P066 Sleep–wake state discrepancy profiles: insomnia, sleep apnoea, and sub-clinical sleepers

Abstract Growing evidence suggests sleep–wake state discrepancy (SWSD) occurs in presentations other than insomnia, like obstructive sleep apnoea (OSA) and co-morbid insomnia and OSA (COMISA). This study investigated SWSD-profiles in insomnia and/or OSA presentations. Using a sample of sleep-clinic patients that completed polysomnography (laboratory or ambulatory) and sleep diary, SWSD was measured for sleep onset latency (SOL), wake after sleep onset (WASO), and total sleep time (TST). Insomnia Severity Index (ISI) and Apnoea-Hypopnoea Index (AHI) facilitated group categorisation: Insomnia: ISI ≥ 15, AHI < 15 (n = 48), COMISA: ISI ≥ 15 (n = 31), AHI ≥ 15, OSA: ISI < 15, AHI ≥ 15 (n = 31), Subclinical: ISI < 15, AHI <15 (n = 25). SWSD scores are presented as: (Median minutes (Inter Quartile Range)). Kruskal-Wallis H-test assessed between group differences. For SOL, Insomnia-group (13mins (44)) and COMISA-group (16mins (56) reported greater SWSD compared to OSA-group (-1.5mins (38)) and Subclinical-group (0mins (18)); (X2(3) = 11.03, p .012), mean ranks (MR): 78.54 (Insomnia-group), 76 (COMISA-group), 56 (OSA-group), 54 (Subclinical-group). For WASO, OSA-group (-49mins (79)) reported greater SWSD compared to Insomnia-group (-5mins (49)), COMISA-group (-11mins (63)), and Subclinical-group (-8mins (64)); (X2(3) = 12.902, p .005), MR: 76 (Insomnia-group), 73 (COMISA-group), 46 (OSA-group), 73 (Subclinical-group). For TST, though in opposite directions, Insomnia-group (-21mins (78)) and OSA-group (51mins (94)) reported greater SWSD than COMISA-group (-11mins (135)) and Subclinical-group (0mins (51)); (X2(3) = 16.593, p<.001), MR: 57 (Insomnia-group), 62 (COMISA-group), 93 (OSA-group), 66 (Subclinical-group). SWSD-profile varies by sleep presentation. Insomnia may report worse sleep; OSA-only may report better sleep. Other factors influencing SWSD-profiles beyond sleep presentation should be explored (e.g., sex differences, moderators).