Stroke and other cardiovascular events in patients with obstructive sleep apnea and the effect of continuous positive airway pressure

Obstructive sleep apnea (OSA) is a known-risk factor for cardiovascular diseases. There are indications that treatment with continuous positive airway pressure (CPAP) reduces the risk of new cardiovascular events. In this study, we analyzed the incidence of cardiovascular events in patients with OSA and compared for the impact of CPAP therapy. All polysomnographies performed in 2009 and 2010 were selected with an AHI >= 5 and patients older than 18 years. These 1110 patients were approached with a questionnaire about cardiovascular events and CPAP treatment. Finally, 554 patients were included in analyses. CPAP treatment was based on compliance (level 1 treatment) and extended with residual respiratory events (level 2 treatment). OSA was set as AHI >= 5 and classified in mild (AHI 5-15), moderate (AHI 15-30) and severe (AHI >= 30) OSA. 50 cardiovascular events occurred in 44 patients during follow-up (mean follow-up time 5.9 years) in 554 patients. The events were significantly higher in patients with increasing classification of OSA-severity (p = 0.016). A first-ever cardiovascular event did not differ significantly between mild, moderate and severe OSA. Untreated CPAP patients had significantly more cardiovascular events as compared to treated patients with a hazard ratio of 2.66 partially adjusted for age, AHI and smoking. There was no significant contribution of other cardiovascular risk factors. Patients with OSA with an indication for CPAP treatment have more cardiovascular events when untreated compared to treated patients. This indicates that treatment of OSA by CPAP can reduce the risk for cardiovascular events.