title: Measurement properties of the calgary sleep apnea quality of life index.
abstract: Sleep apnea patients were studied three times prior to and 4 wk after a trial of nasal continuous positive airway pressure to determine the measurement properties of the Calgary Sleep Apnea Quality of Life Index (SAQLI), a disease-specific quality of life questionnaire. All patients completed the Medical Outcome Survey Short Form (SF-36), the Ferrans and Powers Quality of Life Index, and a global assessment of quality of life before and after treatment. The SAQLI was found to have a very high responsiveness index of 1.9 and an effect size of 1.1, which was much greater than the domains of the SF-36 and the FPQLI. There were statistically significant longitudinal correlations (range: 0.24 to 0.54) between the SAQLI and seven of the SF-36 domains in a pattern that was predicted beforehand and which demonstrated the validity of the SAQLI as an evaluative instrument. The SAQLI also had a range of correlations at baseline with the SF-36 (range: 0.36 to 0.71), the Epworth Sleepiness Scale (-0.26), and the FPQLI (0.29 to 0.66), and with a global rating of quality of life (0.61). The SAQLI had a high reliability coefficient of 0.92 on testing and retesting at 2 wk. We conclude that the SAQLI has excellent measurement properties for an evaluative instrument, and beginning evidence of validity as a discriminative index. It measures components of quality of life that are important to sleep apnea patients, and will be an important outcome measure in clinical trials.
authors.affiliation: Faculties of Medicine and Nursing, University of Calgary, Calgary, Alberta, Canada. flemons@ucalgary.ca
authors.forename: W Ward
authors.initials: WW
authors.lastname: Flemons
authors.forename: Marlene A
authors.initials: MA
authors.lastname: Reimer
mesh_terms: D000328:Adult; D016002:Discriminant Analysis; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D017286:Polysomnography; D011175:Positive-Pressure Respiration; D011788:Quality of Life; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D012891:Sleep Apnea Syndromes / Q000503:physiopathology / Q000628:therapy*; D011795:Surveys and Questionnaires