Purpose: To compare the apnea-hypopnea indices (AHIs) derived using three hypopnea definitions published by the American Academy of Sleep Medicine (AASM) and to determine the impact of the new modifications of the definition on AHIs and the diagnosis of obstructive sleep apnea (OSA).
Methods: The study comprised 100 consecutive patients who were investigated for OSA using overnight diagnostic polysomnography (PSG). The hypopneas were scored in three passes by two certified sleep technologists; in the first pass, the hypopneas were scored using the 2007 AASM "Alternative" (H Alt) criteria. In the second pass, the hypopneas were scored using the 2007 AASM "Recommended" (H Rec) criteria. In the third pass, the hypopneas were scored according to the new AASM "2012" (H 2012) criteria. Agreement analysis of the results obtained using the three scoring criteria was performed using the Bland-Altman plot methodology.
Results: The studied group had a mean age of 45.5±12.6 years and a body mass index of 30.2±5.8 kg/m2. Using the H 2012, H Rec and H Alt criteria, the AHIs were 37.9±27.6, 14.8±22.4 and 29.6±27.0/h, respectively (p<0.05). The Bland-Altman analysis of the AHI demonstrated that more events were nearly always detected using the H 2012 definition.
Conclusion: A significant difference in detecting hypopnea events exists among the H 2012, H Rec and H Alt definitions. The 2007 AASM "Recommended" definition tended to result in lower AHI than the other two definitions.