title: Nightly variability of sleep-disordered breathing measured over 3 nights.
abstract: OBJECTIVE
  To examine the nightly variability of sleep-disordered breathing (SDB) as measured by the apnea-hypopnea index (AHI).
  
  
  METHODS
  Retrospective comparison of 3 sequential nights of testing performed in the home in 1091 patients who were referred for diagnostic testing of SDB.
  
  
  RESULTS
  The Pearson and Intraclass correlation coefficients ranged between 0.88 and 0.90 for each pair of nights. Based on night 1, approximately 90% of patients were classified consistently with "AHI-high" (the highest AHI measured across the 3 nights) using an AHI threshold of 5. However, 10% were misclassified on night 1 relative to the highest AHI level.
  
  
  CONCLUSIONS
  These findings suggest that (1) 1 night of diagnostic testing for SDB is not sufficient to diagnosis SDB in approximately 1 of every 10 cases, and (2) there is little, if any, significant nightly change in SDB in the home environment.
  
  
  METHODS
  D.
authors.affiliation: Health Services Research & Development Service, Veterans Affairs San Diego Healthcare System, California 92161, USA. cstepnowsky@ucsd.edu
authors.forename: Carl J
authors.initials: CJ
authors.lastname: Stepnowsky
authors.forename: William C
authors.initials: WC
authors.lastname: Orr
authors.forename: Terence M
authors.initials: TM
authors.lastname: Davidson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory; D017286:Polysomnography; D012189:Retrospective Studies; D012891:Sleep Apnea Syndromes / Q000175:diagnosis / Q000503:physiopathology*; D013997:Time Factors