0629 The Lehigh Valley Health Network Narcolepsy Cohort: Clinical and Polysomnographic Analysis of 303 Cases

Abstract Introduction Narcolepsy has been associated with several psychiatric, cardiovascular and metabolic disorders. This study aimed to analyze the clinical and polysomnographic characteristics of narcolepsy patients within the Lehigh Valley Health Network (LVHN). Methods We performed a chart-review of all narcolepsy cases seen between 2000 and 2022. Bivariate analysis highlighted differences between narcolepsy-type I (NT1) and narcolepsy-type II (NT2). Results Among 3.3 million patients, 303 (0.0001%, 9 per 100,000) were diagnosed with narcolepsy (51 with NT1, 252 with NT2), based on ICDS-3 diagnostic criteria. Age at symptom onset was 20.5±6.8 years. Diagnostic delay was 4.1 (2.0-8.9) years. Average Epworth Sleepiness Scale (ESS) was 16.9±2.9. Concomitant symptoms were refreshing naps 226(74.6%), hypnagogic hallucinations 87(28.7%), disrupted sleep 86(28.4%), sleep paralysis 77(25.4%). Compared to NT2, NT1 patients had earlier age at diagnosis (24.3±8.0 versus 27.6±9.1, p=0.02), shorter diagnostic gap (3.0 vs 4.6 years, p=0.001), more frequent sleep paralysis 27(52.9%) vs 50(19.8%) p 0.0001, hygnagogic hallucinations 22(43.1%) vs 65(25.8%), p=0.01, higher ESS (17.6±3.3 versus 16.7±2.8, p=0.04). Comorbid sleep disorders were breathing disorders (17.5%), insomnia (15.5%), restless legs syndrome (3.6%), periodic limb movements (2.3%), and REM parasomnias (1.3%). Migraine was the most common neurological disorder (29.7%). Frequent mood disorders included depression (34.7%) and anxiety (32.3%). Depression was more common in NT2 11 (21.6%) vs 94 (37.3%) p=0.03. Hypertension, diabetes, and obesity prevalence were not different between the two groups (overall 24.1%, 8.3%, 12.5% respectively). The most common treatments were modafinil (66.3%), methylphenidate (31.3%), armodafinil (28.1%), dextroamphetamine (28.8%), sodium oxybate (8.7%), pitolisant (4.5%), solriamfetol (5.2%). Review of overnight-polysomnography showed an average sleep efficiency of 93%, sleep latency of 12.3 minutes, REM latency of 98.8 minutes, with no differences between NT1 and NT2. Multiple sleep latency test showed an average sleep latency of 3.7 (2.4-5.0) minutes, and more SOREMPs in NT1 (≥3 in 28 (58.3%) vs 64 (27.1%), p 0.0001). Conclusion This study is one of the largest monocentric studies to date of patients with narcolepsy and confirms the frequent comorbidity of narcolepsy with many other disorders. Specific clinical characteristics and comorbidities may help differentiate NT1 from NT2. Further analysis on this dataset is in progress and will be presented. Support (if any)