We have just completed the 25th Annual Advances in Diagnosis and Treatment of Sleep Apnea and Snoring course in Orlando, Florida. I wanted to share some interesting updates and new topics that I have not discussed previously, such as with my blog post about the 2018 course. I have truly enjoyed being a co-director of the course, where I have learned so much myself from the other faculty members. Although there are many excellent talks related to surgery, I thought I would focus on the non-surgical topics.
Telemedicine and Video Consultation
Samuel Kuna, MD spoke about his pioneering work showing the value of home sleep testing and telemedicine in enhancing access to care for patients with obstructive sleep apnea through the Veterans Affairs medical system. He and others (for example, Dennis Hwang, MD in the Kaiser Permanente system) have shown that it is possible to provide excellent care to patients while minimizing the need for patients to take time for in-person office visits. While an in-person examination is ideal for a thorough surgical evaluation, often I can obtain quite a bit of information through a video consulation (for example, on Skype) that can serve as an initial evaluation or as a follow-up discussion, especially in those who have to travel from a distance.
What to Do about Obesity and Obstructive Sleep Apnea?
Andrew Goldberg, MD, MSCE spoke about the microbiome, the microbes that we all have throughout our body. The microbiome of the digestive system has been studied most closely, and the functions include metabolism (particularly of fiber), protection from pathogens, and modulation and priming of the immune system. In particular, the microbiome can play an important role in inflammation throughout the body. The digestive tract microbiome does have an association with obesity, with a lower ratio of Bacteroides to Firmicutes in obese vs. lean individuals. While it is possible to change the microbiome in animals, the ability to change the microbiome in humans and to decrease obesity is not clear. There is an association between the nasal microbiome and obstructive sleep apnea, and a group of studies have shown that altering the digestive tract microbiome can lower blood pressure.
Gary Foster, PhD spoke about the connection between obesity and obstructive sleep apnea. He reiterated the fact that the most important behavioral changes for weight loss are a food diary (writing down what you are eating) and taking frequent weights (daily rather than weekly). As far as diets and weight loss programs, there does not seem to be a difference in long-term weight loss results with the composition of the diet, as it matters more how many calories are consumed. There may be other benefits of various diets, but from a weight loss perspective, the amount of calories is the key. There are a growing number of medications that are FDA-approved for long-term use in weight loss, and they have shown weight loss of about 10% in randomized trials. These medications do require continued use, but I share Dr. Foster’s enthusiasm for them, feeling that these are not used as commonly as they could. I certainly see weight loss playing an important role in results of surgery for sleep apnea, basically getting excellent results with a combination of weight loss and surgery that are not possible with either approach alone. Weight loss surgery has migrated to the technique of sleeve gastrectomy that achieves substantial weight loss and also can induce favorable changes in hormones that affect calorie intake.
4P Medicine and OSA
Dr. Pack has been a long-time proponent of personalized medicine or precision medicine, and this year he spoke of the P4 Medicine approach that has been advanced by Leroy Hood, MD, PhD. P4 Medicine involves the steps of Predictive, Preventive, Personalize, and Participatory. Dr. Pack has pioneered the identification of clusters of physiological subtypes (7) or clinical subtypes (3). As far as clinical subtypes of OSA, Dr. Pack has collaborated with a team in Iceland to identify those with insomnia (33%), not sleepy but with medical conditions like high blood pressure and diabetes (25%), and those with sleepiness and other symptoms (43%). Importantly, this work has been confirmed by the SAGIC international consortium in larger samples. This work has also highlighted the importance of sleepiness as being an indicator of those with an increased risk of cardiovascular disease related to OSA. Dr. Pack spoke of the fact that the sleepiness is not the issue but rather that OSA activates pathways that also contribute to cardiovascular disease. Atul Malhotra, MD spoke about the growing knowledge of what are called endotypes and the factors that contribute to OSA. This work is fascinating, and it holds tremendous promise for using medications or oxygen therapy in combination with surgery to improve results in patients who cannot tolerate positive airway pressure therapy (including CPAP). Right now this is limited to research settings, but ongoing research is trying to make this more available for patient care.
Weight Loss and Upper Airway Fat
Richard Schwab, MD has done high-quality research examining the deposition of fat and in other muscles around the throat in overweight individuals with obstructive sleep apnea, much more than in those of similar body mass index who do not have significant obstructive sleep apnea. At the course, he presented some upcoming research showing that weight loss – whether through nonsurgical or surgical approaches – results in a decrease in the size of the tongue and a decrease in tongue fat. There is also a decrease in the volume of the lateral pharyngeal walls, but the changes were not as dramatic (maybe related to the size of the study). Also, the change in the apnea-hypopnea index was related to the amount of fat loss in the tongue. This suggests that the fat deposition is actually reversible and that the fat is a key link explaining the connection between weight gain and obstructive sleep apnea. I certainly see this myself when patients have been able to lose weight, whether just on the office exam or with drug-induced sleep endoscopy, but Dr. Schwab’s work is much more detailed and confirms this scientifically.
Not All Sleep Apnea Is the Same
Allan Pack, MBChB, PhD spoke about some of the most important papers related to sleep from the past year. A group of papers have focused on the length of time that people have blockage in breathing in obstructive sleep apnea. Currently we define obstructive sleep apnea with a simple counting of apneas and hypopneas to generate the apnea-hypopnea index. Because some individuals have blockage in breathing for different periods of time, for example 10 seconds or 45 (or more) seconds, and the question is whether these differences in time are associated with differences in the effects of sleep apnea. Typically, longer apneas or hypopneas are associated with greater decreases in oxygen levels, and we have generally felt that longer events are worse. One study from the Wisconsin Sleep Cohort showed that events associated with low oxygen levels were associated with high blood pressure, while those not associated with low oxygen levels were associated with sleepiness. Another study from the Sleep Heart Health Study showed unexpectedly that shorter breathing events were associated with an increase in all-cause mortality, while another study showed that hypoxic burden was associated with cardiovascular mortality in older men.
Melatonin for Insomnia
Nalaka Gooneratne, MD, MSc spoke about several fascinating topics. He provided an update on complementary and alternative medicine. He summarized the evidence supporting the role of melatonin in treating insomnia, especially in adults over the age of 60. I was not aware of the existence of prolonged-release melatonin that may provide a longer period of time for benefit that could be especially helpful in those individuals with difficulty staying asleep through the night. This is marketed under the trade name of Circadin in Europe but is not available in the United States. I will be changing my own practice when I use melatonin for treatment of insomnia in older adults:
- standard formulations of melatonin, taken 2 hours prior to bedtime, for those with difficulty falling asleep
- standard formulations of melatonin, taken at bedtime, for those with difficulty staying asleep
- prolonged-release melatonin once it is available in the US
Sleep Wearable Technologies, Apps, and Machine Learning
Dr. Gooneratne then spoke about sleep-related wearable technologies and phone apps. One technology of particular interest is Beddr’s SleepTuner technology that performs well as a sleep study compared to polysomnograms and home sleep studies. While FDA-approved, he was not aware of its use in supporting insurance coverage for the test itself or for treatment of obstructive sleep apnea. I was part of a panel discussion at the course, where we agreed that simpler, cheaper testing for obstructive sleep apnea will be the way of the future for the majority of patients who have a high chance of obstructive sleep apnea. I expect that we will hear more about this technology and other similar approaches.
Ilene Rosen, MD, MSCE spoke about the application of machine learning to scoring of sleep studies. Machine learning involves use of computers that can learn to perform specific tasks. Reading an in-laboratory sleep study (polysomnogram) has always been considered beyond the abilities of computers, as there are simple (reading drops in oxygen levels) and complex (sleep stage determination) tasks. As series of studies over the past few years have shown that machine learning has shown excellent performance, suggesting that this may be coming in the not-so-distant future.
Sleep Apnea and Cognitive Decline
Dr. Gooneratne’s final talk discussed the importance of obstructive sleep apnea in adults over the age of 60. He has led important research showing that only those older adults with excessive daytime sleepiness (measured by the Epworth Sleepiness Scale) were at increased risk of mortality. He shared another study that highlighted the link between obstructive sleep apnea and cognitive impairment in older adults.