In non-sleepy patients with obstructive sleep apnea (OSA), treatment with continuous positive airway pressure (CPAP) can reduce the incidence of cardiovascular events and hypertension, according to researchers from Spain.

The research was presented at the ATS 2010 International Conference in New Orleans.

"Our study showed that even in non-sleepy OSA patients, CPAP usage could reduce the incidence of cardiovascular events and hypertension," said Ferran Barbe Illa, M.D., of the Hospital Arnau de Vilanova in Lleida, Spain. "We found a statistically significant decrease for those subjects that use CPAP for at least four hours a night."

OSA is known to be associated with cardiovascular disease and stroke. CPAP is the current standard of treatment for patients with symptomatic OSA. CPAP improves daytime sleepiness, and quality of life in patients with OSA. Although daytime sleepiness is one of the main symptoms of sleep apnea, not all patients with OSA complain of it. Therefore, CPAP usage for OSA subjects without sleepiness is unclear.

To determine whether CPAP would reduce cardiovascular risks in OSA patients without daytime sleepiness, Dr. Barbe Illa and colleagues recruited 724 patients with moderate to severe sleep apnea (AHI>20) and Epworth sleep scores of less than 10, indicating minimal daytime sleepiness despite significant OSA. The patients were randomized to be treated with CPAP or conservative treatment (in which their doctors provided advice on weight control and sleep) and followed for four years.

At the end of four years, Dr. Barbe Illa and colleagues found that the risk of a having cardiovascular event-such as stroke, angina pectoris, cardiac arrhythmia or peripheral ischemia-or developing hypertension among patients who used CPAP for at least four hours a night was reduced by 25 percent compared to those who did not use CPAP. Among those who had baseline hypertension and used CPAP for four or more hours a night, the risk of a cardiovascular event declined to nearly half of those who did not use CPAP.

"The positive effects of CPAP on cardiovascular incidence are not observed across the entire range of patients with OSA," said Dr. Barbe Illa. "This study aimed to determine the effects of CPAP treatment on OSA patients to improve clinical guidelines for OSA treatment. It is plausible that long-term and adequate treatment with CPAP may decrease the development of cardiovascular events in non-sleepy patients and, therefore, also in these patients is recommended to indicate the treatment with CPAP, despite the lack of daytime symptoms."

More research is necessary for a better understanding of OSA physiopathology and to determine the CPAP treatment effects are evident in the entire range of OSA patients.

"This and future studies will contribute to better understanding of CPAP treatment effects in non-sleepy patients, and consequently to adapt clinical guidelines of OSA treatment. In fact, it is the first randomized study that shows a positive effect of CPAP on cardiovascular diseases in patients with OSA," said Dr. Barbe Illa.