A266 SLEEP, Volume 46, Supplement 1, 2023 Abstract citation ID: zsad077.0606 0606 FATIGUE OR EXCESSIVE DAYTIME SLEEPINESS, WHICH IS MORE RELATED WITH DEPRESSION? Kwang Ik Yang 1 , Soo Hwan Yim 2 , Seung Cheol Lee 1 , Daeyoung Kim 3 , Min Kyung Chu 4 , Chang-Ho Yun 5 1 Sleep Disorders Center, Department of Neurology, Soonchunhyang University College of Medicine, Cheonan Hospital, 2 Department of Neurology, Ulsan University, College of Medicine, Gangneung Asan Hospital, 3 Department of Neurology, Chungnam National University College of Medicine, 4 Department of Neurology, Severance Hospital, Yonsei University, College of Medicine, 5 Department of Neurology, Bundang Clinical Neuroscience Center, Seoul National University Bundang Hospital Introduction: Fatigue and excessive daytime sleepiness (EDS) were often regarded as having almost similar meaning in routine daily life. However, these two terms are strictly distinct concepts. The effect on depression between EDS and fatigue, which coexist depending on the situation or exist individually. We aimed to inves- tigate both fatigue and EDS were classifed in detail to determine which is more related to depression in the general population. Methods: A total of 2,493 participants (female: 1,257) (47.90 ± 0.33 years old) were investigated nationwide, across 15 South Korean districts using face-to-face interviews survey. Fatigue, EDS, and depression were evaluated using the Fatigue Severity Scale (FSS), Epworth sleepiness scale (ESS), and Patient Health Questionnaire-9 (PHQ-9), respectively. The covariates such as sleep habits and socio-behavioral factors were included. Results: The prevalence of depression (PHQ-9 ≥ 10) was 8.42% (n = 210). Fatigue (FSS ≥ 36) was 30.8% (n = 767). EDS (ESS ≥ 11) was 15.3% (n = 382). The prevalence of depression was following four categories; EDS with fatigue (E+F+) (n = 67, 31.9% vs. 7.3%) (P < 0.001), fatigue without EDS (E-F+) (n = 71, 33.8% vs. 20.3%) (P < 0.001), EDS without fatigue (E+F-) (n= 16, 7.6% vs. 5.8%) (P = 0.294), and absence of fatigue and EDS (E-F-) (n = 56, 26.7% vs. 66.6%) (P < 0.001). After adjusting for covariates, the presence of depression (E-F-, reference) was associated with E+F+ (OR 8.804, 95% CI 5.818-13.321), E-F+ (OR 3.942, 95% CI 2.704-5.747), and E+F- (OR 2.812, 95% CI 1.542-5.131). We additionally performed logistic regression according to two categories. There was no signif- icant difference of prevalence of depression between E+F- (refer- ence) and E-F+ (OR 1.399, 95% CI 0.760-2.575). Conclusion: Although fatigue and EDS were associated with depression regardless of the presence of each other. But we did not fnd out which is more related with depression. Support (if any): Abstract citation ID: zsad077.0607 0607 IMPROVEMENT IN SLEEP LATENCY WITH FT218 (ONCE-NIGHTLY SODIUM OXYBATE): ANALYSIS FROM THE PHASE 3 REST-ON CLINICAL TRIAL Michael Thorpy 1 , Colin Shapiro 2 , Clete Kushida 3 , Maurice Ohayon 3 , Jordan Dubow 4 , Jennifer Gudeman 4 1 Montefiore Medical Center, 2 University of Toronto, 3 Stanford University School of Medicine, 4 Avadel Pharmaceuticals Introduction: In the phase 3 REST-ON trial (NCT02720744), mean sleep latency on the Maintenance of Wakefulness Test (MWT) was signifcantly improved vs placebo with investiga- tional, extended-release once-nightly sodium oxybate (FT218 [ON-SXB]; P< 0.001). This post hoc analysis assessed response to treatment and improvement in excessive daytime sleepiness (EDS). Methods: Participants (≥16 years) with narcolepsy type 1/2 were randomized 1:1 to double-blind ON-SXB or placebo. Doses were 4.5 g week 1, 6 g weeks 2‒3, 7.5 g weeks 4‒8, and 9 g weeks 9‒13. Mean sleep latency on the MWT was measured in 5 tri- als up to 30 minutes each at baseline and weeks 3, 8, and 13. Percentage of participants with improvement of ≥5, ≥10, ≥15, and ≥20 minutes from baseline and with mean sleep latency=30 minutes were assessed. Two-sided P values were calculated using Fisher exact test. Results: The modifed intent-to-treat population included 190 participants (ON-SXB, n=97; placebo, n=93). At baseline, mean (SD) sleep latency was as follows: ON-SXB, 5.0 (3.1) minutes; placebo, 4.7 (2.6) minutes. More participants receiving ON-SXB vs placebo had mean MWT=30 minutes at weeks 3 (6 g; 5.7% vs 0%; P< 0.05), 8 (7.5 g; 10.5% vs 1.3%; P< 0.05), and 13 (9 g; 13.2% vs 5.1%; P=0.14). A signifcantly greater percentage of participants receiving ON-SXB vs placebo had improved mean sleep latency ≥5 to ≥20 minutes over baseline at all doses (6 g: ≥5 min, 57.5% vs 25.0%; ≥10 min, 35.6% vs 9.1%; ≥15 min, 18.4% vs 3.4%; ≥20 min, 10.3% vs 1.1% [all P< 0.01]; 7.5g: ≥5 min, 63.2% vs 28.2%; ≥10 min, 43.4% vs 11.5%; ≥15 min, 31.6% vs 3.8%; ≥20 min, 15.8% vs 1.3% [all P< 0.001]; 9 g: ≥5 min, 66.2% vs 37.2% [P< 0.001]; ≥10 min, 50.0% vs 19.2% [P< 0.001]; ≥15 min, 32.4% vs 10.3% [P< 0.01]; ≥20 min, 17.6% vs 6.4% [P< 0.05]). Conclusion: Clinically signifcant improvements in EDS occurred with 6-, 7.5-, and 9-g doses of ON-SXB. At the 2 high- est doses, >10% of participants remained awake for the entire MWT. If ON-SXB is granted FDA approval, adults with narco- lepsy will have a once-nightly treatment to improve EDS. Support (if any): Avadel Pharmaceuticals Abstract citation ID: zsad077.0608 0608 PAX8/PAX8-AS1 DNA METHYLATION LEVELS ARE NOT ASSOCIATED WITH SLEEP DURATION IN MEDICATED PATIENTS WITH UNEXPLAINED HYPERSOMNOLENCE Andy Madrid 1 , Ligia Papale 1 , Jesse Cook 1 , Kieulinh Tran 1 , Michael Prairie 2 , Ana Maria Vascan 1 , Reid Alisch 1 , David Plante 1 1 University of Wisconsin-Madison, 2 University of Minnesota Introduction: The biological basis of daytime sleepiness and excessive sleep duration in patients with unexplained hyper- somnolence is unknown. However, a growing body of evidence suggests modulations in the epigenome coincide with objective measures of sleep, suggesting epigenetic mechanisms may be related to hypersomnolence. Previously, we identifed signifcant correlations between saliva DNA methylation abundance at nine CpG sites located in the PAX8/PAX8-AS1 genes and total sleep time measured using polysomnography in unmedicated, clinical patients with unexplained hypersomnolence. Since psychotropic medications frequently affect clinical sleep testing and may also affect DNA methylation, here we attempted to replicate prior fndings in a separate, medicated sample. Methods: Forty-three medicated clinical patients with unex- plained hypersomnolence were drawn from a larger study of a multimodal sleep assessment that included ad libitum overnight B. Clinical Sleep Science and Practice III. Hypersomnia Downloaded from https://academic.oup.com/sleep/article/46/Supplement_1/A266/7182254 by guest on 31 May 2023