The prevalence of REM-related obstructive sleep apnoea is reduced by the AASM 2012 hypopnoea criteria

Purpose: The variations in reported prevalence of Rapid eye movement-related obstructive sleep apnea (REM-OSA) have been attributed to different definitions, although the effect of hypopnea criteria has not been previously investigated.Methods: Within this retrospective study, 134 of 382 consecutive patients undertaking polysomnography (PSG) for the suspicion of OSA met the inclusion criteria. PSGs were scored using both the 2007 AASM recommended hypopnea criteria (AASM2007Rec) and the 2012 AASM recommended hypopnea criteria (AASM2012Rec). For each hypopnea criteria, REM-OSA patients were grouped as REM-related [either as REM-predominant OSA (rpOSA) or REM-isolated OSA (riOSA)] or non-stage specific OSA (nssOSA). Outcome measures (SF-36, FOSQ and DASS-21) were also compared between groups.Results: Incorporation of the AASM2012Rec criteria compared to the AASM2007Rec criteria increased the Apnea-Hypopnea Index (AHI) for NREM and REM sleep but decreased the ratio of the REM AHI: NREM AHI from 1.9 to 1.3 (p<0.001). It also decreased the prevalence of riOSA [15.7% vs 2.2% (p<0.001) for AASM2007Rec and AASM2012Rec respectively]. The prevalence of rpOSA remained the same for each hypopnea criteria although the prevalence of nssOSA increased with the AASM2012Rec hypopnea criteria [53.0% vs 66.4% (p