Pneumology - Original Articles Open access

Agreement between apnea-hypopnea index and hypoxic burden for severity classification of obstructive sleep apnea

Authors

Published
26 August 2026
Issue
Early Access
Section
Pneumology - Original Articles
DOI
10.4081/monaldi.2026.4016

Abstract

This study aimed to evaluate the agreement between apnea-hypopnea index (AHI)- and hypoxic burden (HB)-based obstructive sleep apnea (OSA) severity classifications. A retrospective single-center study of adults aged 18-79 years undergoing full-night in-laboratory polysomnography was conducted. OSA severity by AHI was categorized as normal (<5 events/hour), mild (5 to <15), moderate (15 to <30), or severe (≥30). HB severity was categorized as mild (<3.34), moderate (3.34 to 6.66), or severe (≥6.67). Agreement among patients with OSA (AHI ≥5) was assessed using Cohen’s kappa. Ninety-five patients were included (mean age 58.4±18.3 years); 73 (76.8%) had OSA. Among these, HB severity exceeded AHI severity in 27.4%, was concordant in 61.6%, and was lower in 11.0%. Observed agreement was 30.1%, with slight concordance beyond chance (κ=0.168, p<0.001). Continuous AHI and HB were moderately correlated (r=0.663, p<0.001). Patients with HB greater than AHI severity demonstrated significantly lower nadir oxygen saturation (p=0.011). AHI- and HB-based OSA severity classifications demonstrate limited agreement. Incorporation of HB may provide a more physiologically informative assessment of OSA severity beyond event frequency alone.

Keywords

Ethics Approval

Ethical approval was obtained from the Ethical Review Committee of the Baptist Hospitals of Southeast Texas, Texas, United States (Protocol # BHSET23.035). The study was performed in accordance with the ethical standards outlined in the 1964 Declaration of Helsinki and its future amendments.

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