particularly for patients with moderate to severe OSA and those who are more adherent to CPAP therapy, a new study suggests.
“Most clinical trials on the effect of CPAP on CV diseases to date have focused on secondary CV prevention. This study contributes another piece of evidence about the role of CPAP therapy to prevent CV diseases,” said Diego R. Mazzotti, PhD, an assistant professor at the University of Kansas Medical Center, Kansas City.
“Our study, while observational, suggests that clinical trials focused on understanding how to sustain long-term CPAP adherence in obstructive sleep apnea patients are necessary and could be critical for optimizing comorbidity risk reduction,” Dr. Mazzotti said.
The study was presented at the virtual annual meeting of the Associated Professional Sleep Societies.
Good adherence important
The researchers analyzed the electronic health records of adults referred for a sleep study through the Kaiser Permanente Southern California health system. The sample included 11,145 adults without OSA, 13,898 with OSA who used CPAP, and 20,884 adults with OSA who did not use CPAP. None of them had CV disease at baseline. Median follow-up was 262 days.
The primary outcome was first occurrence of myocardial infarction, stroke, unstable angina, heart failure, or death caused by CV disease.
In adjusted models, adults with moderate to severe OSA (apnea-hypopnea index ≥15) who did not use CPAP were 71% more likely than those without OSA to have a first CV event (hazard ratio, 1.71; 95% CI, 1.11-2.64). However, the risk for a CV event during follow-up was 32% lower among OSA patients with any CPAP use (HR, 0.68; 95% CI, 0.50-0.93; P = .016).
The effect was mostly driven by those who used CPAP for at least 4 hours per night (HR, 0.60; 95% CI, 0.39-0.95). This association was stronger for those with moderate to severe OSA (HR, 0.56; 95% CI, 0.39-0.81).
“This study highlights the importance of long-term management of CPAP therapy in patients with moderate-severe OSA,” Dr. Mazzotti said in an interview.
“It suggests that maintaining good CPAP adherence might be beneficial for cardiovascular health, besides the already established benefits on quality of life, sleepiness, and other cardiometabolic functions,” he said.
Dr. Mazzotti said several mechanisms might explain the association between CPAP use and lower risk for CV events. “CPAP treats OSA by preventing respiratory pauses that occur during sleep, therefore preventing arousals, sleep fragmentation, and decreases in blood oxygen. These improved cardiorespiratory functions can be beneficial to avoid certain molecular changes that are known to contribute to cardiovascular risk, such as oxidative stress and inflammation,” he explained.
“However, specific studies fully understanding these mechanisms are necessary,” Dr. Mazzotti added.
In a comment, Nitun Verma, MD, a spokesperson for the American Academy of Sleep Medicine, said that “the frequent decreases in oxygen levels and fragmented sleep from apnea are associated with cardiovascular disorders. We know this from multiple studies. This, however, was a large study and strengthens the association between improving apnea and reduced serious cardiovascular events.”
Funding for the study was provided by the American Academy of Sleep Medicine Foundation and the American Heart Association. Dr. Mazzotti and Dr. Verma disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.