A transition to the American Academy of Sleep Medicine–recommended hypopnea definition in adults: initiatives of the Hypopnea Scoring Rule Task Force

The American Academy of Sleep Medicine (AASM) recommends that hypopneas be identified using a definition that is based on a ≥ 30% decrease in airflow associated with a ≥ 3% reduction in the oxygen saturation or an arousal (H3A) for diagnosis of obstructive sleep apnea (OSA) in adults. This conflicts with the Centers for Medicare & Medicaid Services definition, which requires a ≥ 4% decrease in the oxygen saturation to identify a hypopnea (H4) and does not acknowledge arousals. In 2018, the AASM Board of Directors constituted a Hypopnea Scoring Rule Task Force with a mandate to “create a strategy for adoption and implementation of the AASM recommended adult hypopnea scoring criteria among members, payers and device manufacturers.” The task force initiated several activities including a survey of AASM-accredited sleep facilities and discussions with polysomnography software vendors. Survey results indicated that most sleep facilities scored polysomnograms using only the Centers for Medicare & Medicaid Services definition. Vendors indicated that they could easily support dual scoring. Informal testing among task force members’ sleep facilities confirmed there would be little additional work if dual scoring was performed. The task force convened several meetings of a working group of OSA content experts and interested parties, with the purpose of creating research recommendations to study the impact on relevant clinical outcomes using the different definitions of hypopnea. Several possible prospective and retrospective approaches were discussed with emphasis on the group of patients diagnosed with OSA based on an apnea-hypopnea index using H3A but not H4. Based on the deliberations of the working group, the Hypopnea Scoring Rule Task Force submitted recommendations to the AASM Foundation concerning research project strategies for potential grant funding. Further discussions within the Hypopnea Scoring Rule Task Force focused on developing advocacy initiatives among patient stakeholder groups to change payer policy.