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 apnoea (REM-OSA) have been attributed to different definitions, although the effect of hypopnoea 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 hypopnoea criteria (AASM2007Rec ) and the 2012 AASM recommended hypopnoea criteria (AASM2012Rec ). For each hypopnoea 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 apnoea-hypopnoea index (AHI) for NREM and REM sleep but decreased the AHIREM /AHINREM ratio 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 hypopnoea criteria although the prevalence of nssOSA increased with the AASM2012Rec hypopnoea criteria [53.0 vs 66.4% (p < 0.006) for AASM2007Rec and AASM2012Rec , respectively]. There were no differences in clinical symptoms between the groups, irrespective of hypopnoea criteria used.

CONCLUSIONS: This study demonstrates that in comparison with AASM2007Rec , the AASM2012Rec hypopnoea criteria reduce the prevalence of riOSA but not rpOSA by reducing the ratio of REM respiratory events and NREM respiratory events.