0961 Association of Newly Diagnosed Idiopathic Hypersomnia and Risk of Major Adverse Cardiovascular Events

Abstract Introduction Evidence suggests that hypersomnolence disorders, including narcolepsy, are associated with increased risk of major adverse cardiovascular events (MACE). Although most work has focused on narcolepsy, idiopathic hypersomnolence (IH) may also confer elevated cardiovascular risk. However, the long-term relationship between IH and MACE remains poorly characterized. We examined whether a new IH diagnosis is associated with increased incidence of MACE in a large, nationally representative claims cohort. Methods We constructed a retrospective cohort using MarketScan® data (2005–2022). IH patients were included at the index date of IH diagnosis and were required to have a confirmatory sleep study (multiple sleep latency test or polysomnography) within 60 days before the index date. A comparison cohort without IH was selected at a 1:500 ratio, matched on age, sex, and index date. We excluded individuals with narcolepsy, prior MACE (myocardial infarction, stroke, heart failure, unstable angina, or cardiovascular death), or subclinical cardiometabolic disease (type 2 diabetes, hypertension, hyperlipidemia, dyslipidemia, or NAFLD) within 1 year before index date, and those without ≥1 year of continuous enrollment prior to index. Baseline characteristics and crude MACE incidence rates were summarized for both cohorts. Results We identified 5,472 individuals with newly diagnosed IH and 1,206,603 matched comparison patients (67.0% vs 69.7% female, ≤25 years old: 26.1% vs. 32.4%; 26-45 years old: 49.3% vs. 49.8%; 46-65 years old: 24.6% vs. 17.8%). Sleep apnea (34.0% vs 2.2%), insomnia (4.7% vs. 1.1%), PLMD (3.0% vs. 0.1%), RLS (2.4% vs. 0.2%) was different between both groups. Among IH patients, the unadjusted incidence rate of MACE was 0.49 per 100 person-years (mean follow-up: 2.78 years), compared with 0.38 per 100 person-years in the comparison cohort (mean follow-up: 2.88 years). Conclusion Newly diagnosed IH was associated with a higher crude incidence of MACE compared with a large matched cohort without IH. To further reduce confounding, propensity score matching (1:3) will be conducted to balance baseline risk factors including sleep comorbidities, and adjusted hazard ratios will be estimated. These findings underscore the need for heightened cardiovascular risk assessment and early prevention in patients with IH. Support (if any) Sleep Research Society Foundation (Grant #: 25-FRA-001).