title: Psychometric performance and responsiveness of the functional outcomes of sleep questionnaire and sleep apnea quality of life instrument in a randomized trial: the HomePAP study.
abstract: OBJECTIVE
  Measures of health-related quality of life (HRQL) specific for sleep disorders have had limited psychometric evaluation in the context of randomized controlled trials (RCTs). We investigated the psychometric properties of the Functional Outcomes of Sleep Questionnaire (FOSQ) and Sleep Apnea Quality of Life Instrument (SAQLI). We evaluated the FOSQ and SAQLI construct and criterion validity, determined a minimally important difference, and assessed for associations of responsiveness to baseline subject characteristics and continuous positive airway pressure (CPAP) adherence in a RCT population.
  
  
  METHODS
  Secondary analysis of data collected in a multisite RCT of home versus laboratory-based diagnosis and treatment of obstructive sleep apnea (HomePAP trial).
  
  
  METHODS
  Individuals enrolled in the HomePAP trial (n = 335).
  
  
  METHODS
  N/A.
  
  
  RESULTS
  The FOSQ and SAQLI subscores demonstrated high reliability and criterion validity, correlating with Medical Outcomes Study 36-Item Short Form Survey domains. Correlations were weaker with the Epworth Sleepiness Scale (ESS). Both the FOSQ and SAQLI scores improved after 3 mo with CPAP therapy. Averaging 4 h or more of CPAP use was associated with an increase in the FOSQ beyond the minimally important difference. Baseline depressive symptoms and sleepiness predicted FOSQ and SAQLI responsiveness; demographic, objective obstructive sleep apnea (OSA) severity and sleep habits were not predictive in linear regression.
  
  
  CONCLUSIONS
  The FOSQ and SAQLI are responsive to CPAP intervention, with the FOSQ being more sensitive to differences in CPAP adherence than the SAQLI. These instruments provide unique information about health outcomes beyond that provided by changes in physiological measures of OSA severity (apnea-hypopnea index).
  
  
  BACKGROUND
  Portable Monitoring for Diagnosis and Management of Sleep Apnea (HomePAP) URL: http://clinicaltrials.gov/show/NCT00642486. NIH clinical trials registry number: NCT00642486.
authors.affiliation: UW Medicine Sleep Center, Division of Pulmonary Critical Care, University of Washington, Seattle, WA.
authors.forename: Martha E
authors.initials: ME
authors.lastname: Billings
authors.affiliation: Case Western Reserve University, School of Medicine, Cleveland, OH: Rainbow Babies and Children's Hospital, University Hospitals, Case Medical Center, Cleveland, OH.
authors.forename: Carol L
authors.initials: CL
authors.lastname: Rosen
authors.affiliation: Case Western Reserve University, School of Medicine, Cleveland, OH: Center for Sleep Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, MetroHealth Medical Center, Cleveland, OH.
authors.forename: Dennis
authors.initials: D
authors.lastname: Auckley
authors.affiliation: Department of Psychiatry, University of Wisconsin, Madison, WI.
authors.forename: Ruth
authors.initials: R
authors.lastname: Benca
authors.affiliation: Case Western Reserve University, School of Medicine, Cleveland, OH: Cleveland Clinic, Cleveland, OH.
authors.forename: Nancy
authors.initials: N
authors.lastname: Foldvary-Schaefer
authors.affiliation: Hennepin County Medical Center, University of Minnesota, Minneapolis, MN.
authors.forename: Conrad
authors.initials: C
authors.lastname: Iber
authors.affiliation: Northwestern University, Feinberg School of Medicine, Chicago, IL.
authors.forename: Phyllis C
authors.initials: PC
authors.lastname: Zee
authors.affiliation: Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Susan
authors.initials: S
authors.lastname: Redline
authors.affiliation: UW Medicine Sleep Center, Division of Pulmonary Critical Care, University of Washington, Seattle, WA.
authors.forename: Vishesh K
authors.initials: VK
authors.lastname: Kapur
mesh_terms: D045422:Continuous Positive Airway Pressure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D011594:Psychometrics; D011788:Quality of Life; D015203:Reproducibility of Results; D012890:Sleep / Q000502:physiology*; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology* / Q000523:psychology* / Q000628:therapy; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
keywords: health-related quality of life; psychometrics; sleep apnea