Health Preference Measures in Patients with Obstructive Sleep Apnea Syndrome Undergoing Continuous Positive Airway Pressure Therapy: Data from a Randomized Trial

Abstract

Background: In patients with obstructive sleep apnea syndrome (OSAS), the preference-based, health-related quality of life in terms of utility has not been extensively studied.

Objective: To address this point, we compared the performance of different instruments assessing utility in patients with OSAS undergoing continuous positive airway pressure (CPAP) therapy.

Materials and methods: Data of 208 patients with OSAS (28 women, mean ± SE age 54.4 ± 0.7 years, apnea-hypopnea index (AHI) 51.9 ± 1.8/h, Epworth sleepiness score 13.4 ± 0.2) participating in a randomized trial of different CPAP modalities over 2 years were analyzed. Evaluations included sleep studies, Epworth sleepiness scale, and several utility instruments that measure subjective health preference on a scale ranging from 1 (most preferred and perfect health) to 0 (least preferred and very poor health).

Results: After 2 years of CPAP therapy, the mean ± SE AHI was 6.7 ± 1.5/h and Epworth score 7.9 ± 0.4, both p < 0.001 versus baseline. Baseline utilities and changes (95% confidence interval) after 2 years of CPAP therapy were EuroQol 5-dimensions 0.79 ± 0.01, 0.02 (0.00-0.05, p = 0.064); short-form 6-dimension medical outcome questionnaire 0.72 ± 0.01, 0.06 (0.04-0.08, p < 0.001); Euro-thermometer visual analog scale 0.70 ± 0.01, 0.09 (0.07-0.12, p < 0.001); time trade-off 0.82 ± 0.01, 0.03 (0.01-0.06, p = 0.002); and standard gamble 0.82 ± 0.01, -0.01 (-0.03 to 0.02, p = 0.712).

Conclusion: The short-form 6-dimensions questionnaire, the Euro-thermometer, and the time trade-off instruments reflected the major clinical improvements in OSAS, while the EuroQoL 5-dimensions and standard gamble tests were not sensitive to CPAP effects. These results indicate that the evaluation of utility of a treatment for OSAS depends critically on the instrument used, which is important from an individual and societal perspective.

Keywords: Cost-utility analysis; Health-related quality of life; Noninvasive ventilation; Sleep apnea.

Fig. 1

Participant flow.

Fig. 2

Effects of CPAP therapy on mean (SD) main outcomes in patients with the over the course of 2 years. Results are not statistically different for patients randomized to autoCPAP and fCPAP, and main effects were achieved within the first 3 months of treatment. *p < 0.05 for changes of autoCPAP and fCPAP at 3 months versus baseline and #p < 0.05 for changes of fCPAP at 24 versus 3 months. CPAP, continuous positive airway pressure; fCPAP, fixed CPAP; auotCPAP, autoadjusted CPAP; OSAS, obstructive sleep apnea syndrome.

Fig. 3

Plot of mean effect sizes with 95% CIs of CPAP therapy compared to pretreatment baseline. Each panel shows results after 3, 12, and 24 months of CPAP therapy. AHI, apnea-hypopnea index; ESS, Epworth sleepiness scale; SF-36_vt, short-form medical outcome questionnaire vitality score; EQ-5D, EuroQol 5-dimension utility index; SF-6D, short-form 6-dimension utility index; VAS, Euro-thermometer visual analog scale utility index; TTO, time trade-off utility index; SG, standard gamble utility index; CPAP, continuous positive airway pressure; AHI, apnea-hypopnea index; CI, confidence interval.