Using apneas and hypopneas compared with apneas only affects the classification of predominant obstructive sleep apnea (OSA) significantly among patients who are hospitalized for atrial fibrillation (AF), according to a retrospective study published in Sleep Medicine.

Investigators performed a retrospective analysis of data from patients with AF and preserved ejection fraction to determine the classification of sleep-disordered breathing (SDB) by using either apneas and hypopneas or apneas only. A total of 211 patients were included in the final analysis (146 men; mean age, 68.7±8.5 years).

Overall, hypopneas represented >50% of all respiratory-related events. Based on apneas only, approximately 44% of patients had predominant central sleep apnea (CSA) and 46% of patients had predominant OSA. The proportion of patients with OSA was higher (56%) based on both apneas and hypopneas.

In addition, the proportion of patients with CSA was lower based on the apnea and hypopnea classification system (36%). The researchers then analyzed a subgroup of patients with moderate to severe SDB and found that based on apneas only, predominant CSA was present in 55.2% of patients vs 42.1% with apneas and hypopneas.

Patients included in this study were receiving treatment at a tertiary care center, limiting the ability to apply these results to patients in primary care centers. Investigators also suggested that the potential failure in capturing all patients during the screening process represented an additional limitation of the study.

“To our knowledge, there are no data available on whether apneas and hypopneas have a different prognostic effect in patients with [AF],” the investigators wrote. “It is possible that the extent of hypoxemia, arousals, and autonomic nervous system activation could be comparable, suggesting that the inclusion of hypopneas in any classification system is important.”

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Strotmann J, Fox H, Bitter T, et al. Predominant obstructive or central sleep apnea in patients with atrial fibrillation: influence of characterizing apneas versus apneas and hypopneasSleep Med. 2017;37:66-71.