0475 Optimal Thresholds for Split-Night Polysomnography with Transitions in Laboratory Hypopnea Scoring Criteria

Abstract

Abstract Introduction Performance of split-night polysomnography, the application and titration of positive airway pressure (PAP) therapy after an initial diagnostic interval, is a common practice in clinical sleep medicine. There is no currently recommended apnea-hypopnea index (AHI) threshold at which PAP should be applied during polysomnography. Differences in American Academy of Sleep Medicine (AASM) and Centers for Medicare and Medicaid Services (CMS) hypopnea scoring criteria and limitations on real-time hypopnea classification complicates identification of an optimal split-night threshold. Of particular concern is that patients may be “split” under AASM hypopnea rules but have insufficiently severe sleep disordered breathing under CMS rules to be diagnosed or treated appropriately. This study aimed to clarify optimal AHI thresholds for split night polysomnography in the context of a laboratory-wide transition from CMS to AASM hypopnea scoring criteria. Methods Effective October 1, 2021, our laboratory transitioned solely to scoring AASM-defined hypopneas, with additional post hoc identification of CMS hypopneas for reporting purposes. With this change, the split-night threshold was changed from 15 to 30/hr. All diagnostic polysomnograms (without PAP therapy) performed on adult patients through October 31, 2022, were retrospectively analyzed to clarify the effect of changing hypopnea scoring criteria in this context. Results 634 diagnostic polysomnograms were analyzed. An AHI threshold of 15/hr (using AASM hypopnea criteria) in the first two hours of sleep with at least 3 hours of time remaining for PAP titration would have resulted in 96 additional patients receiving treatment with PAP therapy. Among these, only one (1.04%) had CMS AHI below 5/hr. Sixty-eight of these patients had CMS AHI 5-15/hr during the first two hours of sleep. Among these, only eight patients did not have an additional comorbidity or symptom profile under CMS guidelines making them eligible for PAP therapy, however, none had CMS AHI >15/hr when the full night of sleep was analyzed. Conclusion Our study suggests there is little need to raise the split-night threshold when transitioning from CMS to AASM hypopnea criteria, and doing so substantially reduces the number of patients treated with PAP therapy in the sleep laboratory. Support (if any) None