CPAP Therapy Found to Reduce CVD Risk in Patients With Prediabetes, OSA

Continuous positive airway pressure (CPAP) treatment administered at night was found to lower daytime resting heart rates and reduce the risk of cardiovascular disease (CVD) in patients with prediabetes who have obstructive sleep apnea (OSA), according to study findings published in the Journal of the American Heart Association.

As researchers of the study highlight, the link between OSA and CVD has been widely recognized, but there remains an unmet need for therapies to address these comorbid conditions.

"The majority of patients don't make a connection as to how their sleep can affect their hearts. With regards to their sleep apnea, patients just think how sleepy they are the next day," said study author Esra Tasali, MD, director of the Sleep Research Center at the University of Chicago Medicine, in a statement. "I always explain to my patients that sleep apnea can also be harmful to their cardiovascular health."
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Moreover, the prevalence of another condition, prediabetes or diabetes, has been estimated to occur in 50% to 70% of OSA cases. Along with those who have CVD, patients with diabetes are among the most vulnerable to coronavirus disease 2019. "Any way we can improve cardiovascular health is more important than ever these days," said Tasali.

In prior randomized controlled studies examining the efficacy of CPAP therapy, no clear cardiovascular benefit was observed. The study authors attributed this finding to poor adherence.

They sought to further examine the potential benefits of CPAP therapy by conducting a novel study to assess daytime resting heart rate, a strong predictor of adverse cardiovascular outcomes and mortality.

In the randomized controlled study, they recruited 39 participants with OSA and prediabetes, who received either in‐laboratory, all‐night CPAP therapy (n = 26) or placebo (n = 13) for 2 weeks. Of the study cohort, 72% were obese, 82% had moderate to severe OSA, and 46% reported excessive daytime sleepiness. Resting heart rate was continuously assessed over 19 consecutive days and nights via ambulatory device consisting of a single‐lead electrocardiogram and triaxis accelerometer.

Based on study findings, those placed in the CPAP group exhibited reduced daytime resting heart rate compared with the placebo group (treatment difference = −4.1 beats/min; 95% CI, −6.5 to −1.7 beats/min; P = .002). Speaking on the reduction in resting heart rate observed, Tasali noted that a drop of even 1 beat per minute can lower the mortality rate and future risk of developing CVD.

"A 4- to 5-beat-per-minute drop in heart rate that we observed is comparable to what you would get from regular exercise," added Tasali. "Our breakthrough finding is the carryover of the lowered resting heart rate into the daytime and the cardiovascular benefit of that."

In additional findings, the magnitude of reduction in daytime resting heart rate after treatment was indicated to significantly correlate (r) with the magnitude of decrease in plasma norepinephrine, a marker of sympathetic activity (r = 0.44; P = .02), and the magnitude of decrease in OSA severity:

• Apnea‐hypopnea index (r = 0.48; P = .005)
• Mxygen desaturation index (r = 0.50; P = .003)
• microarousal index (r = 0.57; P < .001)
  

“This proof‐of‐concept randomized controlled study demonstrates, for the first time, that CPAP treatment, when optimally used at night, reduces resting heart rate during the day, and therefore has positive cardiovascular carry over effects,” the study authors concluded. “These findings suggest that better identification and treatment of OSA may have important clinical implications for CVD prevention.”

Reference

Pamidi S, Chapotot F, Wroblewski K, Whitmore H, Polonsky T, Tasali E. Optimal continuous positive airway pressure treatment of obstructive sleep apnea reduces daytime resting heart rate in prediabetes: a randomized controlled study. J Am Heart Assoc. Published online October 1, 2020. doi:10.1161/JAHA.120.016871