Development of a Sleep Apnea–Specific Health State Utility Algorithm

Abstract

With the increasing emphasis on economic evaluations, there is a need for additional methods of measuring patient utility in the obstructive sleep apnea population. To develop and validate a utility scoring algorithm for a sleep apnea-specific quality-of-life instrument. Development and validation were conducted at 2 tertiary referral sleep centers and associated sleep clinics and included patients with newly diagnosed obstructive sleep apnea from a randomized clinical trial and an associated observational cohort study. Baseline participants were randomly divided into a model development group (60%) and a cross-validation group (40%). Utility scoring of the Symptoms of Nocturnal Obstruction and Related Events (SNORE-25) was mapped from the SF-6D utility index through multiple linear regression in the development sample using the Akaike information criterion to determine the best model. A total of 500 participants (development, n = 300; validation, n = 200) were enrolled; the analyzed sample of 500 participants included 295 men (59%), and the mean (SD) age was 48.6 (12.8) years, with a range of 18 to 90 years. The mean (SD) SF-6D utility among participants with untreated sleep apnea was 0.61 (0.08; range, 0.40-0.85) with similar utility across sleep apnea severity groups. The best-fit model (the SNORE Utility Index) was the natural log conversion of the instrument subscales (r2 = 0.32 in the development sample). The SNORE Utility Index retained this association within the validation sample (r2 = 0.33). The SNORE Utility Index provides a validated, disease-specific, preference-weighted utility instrument that can be used in future studies of patients with obstructive sleep apnea.