Screening for obstructive sleep apnea in stroke patients - A cost-effectiveness analysis

Background and Purpose - Obstructive sleep apnea (OSA) is common after acute ischemic stroke and predicts poor stroke recovery, but whether screening for OSA and treatment by continuous positive airway pressure ( CPAP) improves neurological outcome is unknown. We used a cost-effectiveness model to estimate the magnitude of benefit that would be necessary to make polysomnography (PSG) and OSA treatment cost-effective in stroke patients. Methods - A decision tree modeled 2 alternative strategies: PSG followed by 3 months of CPAP for those found to have OSA versus no screening. The primary outcome was the utility gained through OSA screening and treatment in relation to 2 common willingness-to-pay thresholds of $50 000 and $100 000 per quality-adjusted life year ( QALY). Results - Screening resulted in an incremental cost-effectiveness ratio of $49 421 per QALY. Screening is cost-effective as long as the treatment of stroke patients with OSA by CPAP improves patient utilities by > 0.2 for a willingness-to-pay of $50 000 per QALY and 0.1 for a willingness-to-pay of $100 000 per QALY. Conclusions - A clinical trial assessing the effectiveness of CPAP in improving stroke outcome is warranted from a cost-effectiveness standpoint.