Effect of continuous positive airway pressure on the risk of road accidents in sleep apnea patients.

Background: Continuous positive airway pressure (CPAP) reduces daytime somnolence in the obstructive sleep apnea syndrome (OSAS) and may contribute to a reduction in the risk of motor vehicle accidents. Objective: To evaluate the effects of CPAP on automobile collisions in patients with OSAS. Methods: We compared the number of motor vehicle accidents in 80 patients with OSAS and 80 healthy subjects during the 2 years before and the 2 years after study entry, at which CPAP treatment was initiated. Results: Patients with OSAS had a 2.6 times higher risk of suffering an automobile collision compared to controls (rate ratio, RR = 2.57; 95% confidence interval, CI = 1.30-5.05). After 2 years of CPAP treatment, the rate of collisions was reduced more than half in patients with OSAS (RR = 0.41; 95% CI = 0.21-0.79), but this occurred also in controls (RR = 0.49; 95% CI = 0.17-1.40). The magnitude of this fall between groups was not different (p for interaction = 0.68), even after adjusting for body mass index, alcohol intake and Epworth scale. Conclusions: Patients with OSAS have an increased risk of suffering a traffic collision. This risk was significantly reduced after their inclusion in the study. Yet, as this reduction also occurred in the control group, this effect may not be due to CPAP therapy. Copyright (C) 2007 S. Karger AG, Basel.