0658 FREQUENCY AND PREDICTORS OF SYSTEMIC EXERTION INTOLERANCE DISEASE/CHRONIC FATIGUE SYNDROME AMONG SLEEP CENTER PATIENTS REFERRED FOR HYPERSOMNOLENCE EVALUATION

Abstract

Introduction: Symptoms of central disorders of hypersomnolence (CDH) extend beyond excessive daytime sleepiness (EDS) to include non-restorative sleep, fatigue and cognitive dysfunction. Thus, they share much in common with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), recently renamed systemic exertion intolerance disease (SEID), whose additional discriminating features include post-exertional malaise and orthostatic intolerance. Clarifying the distinction and overlap between these disorders will help guide patient management. Methods: Patients evaluated for hypersomnolence completed a questionnaire battery about EDS and fatigue; questionnaires and clinical records were used for SEID assessment. PSG/MSLT, CSF hypocretin, and cataplexy status were additionally used to assign ICSD-3 diagnoses of CDH or sleep apnea. Patients reporting problematic hypersomnolence but not meeting any ICSD-3 criteria (i.e., with MSL > 8 min) were labelled subjective EDS (sEDS). Results: Final sample was 205 patients, with mean age 35.6 years (+/- 14.9; 63% women) and diagnoses of idiopathic hypersomnia (n=68), narcolepsy type 1 (n=6), narcolepsy type 2 (n=25), persistent sleepiness after OSA treatment (n=25), insufficient sleep (n=41), psychiatric hypersomnolence (n=7), and sEDS (n=33). Nineteen percent met SEID criteria, and frequency of SEID was not different across ICSD-3 diagnoses (p=0.33). MSLT mean sleep latency was not different between those with and without SEID (6.58 vs 6.63, p=0.95). Patients with SEID were more likely than those without to have failed standard hypersomnolence treatments (88.6% vs 67.8%, p=0.02), but had similar response rates to clarithromycin (37.5% vs 42.9%, p=0.59) and flumazenil (64.0% vs 59.2%, p=0.67). SEID patients were no different from those without SEID by gender, age, chronotype, sleep duration, Epworth, depressive symptoms, family history, or PSG/ MSLT parameters. Conclusion: Nearly one-in-five patients evaluated for hypersomnolence meet SEID criteria, but this diagnosis is independent of ICSD-3 diagnoses and PSG/MSLT findings. Patients with comorbid SEID may be more refractory to standard hypersomnolence treatments, but appear no less likely to benefit from GABA-A antagonists