Sleep apnea is a serious condition that affects millions of people, interrupting their breathing during sleep and leading to loss of deep sleep, resulting in a host of health issues. And treatments like CPAP therapy are common.

But new research has found that certain treatments such as hypoglossal nerve stimulation, may be more effective in specific groups. Notably, individuals who are overweight but not severely obese seem to benefit the most.

What Does the Research Say About Hypoglossal Nerve Stimulation and BMI?

Hypoglossal nerve stimulation (HGNS) has emerged as a promising alternative treatment for obstructive sleep apnea (OSA). Especially for patients who struggle with or cannot tolerate continuous positive airway pressure (CPAP) therapy.

A recent retrospective study  conducted at the Washington University Medical Center in St. Louis, Missouri, sought to investigate the efficacy of HGNS and the influence of body mass index (BMI) on treatment outcomes. Here’s what the research reveals.

Is Hypoglossal Nerve Stimulation Effective for OSA?

The study included 76 adult patients with OSA who had been implanted with HGNS devices between 2019 and 2023. The primary outcome measured was a reduction in the apnea-hypopnea index (AHI). Which quantifies the severity of sleep apnea. A successful treatment response was defined as a ≥ 50% reduction in pre-implantation AHI and a post-implantation AHI of fewer than 15 events per hour.

Key findings

Researchers found 77.6% of the patients (59 out of 76) achieved a successful treatment response. The median AHI significantly decreased from 29.3 events per hour before implantation to 5.3 events per hour post-implantation. Indicating a Hodges-Lehman difference of 23.0. These results highlight the effectiveness of HGNS in significantly reducing the severity of OSA in a majority of patients.

How Does BMI Influence the Response to HGNS?

BMI appears to be important in the efficacy of HGNS. The study’s multivariable logistic regression analysis revealed that patients with a BMI between 32 and 35 had 75% lower odds of responding to HGNS compared to those with a BMI of 32 or lower (odds ratio [OR] = 0.25;  95% confidence interval [CI] = 0.07–0.94).

What does this mean?

Higher BMI was associated with a decreased likelihood of achieving a successful treatment response. Specifically, individuals with a BMI over 32 were less likely to experience the significant reductions in AHI that are indicative of effective HGNS treatment. So this suggests that while HGNS can be highly effective for OSA patients, its efficacy diminishes as BMI increases beyond this threshold.

Does Supine Sleep Position Affect HGNS Efficacy?

The study also examined the impact of sleeping position on HGNS efficacy, particularly focusing on patients who predominantly slept in a supine position (on their back).

Out of 44 patients who slept supine 17 (39%) achieved a successful treatment response. For these patients, the median AHI in the supine position decreased from 46.3 events per hour pre-implantation to 21.8 events per hour post-implantation, with a Hodges-Lehman difference of 22.0.

Adjusted analysis findings

The adjusted analysis suggested an association between higher BMI and lower odds of responding to HGNS when considering supine AHI treatment response (OR = 0.39, 95% CI  = 0.04-2.59).

However, the wide confidence interval indicates imprecision, making it difficult to draw definitive conclusions about the impact of BMI on HGNS efficacy in supine sleepers.

Clinical Implications and Future Research

This study underscores the importance of considering BMI when evaluating patients for HGNS therapy. Patients with a BMI over 32 may have lower odds of benefiting from HGNS.

And this should be communicated during patient consultations. Additionally, those who sleep in a supine position may experience reduced efficacy though further research is needed to clarify this relationship.

Future directions

The study’s findings highlight the need for larger, more diverse cohorts in future research to better understand the nuanced effects of BMI and sleep position on HGNS outcomes. Such studies could facilitate the optimization of HGNS treatment strategies and improve patient counseling, ensuring that those most likely to benefit from the therapy are accurately identified.

Disclaimer: Please note that the information shared here is for educational purposes and should not be used as a substitute for medical advice. Consult with a healthcare provider for any medical concerns.

How Does Body Mass Index (BMI) Influence Obstructive Sleep Apnea (OSA)?

Body Mass Index (BMI) is important in the development and severity of obstructive sleep apnea (OSA). OSA occurs when the airway becomes partially or completely blocked during sleep, causing breathing to stop and start repeatedly. The relationship between BMI and OSA is well-documented, with studies showing a direct correlation between higher BMI and increased risk of OSA.

Why is this?

Excess body weight, particularly around the neck and upper airway, can contribute to airway obstruction. Fat deposits in these areas can put pressure on the airway, making it more likely to collapse during sleep. For example, a study published found that a 10% weight gain can increase the risk of developing moderate-to-severe OSA by six times.

Statistics to consider

According to the Obesity Medicine Association, approximately 70% of individuals with OSA are obese. As BMI increases, so does the severity of OSA. For instance, individuals with a BMI of 30 or higher are more likely to experience severe OSA, characterized by more than 30 apnea events per hour. This increase in BMI not only heightens the risk but also worsens the symptoms. Leading to more pronounced daytime sleepiness, fatigue, and other related health issues.

Why does this matter?

Understanding the influence of BMI on OSA is important for both prevention and treatment. Weight loss even a modest 5-10% reduction, has been shown to significantly improve OSA symptoms. In some cases, it may even eliminate the condition altogether. This emphasizes the importance of weight management as a primary intervention for individuals at risk of or currently dealing with OSA.

What Is Hypoglossal Nerve Stimulation, and How Does It Work?

Hypoglossal nerve stimulation (HNS) is an innovative treatment option for obstructive sleep apnea. Particularly for those who cannot tolerate continuous positive airway pressure (CPAP) therapy. The hypoglossal nerve controls the muscles of the tongue. Which is important in maintaining an open airway during sleep.

How does it work?

The HNS system consists of a small device implanted under the skin in the upper chest. This device monitors breathing patterns and stimulates the hypoglossal nerve during sleep. The stimulation prompts the tongue to move forward. Which helps keep the airway open, reducing the number of apnea events. The system is usually controlled by a remote that allows the patient to turn it on before sleep and adjust the stimulation levels as needed.

Considerations:

While HNS is a promising treatment for OSA, it is not suitable for everyone. Candidates must undergo thorough evaluation. Including a sleep study and airway assessment, to determine if they are likely to benefit from the therapy. Moreover, the implantation procedure, though minimally invasive requires a surgical intervention and potential candidates must weigh the benefits against the risks.

Is Hypoglossal Nerve Stimulation the Right Choice for You?

Determining if hypoglossal nerve stimulation (HNS) is the right choice for you depends on several factors. Your BMI, sleep position, and overall health are important in how effective this treatment might be.

While HNS can significantly reduce symptoms of obstructive sleep apnea (OSA), especially for those who struggle with CPAP therapy, it’s not a one-size-fits-all solution. Speaking with a sleep expert or your doctor is essential to understanding whether HNS is a suitable option for your specific condition.

At The Insomnia and Sleep Institute of Arizona, we offer Inspire therapy, a mask-free, second-line treatment for moderate to severe OSA. Inspire (hypoglossal nerve stimulation) is ideal for individuals who cannot tolerate PAP therapy. This innovative system. Which includes an implant, remote, and app empowers you to control your OSA treatment easily.

Interested in learning more? Contact us today to know how Inspire therapy could be the solution you’ve been searching for.

References:


Emily Jane Meyer, & Gary Allen Wittert. (2023). Approach the Patient With Obstructive Sleep Apnea and Obesity. The Journal of Clinical Endocrinology & Metabolism, 109(3), e1267–e1279. https://doi.org/10.1210/clinem/dgad572

Kuldeep Patial, Hara Prasad Mishra, Pal, G., Tarun Kumar Suvvari, Ghosh, T., Smruti Sikta Mishra, Mahapatra, C., Amanullah, N. A., Shukoor, S. A., Kamal, S., Singh, I., Juveriya Israr, Sharma, P. S., Gaur, S., & Behera, R. K. (2023). Understanding the Association Between Obesity and Obstructive Sleep Apnea Syndrome: A Case-Control Study. Cureus. https://doi.org/10.7759/cureus.45843

‌Obesity and Obstructive Sleep Apnea. (2017). Obesity Medicine Association. https://obesitymedicine.org/blog/obesity-and-sleep-apnea/

Patel, R. M., Wang, H. Z., Jamro, E. L., Lindburg, M. R., Jackson, R. S., Malhotra, R. K., Lucey, B. P., & Landsness, E. C. (2024). Response to Hypoglossal Nerve Stimulation Changes With Body Mass Index and Supine Sleep. JAMA Otolaryngology–Head & Neck Surgery, 150(5), 421–421. https://doi.org/10.1001/jamaoto.2024.0261

Disclaimer: The information provided in this blog post is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always consult with a licensed healthcare provider for recommendations specific to your individual health needs.