title: Different fates of excessive daytime sleepiness: survival analysis for remission.
abstract: BACKGROUND
  Excessive daytime sleepiness (EDS) is a symptom frequently presented in sleep clinics. Only a paucity of data has addressed clinical courses of sleep disorders with EDS. Therefore, we sought to compare clinical outcomes of patients presenting EDS.
  
  
  METHODS
  A retrospective observational study was performed in the setting of sleep laboratory and outpatient department in a university hospital. One hundred and eight patients who presented EDS underwent polysomnography and multiple sleep latency test. Each patient was diagnosed as one of the following four categories: (1) narcolepsy with cataplexy (N + C; n = 29); (2) narcolepsy without cataplexy (N - C; n = 22); (3) idiopathic hypersomnia (IH; n = 24); and (4) subjective hypersomnolence (SH; n = 33) with mean sleep latency >8 min. Remission of EDS and treatment response were determined based on clinical evaluation. Kaplan-Meier survival analysis was performed.
  
  
  RESULTS
  Remission rates were significantly different (P < 0.001, overall log-rank test) among four groups except those between N - C and IH (P = 0.489). While N + C showed no remission, predicted remission rates of N - C and IH group were 44.6% at 5 years and 32.5% at 5.5 years after diagnosis. The predicted remission rate of SH group was 71.7% at 3 years after diagnosis.
  
  
  CONCLUSIONS
  The similarity of clinical courses between N - C and IH suggests that N - C may be more related to IH compared to N + C. Considering different clinical courses among EDS patients, thorough evaluation of EDS should be warranted before starting treatment.
authors.affiliation: Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, Korea.|Department of Psychiatry, Kyung Hee University Hospital at Gangdong, Seoul, Korea.
authors.forename: T
authors.initials: T
authors.lastname: Kim
authors.affiliation: Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, Korea.
authors.forename: C S
authors.initials: CS
authors.lastname: Lee
authors.affiliation: Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, Korea.|Department of Psychiatry, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: I Y
authors.initials: IY
authors.lastname: Yoon
mesh_terms: D000328:Adult; D000368:Aged; D002385:Cataplexy; D006970:Disorders of Excessive Somnolence; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009290:Narcolepsy; D017286:Polysomnography; D012074:Remission Induction; D012189:Retrospective Studies; D012890:Sleep / Q000502:physiology*; D016019:Survival Analysis; D055815:Young Adult
keywords: excessive daytime sleepiness; idiopathic hypersomnia; narcolepsy; remission