title: Obstructive Sleep Apnea and Quality of Life: Comparison of the SAQLI, FOSQ, and SF-36 Questionnaires.
abstract: BACKGROUND
  The impact of sleep on quality of life (QoL) has been well documented; however, there is a great need for reliable QoL measures for persons with obstructive sleep apnea (OSA). We compared the QoL scores between the 36-Item Short Form of the Medical Outcomes Survey (SF-36), Calgary Sleep Apnea Quality of Life Index (SAQLI), and Functional Outcomes Sleep Questionnaire (FOSQ) in persons with OSA.
  
  
  METHODS
  A total of 884 participants from the Sleep Heart Health Study second examination, who completed the SF-36, FOSQ, and SAQLI, and in-home polysomnograms, were included. The apnea hypopnea index (AHI) at 4% desaturation was categorized as no OSA (<5 /hour), mild to moderate OSA (5-30 /hour) and severe OSA (>30 /hour). QoL scores for each questionnaire were determined and compared by OSA severity category and by gender.
  
  
  RESULTS
  Participants were 47.6% male, 49.2% (n=435) had no OSA, 43.2% (n=382) had mild to moderate OSA, and 7.6% (n=67) had severe OSA. Participants with severe OSA were significantly older (mean age = 63.7 years, p <.0001), had higher BMI (mean = 34.3 kg/m2, p <.0001) and had lower SF-36 Physical Component scores (PCS) (45.1) than participants with no OSA (48.5) or those with mild to moderate OSA (46.5, p= .006). When analyzed according to gender, no significant differences were found in males for QoL by OSA severity categories. However, females with severe OSA had significantly lower mean scores for the SAQLI (5.4, p= .006), FOSQ (10.9, p= .02), and SF-36 PCS (37.7, p<.0001) compared to females with no OSA (6.0, 11.5, 44.6) and those with mild to moderate OSA (5.9, 11.4, 48, respectively). Females with severe OSA also had significantly higher mean BMI (41.8 kg/m2,) than females with no OSA (26.5 kg/m2) or females with mild to moderate OSA (30.6 kg/m2, p<.0001). The SF-36 PCS and Mental Component Scores (MCS) were correlated with the FOSQ and SAQLI (r=.37 PCS vs FOSQ; r=.31 MCS vs FOSQ; r=.42 PCS vs SAQLI; r=.52 MCS vs SAQLI; and r=.66 FOSQ vs SAQLI, p<.001 for all correlations). Linear regression analyses, adjusting for potential confounders, indicated that the impact of OSA severity on QoL is largely explained by the presence of daytime sleepiness.
  
  
  CONCLUSIONS
  The impact of OSA on QoL differs between genders with a larger effect on females and is largely explained by the presence of daytime sleepiness. Correlations among QoL instruments are not high and various instruments may assess different aspects of QoL.
authors.affiliation: University of Arizona College of Nursing, Tucson, AZ.
authors.forename: Graciela E
authors.initials: GE
authors.lastname: Silva
authors.affiliation: Arizona Respiratory Center, University of Arizona, Tucson, AZ.
authors.forename: James L
authors.initials: JL
authors.lastname: Goodwin
authors.affiliation: College of Nursing & Health Innovation, Arizona State University, Phoenix, AZ.
authors.forename: Kimberly D
authors.initials: KD
authors.lastname: Vana
authors.affiliation: Arizona Respiratory Center, University of Arizona, Tucson, AZ; College of Medicine, University of Arizona, Tucson, AZ; Division of Sleep Medicine, Harvard Medical School, Boston, MA; Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Boston, MA.
authors.forename: Stuart F
authors.initials: SF
authors.lastname: Quan