more inclusive criteria, the OSA diagnosis remained a significant risk factor for arrhythmias in this group of patients, reported lead author Christine H.J. Won, MD, of Yale University, New Haven, Conn., and her coinvestigators.

“Our findings suggest [that] a more inclusive hypopnea definition alters OSA severity categorization, identifies a new symptomatic group of patients with predominantly mild OSA without increased cardiovascular odds, and does not ameliorate the increased odds predicted by severe OSA for arrhythmias,” the investigators wrote in the Journal of Clinical Sleep Medicine.

The analysis by Dr. Won and her colleagues included 1,400 veterans who had polysomnography for suspected sleep-disordered breathing. Of those veterans, two-thirds (932; 66%) had an OSA diagnosis based on the ≥ 4% desaturation criteria.

With the newer criteria of ≥ 3% desaturation or arousal, another 175 OSA diagnoses were captured out of the remaining 468 previously negative studies, meaning that more than 37% of those patients would be recategorized as having OSA, Dr. Won and her coauthors said.

Compared with individuals with OSA classified by the older, more restrictive criteria, the 175 individuals in this “new OSA” group were younger and less likely to be obese, though they were still more likely to be obese, compared with individuals with no OSA diagnosis, according to the authors.

The new OSA group had more disrupted sleep architecture, significantly worse oxygen saturations, and more self-reported sleepiness on the Epworth Sleepiness Scale as compared with those with no OSA, they added.

Adding in the new OSA group redistributed disease severity, with a relative increase of 21.4% for mild and 21.3% for moderate OSA, but just 15.3% for severe OSA. “Most of the [new OSA] category consisted of mild sleep-disordered breathing,” said Dr. Won and her coauthors in the report.

While there was a statistically significant increase in odds ratio for arrhythmias using the older criteria, reclassifying OSA severity using the newer definition meant that mild and moderate disease lost predictive value. However, severe OSA by the new criteria remained a significant predictor of arrhythmias, the authors said.

Odds ratios for ischemic heart disease and heart failure were numerically higher in the new OSA group versus the no OSA group, though no statistically significant differences were found, according to investigators.

This is thought to be the first study to describe a unique group of patients who escape OSA diagnosis based on the ≥ 4% desaturation criteria but are captured ≥ 3% desaturation or arousal criteria, Dr. Won and her coauthors said.

Further studies would be helpful to evaluate other polysomnographic features in this group to see how they affect cardiovascular or other health risks, they added.

“It would also be important to assess whether treatment in any of these groups leads to improved cardiovascular health, or whether treatment of the [new OSA] group leads to improved daytime sleepiness or quality of life,” they said in the report.

The researchers reported no conflicts of interest related to their work, which was performed at the Veterans Affairs Healthcare System in West Haven, Conn.; Indianapolis; and Cleveland.

SOURCE: Won CHJ et al. J Clin Sleep Med. 2018 Dec 15;14[12]:1987-94.

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