Modified OSA Index Score Associated With Cardiovascular Risk

Use of a modified sleep apnea index can identify cardiovascular risk factors in adults with moderate to severe obstructive sleep apnea (OSA), according to results from a new study presented at the American Academy of Otolaryngology–Head and Neck Surgery 2024 Annual Meeting.

The modified sleep apnea severity index (mSASI) combines patient anatomy, weight, sleep study metrics, and symptoms, to provide a more nuanced measure of OSA than the standard apnea-hypopnea index (AHI), said Jennifer A. Goldfarb, MHS, a medical student at Thomas Jefferson University, Philadelphia, Pennsylvania, who presented the findings.

OSA has an association with many negative cardiovascular comorbidities; however, “the AHI provides only a single metric and does not provide a holistic assessment of the individual patient’s disease severity,” said senior author Colin T. Huntley, MD, also of Thomas Jefferson University. 

“OSA is very complex, and having a robust system to assess the disease may be a better predictor of overall severity,” he told Medscape Medical News. 

Previous research has shown a correlation between mSASI and mean arterial pressure and serum C-reactive protein in OSA patients, but the connection with cardiovascular risk factors has not been well studied, Goldfarb noted. 

In the retrospective cohort study, Goldfarb and colleagues looked at mSASI scores from 260 CPAP-intolerant patients with OSA who underwent upper airway stimulation, maxillomandibular advancement, or expansion sphincter pharyngoplasty at a single sleep surgery clinic between 2014 and 2021. The mSASI uses a score of 1-3, with 3 as the highest level of OSA severity.

Cardiovascular risk factors were assessed at the patient’s initial evaluation by the sleep surgery team. They included coronary artery disease, type 2 diabetes, atrial fibrillation, congestive heart failure, hypertension, and cerebrovascular accident. 

A total of 142 patients (55%) had an mSASI of 1; 91 (35%) had an mSASI of 2; and 27 (10%) had an mSASI of 3. At least one cardiovascular risk factor was present in 58%, 68%, and 63% of these groups, respectively (P = .3). 

Stratifying participants by mSASI scores, the researchers found that patients with an mSASI of 2 or 3 were significantly more likely than those with an mSASI of 1 to have more cardiovascular risk factors on initial presentation, and were significantly more likely to be diagnosed with hypertension (P = .02 for both). 

Using the AHI, however, patients with moderate to severe OSA (AHI > 15) had a similar number of cardiovascular risk factors as those with mild OSA (P > .05). 

“A higher mSASI score, which represents worse disease, was associated with a higher Framingham risk score, which supported our hypothesis; however, the AHI was not found to be associated with an increased Framingham score,” Huntley told Medscape Medical News.

Takeaways and Next Steps

These results suggest that the AHI, while a good metric, might not be the best tool for assessment of overall disease severity, given the complexity of OSA, the impact of the disease on patient quality of life, and the risk for downstream cardiovascular disease, said Huntley. 

The findings were limited by the retrospective design and use of data from a single center. 

Population-level data are needed to identify variables that may be meaningful to create a future tool that provides the best picture of the individual patient’s disease, he added. Additional prospective data are also needed to assess the impact of the scoring system on long-term treatment outcomes. 

“The current study is especially interesting as we are just beginning to understand the factors that predict cardiovascular risk for patients with obstructive sleep apnea,” said Megan Durr, MD, of the University of California, San Francisco, in an interview. 

“For a long time, we primarily looked at the AHI and/or oxygen levels during sleep as risk factors, and we haven’t looked as much at other factors.” said Durr, who served as a moderator for the session in which the study was presented.

The current findings provide a more comprehensive look at cardiovascular risk; the inclusion of patient anatomy and symptoms add to the knowledge of this topic, and will lead to further work in this area, she added. 

The study received no outside funding. The researchers had no financial conflicts to disclose. Huntley disclosed receiving research support from Nyxoah and Inspire, and serving as a consultant for Nyxoah, Inspire, and Avivomed. 

Durr had no financial conflicts to disclose.