Quality-adjusted life-years gain and health status in patients with OSAS after one year of continuous positive airway pressure use

Abstract

Study Objectives: To estimate the health utility score and quality-adjusted life-years (QALY) index of obstructive sleep apnea syndrome (OSAS) in patients over 1 y of continuous positive airway pressure (CPAP) treatment. Design: Longitudinal interventional study. Setting: The study was carried out in Sao Paulo Sleep Institute, Brazil. Patients and participants: Ninety-five patients with OSAS and with apnea-hypopnea index (AHI) > 20 of either sex, body mass index < 40 kg/m2, and no previous contact with CPAP were included. Interventions: The participants underwent baseline and titration polysomnographies, clinical evaluation, and ambulatory blood pressure (BP) measurement, completed Short-Form 6 Dimension Health Survey (SF-6D) and Epworth Sleepiness Scale (ESS) questionnaires, and implementation of CPAP. The patients were followed for 1 y. Measurements and Results: The mean AHI and age were 57.6 ± 29.2 events/h and 53.3 ± 9.3 y, respectively. One year of CPAP treatment increased the health utility score from 0.611 ± 0.112 to 0.710 ± 0.121 (P < 0.01). Therefore, CPAP resulted in a mean gain of 0.092 QALY/patient. The improvements in utility scores were associated with decreases in the ESS after 1 mo, in systolic BP after 1 y, and in diastolic BP at 6 mo. BP normalization group (≤ 130/85 mmHg) showed higher QALY than that of the non-normalization group (0.10 ± 0.09 versus 0.05 ± 0.10; P = 0.03). One-year ESS score (P = 0.03), diastolic BP reduction P = 0.01) and baseline utility scores (P < 0.01) were significantly associated with QALY gain. Conclusion: This study showed a significant quality-adjusted life-years (QALY)/patient gain after 1 y of regular CPAP use. In addition, blood pressure normalization was associated with higher QALY gain. Thus, utility studies can provide more complete analyses of the total benefits of CPAP treatment in patients with obstructive sleep apnea syndrome and should be encouraged.