https://orcid.org/0000-0003-1278-6349
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Abstract
Objective
Evaluate the concordance between overall and positional oxygen desaturation indices (ODI) and apnea-hypopnea indices (AHI) according to two different definitions for positional obstructive sleep apnea (POSA).
Methods
A total of 184 in-home polysomnograms were edited to simulate Level III home sleep apnea tests (HSAT) with the auto-scored AHI and ODI based on recording time. POSA was determined using 132 records with an AHI≥5 and at least 20 mins of recording time in both supine and non-supine positions. POSA was defined independently for the AHI and ODI based on ratios of overall/non-supine event/h ≥1.4 (O/NS) and supine/non-supine event/h≥2.0 (S/NS).
Results
Correlation between the AHI and ODI was 0.97 overall, 0.94 for supine, and 0.96 for non-supine recording times (all p<0.001). For most records, differences between the AHI and ODI were small, with only 14% of the records having a AHI-ODI difference exceeding >5/hr, and 6% exceeding >10 events/hr. The positive and negative percent agreements were uniformly good to excellent across varying clinical POSA cutoffs; percent agreements (positive, negative) were: AHI≥5=0.99, 0.78; AHI≥10=0.96, 0.89; and AHI≥15=0.96, 0.89. Cohen’s Kappa scores also showed substantial agreement for overall as well as supine and non-supine positions across varying clinical cutoffs of the AHI. Frequency of POSA was reproducibly uniform between 59% and 61% for both POSA criteria. When the O/NS and S/NS definitions conflicted in POSA characterization, O/NS was superior for identifying patients who might exhibit a greater response to supine restriction positional therapy.
Conclusions
Auto-scored positional oximetry is a clinically viable alternative to an auto-scored Level III HSAT AHI in the characterization of POSA based on a 3% desaturation.
Acknowledgments
The authors wish to thank Marija Stevanovic-Karic for her statistical support, and Ali Maree Davies and Dr Mark Levi from the Levi’s Sleep Clinic, West Gosford, NSW, Australia for their efforts in the acquisition of the PSG2 records. Dr St. Louis received research support from the National Center for Research Resources and the National Center for Advancing Translational Sciences, NIH, through Grant Number 1 UL1 RR024150-01, and the Mayo Clinic Alzheimer’s Disease Research Center Grant Award from the NIA (P50 AG016574). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.
Abbreviation list
AAI, autonomic activation index; AHI, apnea-hypopnea index; BMI, body mass index; BPM, beats per minute; CPAP, continuous positive airway pressure; HSAT, home sleep apnea test; IQR, inter-quartile range; O/NS, overall divided by non-supine events/h; ODI, oxygen desaturation index; OSA, obstructive sleep apnea; POSA, positional obstructive sleep apnea; S/NS, supine divided by non-supine events/h; SpO2, peripheral capillary oxygen saturation.
Ethics approval
This study complied with the Declaration of Helsinki with IRB approval for analysis of the deidentified records without patient consent obtained from the BioMed IRB San Diego, CA. The approval was based on the described oversight, proposed data analyses, and description of co-authors/sub-investigators provided in Protocol ABM717. The confidentiality of the patient data was maintained throughout the study.
Author contributions
All authors made substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; took part in drafting the article or revising it critically for important intellectual content; gave final approval of the version to be published; and agree to be accountable for all aspects of the work.
Disclosure
Mr Levendowski and Dr Westbrook are shareholders in Advanced Brain Monitoring, Inc. and would benefit financially if the intellectual property for the Sleep Profiler, Night Shift, and/or Positional Sleep Assessment System was acquired by a third party. Mr Levendowski and Dr. Westbrook have the following patents issued to Advanced Brain Monitoring: US 8783264, US 9198615, US 9855006, US 8355769 and US 8639313. Dr Hamilton reports they have received equipment to support research projects from Resmed, Philips Respironics and Air Liquide Healthcare. Dr St. Louis report grants from NIH NHLBI, NIA, NINDS, Michael J. Fox Foundation and Sunovion, Inc., outside the submitted work. Dr St. Louis is on the Adverse Events Adjudication and Data Safety Monitoring Board for Clinical Trial for Inspire, Inc. Dr Penzel report grants from Itamar, Cidelec, Resmed, Löwenstein Medical and grants and personal fees from Philips/Respironics, during the conduct of the study; grants from Cidelec, Itamar, Resmed, Löwenstein Medical and grants and personal fees from Philis/Respironics, outside the submitted work. Dr Dawson reports personal fees from consultancy with Philips Respironics, personal fees from Managing Director of OSA Risk Management Ltd and personal fees from being a shareholder in Sleep Doctor Ltd, outside the submitted work. The authors report no other conflicts of interest in this work.