Author(s): Flemons WW, Reimer MA
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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.
This article was published in Am J Respir Crit Care Med
and referenced in Journal of Sleep Disorders & Therapy