Another year has come and gone, and our 20th annual Advances in Diagnosis and Treatment of Sleep Apnea and Snoring course started today in San Francisco. As a Co-Director, it is exciting to have close to 200 attendees again, a testament to the recognition of the importance of sleep apnea and snoring as well as the growing body of knowledge that keeps the course interesting and new every year. Here are some of the highlights from today.
Atul Malhotra, MD from the University of California, San Diego discussed the causes of sleep apnea. Atul presented the fascinating work done with his teams in San Diego and when at Brigham and Women’s Hospital on the substantial differences between patients in the factors that contribute to sleep apnea (anatomy, muscle control, breathing control, arousal threshold, and lung volume). In addition, he showed data published in the American Journal of Epidemiology, coming from the Wisconsin Sleep Cohort Study and a national survey in the United States (NHANES), indicating that 6% of women and 13% of men have at least moderate obstructive sleep apnea, defined by an apnea-hypopnea index of 15 or more events per hour. A later talk discussed the clear evidence that CPAP achieves major benefits in patients that can wear it and sleep comfortably while wearing it.
Sam Kuna, MD from the University of Pennsylvania spoke about the link between cardiovascular disease and obstructive sleep apnea, especially for severe obstructive sleep apnea. The clearest evidence suggests that it is the increase in sympathetic nervous system activity (such as adrenaline levels) occurring with sleep apnea that contributes to cardiovascular disease, whether hypertension, myocardial infarction (heart attack). Sam is one of the leaders in the systematic evaluation of home sleep study technologies, and he delivered an intriguing and thoughtful talk on ambulatory management of sleep disordered breathing (including snoring and sleep apnea). The bottom line is that sleep disordered breathing is common, and laboratory testing (polysomnography) and initiation of positive airway pressure therapy (CPAP titration studies) has become so expensive that many have called for a shift to home sleep studies and an ambulatory treatment strategy like automatically-adjusting positive airway pressure therapy. At this point, multiple studies have shown that ambulatory management produces similar outcomes to in-laboratory management in controlled settings (university centers, in-office evaluation of patients before sleep studies). Additional research will determine whether the same is true when applied in a variety of clinical settings, as these may revolutionize the practice of sleep medicine.
Sleep apnea: it is more than just the AHI
There is a natural tendency to focus on the apnea-hypopnea index or other sleep study measures in order to determine whether we are treating patients effectively. However, patients are more than just this single number. Andrew Goldberg, MD, MSCE from the University of California, San Francisco highlighted the array of measures that can characterize obstructive sleep apnea. Patients present for treatment because of how they are affected, and there are many other ways that we could think about defining sleep apnea and the effects of treatment: the degree of snoring, sleepiness, quality of life effects, hypertension or cardiovascular disease, or metabolic consequences like insulin resistance. Interestingly, some studies have found that some of the “soft” measures like sleepiness may identify groups at greatest risk of “hard” health consequences like hypertension and mortality. Similar to the care of patients with diabetes, where physicians look more at hemoglobin A1c rather than a simple glucose level for long-term control of diabetes, we need a better measure of evaluating the long-term control of sleep apnea other than an apnea-hypopnea index from a single night that can only be measured with a somewhat-expensive sleep study.
Jolie Chang, MD spoke about the impact of snoring on social relationships as well as health, building on the studies and themes that we have described in a previous paper and a previous entry on this blog. The evidence is not yet clear, and further research may evaluate the extent to which we have to think about health effects in weighing the urgency for treating snoring.
There are a number of technologies that can monitor CPAP use, and increasingly confirmation of CPAP usage is required for CPAP reimbursement. Richard Schwab, MD of the University of Pennsylvania presented the available methods of CPAP adherence tracking and some approaches for their use in the long-term management of obstructive sleep apnea. Rich also discussed his research related to upper airway imaging and the insight that it has offered to understanding changes in the head and neck region in patients with sleep apnea, including those with weight gain.
New developments in obesity and obesity treatment
Gary Foster, PhD, formerly of Temple University and now the Chief Scientific Officer of Weight Watchers International, spoke about obesity, weight loss, and sleep apnea. He discussed the Sleep Ahead study of obese patients with non-insulin-dependent diabetes, in which 87% of patients had obstructive sleep apnea but relatively few would proceed with treatment of sleep apnea. Fortunately, intensive lifestyle interventions (increased physical activity) and successful weight loss could achieve mild improvements in sleep apnea, with greater benefit for those who were able to lose more weight–although there was benefit related to physical fitness above and beyond weight loss. Gary also discussed the recently-published small randomized trial of Qsymia showing a reasonable degree of weight loss and substantial improvement with sleep apnea, emphasizing that this was encouraging evidence that would benefit from a larger study.
Breathing through the nose is important for sleep apnea, especially in using a treatment like CPAP that can deliver air through the nose. Edward Weaver, MD, MPH of the University of Washington has performed research funded by the National Institutes of Health in this area. He discussed the evidence demonstrating that nasal obstruction decreases CPAP use and that treatment of nasal obstruction increases CPAP use. This course is designed to provide overlap between different groups of providers that treat sleep apnea, and the nose is certainly one area that surgeons and non-surgeons work together closely. Of course, surgery is not the only option to treat nasal obstruction, but surgery can address nasal obstruction that does not respond to medications alone.
After a full day, I am looking forward to the continuation of the program tomorrow.