Abstract Introduction Low-sodium oxybate (LXB; Xywav®), the only FDA-approved treatment for idiopathic hypersomnia in adults, was evaluated in the phase 4, open-label DUET study (NCT05875974). This post-hoc analysis evaluated subgroups of participants with idiopathic hypersomnia stratified by patient-reported ideal nighttime sleep duration (with [>9 hours] and without [≤9 hours] long sleep need [LSN]), based on Idiopathic Hypersomnia Severity Scale (IHSS) Item 1. Methods DUET included screening, 8-day baseline (BL), 2−8-week LXB dose titration/optimization, 2-week stable-dose, 8-day end-of-treatment (EOT), and 2-week safety follow-up periods. Outcomes were Epworth Sleepiness Scale (ESS), IHSS, polysomnographic total sleep time (TST), and Patient Global Impression of Severity (PGI-S) and Change (PGI-C). Least squares mean (LSM) changes (BL-to-EOT) were BL-adjusted; P values are nominal. Treatment-emergent adverse events (TEAEs) were assessed by subgroup. Results Of 46 enrolled participants with idiopathic hypersomnia, 45 had BL IHSS data; 24 reported LSN (>9 hours) and 21 reported no LSN (≤9 hours). Most (LSN/without LSN) were female (100%/61.9%) and White (91.7%/76.2%), with mean±SD age 36.8±11.1/38.6±12.1 years; 20/24 and 19/21 completed the study. BL mean±SE (LSN/without LSN) ESS scores were 16.8±0.5/16.1±0.7; LSM changes (95% CI): LSN −9.5 (−11.5, −7.6; P< 0.0001; n=20), without LSN −7.4 (−9.4, −5.4; P< 0.0001; n=19). BL mean±SE (LSN/without LSN) IHSS total scores were 35.7±1.3/30.5±1.8; LSM changes (95% CI): LSN −18.3 (−22.4, −14.1; P< 0.0001; n=19), without LSN −12.5 (−16.9, −8.0; P< 0.0001; n=17). BL mean±SE (LSN/without LSN) IHSS long sleep/sleep inertia component scores were 12.5±0.6/9.2±0.6; LSM changes (95% CI): LSN −5.5 (−6.8, −4.1; P< 0.0001; n=19), without LSN −4.0 (−5.4, −2.5; P< 0.0001; n=17). BL mean±SE (LSN/without LSN) polysomnographic TSTs were 490.0±26.0/442.7± 24.7 minutes; LSM changes (95% CI): LSN −53.1 (−92.5, −13.7; P=0.0097; n=20), without LSN −59.4 (−99.8, −18.9; P=0.0052; n=19). On the PGI-C, most participants (LSN/without LSN) endorsed improved overall disease (100%/88.2%; n=19/n=17) at EOT. TEAEs were reported in 79.2% (LSN) and 66.7% (without LSN); most (LSN/without LSN) were mild (45.8%/42.9%) or moderate (33.3%/23.8%) in severity; 1 (without LSN) was serious (unrelated to study drug). Conclusion Participants with or without LSN (>9 hours or ≤9 hours, respectively) taking LXB showed improvements in multiple idiopathic hypersomnia symptoms and reduced TST. Support (if any) Jazz Pharmaceuticals
Shared Pathogenic Pathways Between REM Sleep Behavior Disorder and Neurodegenerative and Psychiatric Disorders
Abstract Isolated/idiopathic rapid-eye-movement (REM)-Sleep Behavior Disorder (iRBD) is characterized by dream enactment behaviors associated with loss of REM atonia. iRBD is in most cases a prodromal synucleinopathy, and emerging evidence suggests associations between RBD and other neurological and psychiatric conditions. In this study, we performed pathway-based polygenic risk score (PRS) and rare variant burden analyses to examine these potential associations. Pathway-specific PRS were constructed from genome-wide association study summary statistics of five neurodegenerative and seven psychiatric traits across 10 biologically relevant pathway categories, including a total of 279 pathways, in 1,573 iRBD cases and 16,022 controls from the International RBD Study Group and UK Biobank. Rare variant burden tests were performed in 1,264 iRBD cases and 2,581 controls. We identified multiple potential pathways indicating shared polygenic risk between RBD and both neurodegenerative and psychiatric disorders. Lewy body diseases and post-traumatic stress disorder had the most shared polygenic risk pathways in neurological and psychiatric disorders, respectively. Two pathways, the serotonin transport pathway and the chaperone-mediated autophagy pathway, showed the strongest association with iRBD, and gene-based rare variants analyses revealed five genes associated with iRBD: GBA1 , PLEKHM1 , LRP2 , P2RX1 , and HAP1. Subsequent analysis of these genes in Parkinson’s disease and dementia with Lewy bodies replicated several associations. Together, these findings provide novel insights into the shared genetic architecture underlying iRBD, neurodegenerative disorders, and psychiatric traits, with implications for early identification and mechanistic understanding.
Lack of epistatic interaction of
SNCA
with
APOE
in synucleinopathies
Abstract Two recent studies suggested that the APOE ε4 haplotype was associated with increased α-synuclein pathology in cell and mouse models. Genetic variants in the SNCA region have strong association with Parkinson’s disease (PD), dementia with Lewy bodies (DLB) and idiopathic REM sleep behaviour disorder (iRBD), while APOE is a genetic risk determinant for only DLB. To determine if genetic-level interactions between SNCA and APOE exists that can explain the protein-level association, we investigated the genotypic interaction of APOE and SNCA in cohorts of PD, DLB and iRBD. We analysed genome-wide association study (GWAS) data from 5229 PD patients and 5480 controls, 2610 DLB patients and 1920 controls, and 1055 iRBD patients and 3667 controls. We used logistic regression interaction models across all three cohorts independently between the (i) top GWAS signals of SNCA single nucleotide polymorphisms (SNPs) and APOE haplotypes and (ii) SNP×SNP and three-way SNP interaction across the entire coding region plus 200 kb flanking each gene. No significant interactions were found to be associated with any of the synucleinopathies after correction for multiple testing. Our results do not support a role for genetic interactions between APOE and SNCA across PD, DLB and iRBD. Since the tested genetic variants affect the expression and function of these proteins, it is likely that any interactions between them do not affect the risk of PD, DLB and iRBD.
Abstract FR498: Impact of Switching From High- to Low-Sodium Oxybate on Ambulatory and Office Blood Pressure in Subgroups of People With Narcolepsy From the XYLO Study
Introduction: Excess sodium intake is strongly linked with hypertension and cardiovascular disease (CVD); people with narcolepsy (PwN) have increased CV risk. Hypothesis: Switching from high-sodium oxybate (SXB; Xyrem ® ; 6–9 g for ≥6 wks) to low-sodium oxybate (LXB; Xywav ® ; same regimen) reduces mean 24-hr ambulatory systolic blood pressure (ASBP) after ≈6 wks in PwN, regardless of antihypertensive (anti-HTN) use and site type. Methods: XYLO, an open-label, single-arm study (NCT05869773), assessed PwN aged 18−70 y with office SBPs of 130−155 mmHg. The primary and key secondary endpoints were changes from baseline (BL) to end-of treatment (EOT) in mean 24-hr ASBP and seated resting (“office”) SBP (OSBP), respectively; exploratory endpoints were diastolic BP (DBP) changes. Changes are baseline adjusted. Prespecified subgroup analyses explored BL anti-HTN use and participation site (ie, site-based [at study site] vs decentralized [at-home]). Results: In 43 PwN (mean age, 45 y; female, 65%; anti-HTN, 33%), mean±SD BL OSBP and DBP were 138.0±5.7 and 85.2±6.6 mmHg, respectively. Mean±SD total SXB vs LXB dosages were 8.0±1.1 vs 8.1±1.1 g/night, reflecting 1457±206 vs 118±16 mg sodium (difference: ≈1339 mg); median 24-hr urinary sodium was 4232 mg/d at BL and 2703 mg/d at EOT (median change: 1288 mg/d). Mean change in 24-hr ASBP (least squares mean [95% CI]) was −4.1 (−6.9, −1.4; 1-sided P =0.0019) mmHg (Fig 1) ; mean change in OSBP was −9.2 (−11.9, −6.5; 1-sided P <0.0001). Mean changes in 24-hr ambulatory and office DBP were −2.3 (−4.1, −0.5; 2-sided P =0.0118; nominal) and −3.8 (−6.0, −1.6; 2-sided P =0.0014; nominal) mmHg, respectively. In subgroups, mean change in 24-hr ASBP was −4.6 (−9.6, 0.3) mmHg with BL anti-HTN use and −3.9 (−7.3, −0.5) mmHg without BL anti-HTN use; changes in OSBP were −11.8 (−16.5, −7.1) and −7.9 (−11.1, −4.6) mmHg. Mean change in 24-hr ASBP was −3.6 (−8.0, 0.9) mmHg for site-based and −4.5 (−8.1, −1.0) mmHg for decentralized participation. Corresponding changes in OSBP were −9.0 (−13.3, −4.6; site-based) and −9.3 (−12.8, −5.8; decentralized) mmHg with a downward trend over 6 wks ( Fig 2 ). Treatment-emergent adverse events (all mild/moderate) occurred in 40% of PwN (N=67). Conclusions: Switching from SXB to LXB reduced daily medication-related sodium intake in PwN and was associated with clinically meaningful BP reductions overall and across subgroups, consistent with evidence on dietary and medication-related sodium effects.
Effects of High- Versus Low-Sodium Oxybate on Blood Pressure in Patients With Narcolepsy
BACKGROUND: People with narcolepsy are at increased risk for hypertension and cardiovascular disease; excessive sodium intake is linked to both. METHODS: We studied patients with narcolepsy and office systolic blood pressures (BPs) of 130 to 155 mm Hg taking twice-nightly high-sodium oxybate for ≥6 weeks who switched to low-sodium oxybate at the same dosage. The primary end point was the change from baseline in mean 24-hour ambulatory systolic BP at the end of treatment (≈6 weeks after switching). Secondary and exploratory end points included changes in diastolic BP, office BP, and 24-hour sodium excretion. RESULTS: Patients (n=43) had a mean age of 45 years, were 65% female, 33% on antihypertensives, with baseline mean (SD) office BP of 138.0/85.2 (5.7/6.6). Mean (SD) total high- and low-sodium oxybate dosages of 8.0 (1.1) and 8.1 (1.1) g/night, respectively, represented 1456.5 (206.2) and 117.8 (16.3) mg of sodium. The median 24-hour urinary sodium was 4278 mg/d at baseline and 2703 mg/d at the end of treatment (median change, 1288 mg/d). Mean (SE) 24-hour ambulatory systolic BPs at baseline and study end were 132.3 (1.8) and 128.2 (1.8) mm Hg (least-squares mean change, −4.1 [95% CI, −6.9 to −1.4] mm Hg; 1-sided P =0.0019). BP changes by narcolepsy subtype, sex, body mass index, baseline office BP, and baseline antihypertensive use were consistent with the overall effect size. CONCLUSIONS: People with narcolepsy switching from high- to low-sodium oxybate showed substantially reduced daily medication-related sodium intake and significant 24-hour BP reductions. These results demonstrate the importance of reducing pharmaceutical sodium content in this elevated cardiovascular risk patient population. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT05869773.
Restless Legs Syndrome, Periodic Leg Movements, Hypertension and Cardiovascular Diseases
Restless legs syndrome (RLS) is a frequent sleep-related sensorimotor disorder defined by an urge to move the legs in the evening while resting. Severe RLS symptoms can negatively impact sleep, mood, and quality of life. Periodic leg movements during sleep and wakefulness are found in 60% to 80% of patients with RLS. The pathophysiology of RLS and periodic leg movement is still poorly understood and involves brain iron deficiency, dopamine dysregulation, and genetic predisposition. Over the past decades, several cross-sectional and longitudinal studies have reported an association between RLS, cardiovascular disease, and hypertension although the magnitude, direction, and underlying mechanisms of these associations remain inconclusive. Periodic leg movements during sleep are concomitant with an increase in blood pressure and heart rate, which may affect the physiological nocturnal blood pressure dip and, therefore, lead to an increased incidence of cardiovascular disease. Insomnia and sleep deprivation linked to sensory discomfort could also increase the sympathetic tone and contribute to an increase in cardiovascular risk. Comorbidities and associated sleep disorders may also synergically increase cardiovascular risk. This narrative review details the current knowledge of RLS, a still underdiagnosed and poorly recognized disorder, and examines the epidemiological relationship between RLS, cardiovascular disease and hypertension, potential mechanisms underlying this association, and strategies to reduce the risk of cardiovascular disease in patients with moderate-to-severe RLS. Greater multidisciplinary collaborations between cardiologists and sleep specialists are needed to better identify, understand, and manage patients with sleep disorders, including those with RLS.
Sleep Disruption and Atrial Fibrillation: Evidence, Mechanisms and Clinical Implications
Atrial fibrillation (AF) is the most prevalent sustained cardiac arrhythmia, with its incidence rising due to aging populations, obesity, and advancements in diagnostic modalities. The interplay between sleep disorders and AF is increasingly recognized, with obstructive sleep apnea (OSA) serving as a well-established risk factor. However, emerging evidence implicates additional sleep disturbances—including central sleep apnea, insomnia, and restless legs syndrome—in AF pathogenesis and progression. Despite compelling observational data, interventional studies evaluating the impact of sleep disorder treatment on AF outcomes have yielded mixed results. Although continuous positive airway pressure therapy in patients with OSA mitigates AF recurrence, randomized controlled trials have yet to confirm a definitive causal benefit. This review synthesizes epidemiological, mechanistic, and interventional data linking sleep disorders to AF.
Predictors of Neurodegeneration in Idiopathic REM sleep behavior disorder: a multicenter cohort study (CCI.003)
ObjectiveThis study assessed the relationship between speech and language impairment and outcome in a multicenter cohort of isolated/idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD).MethodsPatients with iRBD from 7 centers speaking Czech, English, German, French, and Italian languages underwent a detailed speech assessment at baseline. Story‐tale narratives were transcribed and linguistically annotated using fully automated methods based on automatic speech recognition and natural language processing algorithms, leading to the 3 distinctive linguistic and 2 acoustic patterns of language deterioration and associated composite indexes of their overall severity. Patients were then prospectively followed and received assessments for parkinsonism or dementia during follow‐up. The Cox proportional hazard was performed to evaluate the predictive value of language patterns for phenoconversion over a follow‐up period of 5 years.ResultsOf 180 patients free of parkinsonism or dementia, 156 provided follow‐up information. After a mean follow‐up of 2.7 years, 42 (26.9%) patients developed neurodegenerative disease. Patients with higher severity of linguistic abnormalities (hazard ratio [HR = 2.35]) and acoustic abnormalities (HR = 1.92) were more likely to develop a defined neurodegenerative disease, with converters having lower content richness (HR = 1.74), slower articulation rate (HR = 1.58), and prolonged pauses (HR = 1.46). Dementia‐first (n = 16) and parkinsonism‐first with mild cognitive impairment (n = 9) converters had higher severity of linguistic abnormalities than parkinsonism‐first with normal cognition converters (n = 17).InterpretationAutomated language analysis might provide a predictor of phenoconversion from iRBD into synucleinopathy subtypes with cognitive impairment, and thus can be used to stratify patients for neuroprotective trials. ANN NEUROL 2024;95:530–543