B (3:22)

So when a patient has a sleep study done, they measure these apneas and hypopneas, and they measure them over the entire tracing, which would be normally around seven or eight hours or so. And the amount of these apneas and hypopneas you have divided by the time that you spent in sleep will give you what's called the apnea hypopnea index, which is the average of these apneas and hypopneas per hour.

A (3:47)

So that makes sense. So we get an average per hour. Give us a sense, and we'll talk more about this one, our next episode when we talk about how to interpret sleep studies. But give us a sense at this point, what is considered normal, if there's a normal amount, what is considered mild, moderate and severe apnea hypopnea index.

B (4:09)

So really, in a sense, there's no apneas or hypopneas that are good for you. But what we currently have our settings on is 5 to 15 apnea hypopnea index, which again is the average between 5 to 15 apnea hypopneas per hour. 5 to 15 is considered mild OSA, 16 to 30 is considered moderate OSA, and over 30 is considered severe. Those that are that have higher numbers will experience more problems associated with osa.

A (4:42)

Excellent. And let's shift now to pathophysiology, because I think this is often puzz. Why do some people have osa?

B (4:52)

The pharynx and the hypopharynx are pliable tubes. In humans, they're pliable, and the reason for that has a lot to do with the fact that we can make our inflections and voices and that sort of stuff. In other animals, they're either cartilaginous or bone, but in humans, they are pliable tubes lined with muscle and fat. And the tube becomes obstructed due to collapsing from lying down during sleep, and also the tongue falling back into it. So the smaller the airway, which means the more the fat and just the way that you're built, the more the possibility of an obstruction actually happening.

A (5:29)

So we know that this is more common in people with obesity. When we think about obesity, we think about fat distribution for cardiovascular risk. We often talk about it as an abdominal fat. But with regard to osa, is there actually fat deposition around that cartilaginous area around our airway.

B (5:50)

Absolutely. And in fact, we know that the more weight that a person carries, the more likely they are to develop obstructive sleep apnea. And we'll talk about this a little bit more as time goes on. But the more fat deposition there is, the lesser or smaller the airway. And as a result of that, there is more collapsibility and less of an airway that is present during sleep. And as a result, the person is going to have more apneas and more hypopneas. Ostensibly, then the more fat that you have in your body, the more obese that you are, the more likely you are to develop obstructive sleep apnea.

A (6:24)

That makes sense. That really links what's going on systemically to the outcome we're talking about today, obstructive sleep apnea. Can you talk now a bit about the epidemiology of OSA?

B (6:35)

Yeah. We've known about obstructive sleep apnea for 50 years or greater. And as time has gone on, we've done a lot of studies, a lot of epidemiologic studies to understand how prevalent is this condition. Is it something that just occurs now and then? Is it something that we really need to be concerned about, or is it something that really is a problem? All the way back when, in 1994, there was a New England Journal of Medicine that did a really valuable study that showed that patients, or people, rather, not patients, but people, average person, you put them in a sleep laboratory, and if they have obstructive sleep apnea, people that had an AHI of 5 or greater, in men, it was 26%. In women, it was 13%. So the average person that's running around in the United States in 1994, in men, they had a 1 in 4 chance of obstructive sleep apnea. And in women it was something like 1 in 9. And that's been increasing over time.

A (7:34)

So, Paul, the study really was startling. I believe they used an apnea hypopnea score fiverr higher to define the prevalence of sleep disordered breathing, which was, as you said, 9% for women, 24% for men. The prevalence decreased when they used a combination of an AHI of 5 or higher along with daytime hypersomnulants as the diagnostic criteria for sleep apnea syndrome. The prevalence of OSA in the US has really increased a lot over the last few years. And there's a range of prevalences out there to. Depending on what study you read. I know it was estimated in a recent article in JAMA to be about 15% for men and 5% for women with moderate to severe OSA accounting for a large proportion of that number.

B (8:32)

That was a general population, Neil, and that's an important point which says that it's very prevalent in all Americans and all people, adults in this country. So it's quite prevalent. Now, I should also say that if you take the aa, the apnea hypopnea index, and you make the cutoff at 15 per hour, that becomes a little bit less prevalent, but nonetheless, it's still highly prevalent in the average person that comes to us in primary care.

A (8:58)

And do you have a sense of the prevalence in higher risk groups, either people with obesity or people with diabetes?

B (9:07)

Yeah, actually we need to be a little bit more attentive to the possibility that obstructive sleep apnea is occurring in certain populations. We know, for example, that culturally we should say that most countries have about the same amount of obstructive sleep apnea. But Pacific Islanders, because of their anatomy, have more obstructive sleep apnea. Asians also have a little bit more obstructive sleep apnea, but because their BMIs tend to be a little bit lower than Europeans and Americans, the rates of obstructive sleep apnea are similar in Asians and Europeans and Americans. Now, I should also say that when you take a different populations, there's this bidirectionality to different conditions for obstructive sleep apnea. So, for example, congestive heart failure, coronary artery disease, stroke, and you mentioned this earlier, obesity and type 2 diabetes. But also in depression, there is a bidirectionality of obstructive sleep apnea, meaning that if you have those conditions that I just mentioned, you're more likely to develop obstructive sleep apnea. But the other way is also true, which is if you have obstructive sleep apnea, you're much more likely to develop those conditions that I just mentioned, a bidirectionality then with the comorbidities and obstructive sleep apnea specifically. You also mentioned obesity, and that's a very important point because 70% of patients are obese who have obstructive sleep apnea. Now, if you take it the other way around, if the person is obese, they have about a 40% chance that they will have obstructive sleep apnea. But if you take people who have obstructive sleep apnea, 70% are obese. Now that should also alert you to the fact that 30% of people with obstructive sleep apnea are not obese. And that talks about the anatomy, and we'll talk about the anatomy a little bit more later on. When you look at somebody's throat, what does that look like? Do they have a crowded pharynx? But these are some of the differences in different populations. One other thing I should say you talked about diabetes. Diabetics are three times more likely to have obstructive sleep apnea. But also, if you have obstructive sleep apnea, it is a risk factor for diabetes in and of itself.

A (11:16)

So it's pretty clear that it's common and it's important. How are we doing with regard to diagnosis? Do studies show that we're pretty good at making the diagnosis or is it otherwise?

B (11:28)

Most recent evidence is suggesting that, unfortunately, 80 to 90% of people with OSA remain undiagnosed despite receiving adequate access to healthcare. So a large portion of people with obstructive sleep apnea are undiagnosed, and there are many reasons for that possibly occurring as a result of patients not coming in with symptoms. Very suggestive. And maybe we're also not very attuned to the possibility of a patient with obstructive sleep apnea. Or maybe we're unaware of the connection between the medical conditions that I just mentioned earlier that are very prevalent, the connection between those and obstructive sleep apnea. As a result of all these, again, the majority of people with obstructive sleep apnea continue to remain undiagnosed.

A (12:14)

So that's important. So let's move on now to clinical presentations. How does OSA usually present and what should we have our antenna up for in order to think about making the diagnosis?

B (12:27)

Yeah. So as I've already said, most cases are undiagnosed because patients don't come in with glaring symptoms like, hey, doc, I stopped breathing in my sleep. They don't say that. And by the way, even if they do, a lot of primary care providers are still not totally keen on sending patients for testing and diagnosing it. But nonetheless, the majority of patients go undiagnosed because they don't have glaring symptoms. But let me give you some clues, okay? A patient with loud snoring. Now, typically when that happens, they have a bed partner that comes in and says, my partner or my spouse or whatever snores very loudly. And it really bothers me. Now, they don't usually come to their primary care doctors complaining of it, but if they do, that is one of the clinical symptoms. Also, the bed Partner may say that the person stops breathing in their sleep. Sometimes that happens. Not very often, but it sometimes happens, especially if the bed partner is keen on the condition of obstructive sleep apnea. Choking or gasping during sleep is a glaring problem. If a patient says to you, sometimes I wake up in the middle of night because of choking and gasping, that person has obstructive sleep apnea until proven otherwise. Morning headaches, Morning dry mouth, morning sore throat. Have you ever had a patient that comes in saying to you, doc, I wake up with a headache every morning. It goes away. That's due to, by the way, hypercapnia. Too much carbon dioxide causes headaches. So morning headaches are a problem. Morning dry mouth, Like I said, waking up and the mouth is really dry. Maybe they say, my tongue is stuck to the roof of my throat or a sore throat that eventually go away after the morning subsides. Another thing, Neil, is insomnia. Now, in patients that come in any situation, in my opinion, we should get a good sleep history. When patients come in for a complete physical, we should always get a good sleep history. The person who wakes up many times throughout the night, they wake up typically with not that much of a problem getting back to sleep again, but they wake up a lot. And that type of insomnia is associated with obstructive sleep apnea, probably because of the sleep fragmentation occurring as a result of the apneas and hypopneas. Another one, though, is enuresis. Wetting the bed. Have you ever had a patient come to you that says, hey, doc, I'm really embarrassed to say this, but I'm wetting the bed? I have no idea why I've not had this before, but it's happening now. It's not very common, but if it does happen, that may be a clue that the patient has obstructive sleep apnea. Nocturia. A lot of our patients have nocturia. Typically we think of maybe overactive bladder or prosthetism or that sort of stuff. But do we ever consider the possibility that this could be obstructive sleep apnea? Finally, and probably the most concerning symptom to us, because it has a lot of serious safety consequences, is daytime fatigue or tiredness, specifically what we call excessive daytime sleepiness. In patients that have this drowsiness that occurs during the day, they're much more likely to have this happen when they're driving, and that could be a serious, hazardous problem. Or if they're operating heavy machinery, it could be a serious, hazardous problem. So daytime fatigue or daytime tiredness, excessive daytime sleepiness. These are some of the clinical symptoms that patients can have that we should think about the possibility of obstructive sleep apnea.

A (15:42)

Those are great points, Paul. And it really takes a high index of suspicion because I very seldom see someone who when I ask, says, oh, I have a great energy level. Everyone I know is working too hard. Every one of my patients work too, too hard. They have kids, they have an extra job outside of their regular job. But there's a different character to that daytime sleepiness that at least sometimes you hear when someone has osa. Let me ask you about a couple of other things that perhaps we should be alert to. What are your thoughts around thinking about OSA with resistant hypertension, which actually a third of our patients who have hypertension are not controlled on two or three medicines or difficult to control diabetes.

B (16:25)

When we talk about clinical symptoms or presentation or patients coming to our office where we have to have a higher index of suspicion, There are many medical conditions that we should have our antennas going up to think about obstructive sleep apnea. One of them is in fact resistant hypertension. Think about somebody, for example, that has 2, 3, 4 blood pressure medications and they are still uncontrolled. Depression, coronary artery disease, stroke, atrial fibrillation. There's all these different kind of things that we should have a higher index of suspicion of the possibility of obstructive sleep apnea. And we should get a good history on our patients, especially a good sleep history, and also then understanding if they have daytime sleepiness. And I didn't mention this, but one of the ways of measuring excessive daytime sleepiness is something called an Epworth Sleepiness Scale. Epworth Sleepiness Scale, otherwise known as ess. It is a very valuable tool that we use in sleep laboratories, but also in, in clinical studies to understand how drowsy somebody actually is. And if you look at the ess, what you're doing is you're asking the person, how drowsy are you in normal everyday life as a passenger in a car or driving a car, or resting in the afternoon without any alcohol or speaking to someone or watching TV or being, let's say, in a, in an environment such as a church or a waiting room or that sort of stuff, how likely are you to get drowsy and nodd? Very key indicator of excessive daytime sleepiness. But again, getting back to the point that you mentioned, yes, there are many conditions where when patients come into our office, we should be at a higher alertness level to think about the possibility of obstructive sleep apnea.

A (18:09)

Paul it's pretty clear. The diagnosis sometimes is dramatic. The presentation is dramatic, but sometimes it's subtle. We'll talk more about diagnosis in our second episode. But it sounds that taking a good sleep history is always important. When you're concerned, you do the Epworth sleep score or some other validated study and the brief version, we'll expand more on it. Next episode is how do you decide when to send someone for a sleep study?

B (18:38)

One of the most valuable tools that I think everybody should get to know is called the Stop Bang screening tool. S, T, O, P, B, A, N, G. Very validated screening tool for obstructive sleep apnea where you ask the person S, T, O, P, B, A, N, G. It's A, it's, it stands for eight different situations or conditions. The S stands for snoring, T for tiredness, O for observed stop breathing, P for blood pressure, B for BMI greater than 35, A for age greater than 50, neck for neck size greater than 17 inches for a male and greater than 16 inches for a female and gender G for gender male. Now, if anybody has three or more of these positive, the probability of obstructive sleep apnea is around 85%. In a lot of other situations we try to get 5 or more positive on a stop bank. That person has 95 probability percent probability of obstructive sleep apnea. So what I'm suggesting here is if somebody comes to you and you think about the possibility of obstructive sleep apnea, do a stop bang analysis on them and if they have three, four or even five of them positive, you say to the person, you know what? You are very highly likely to have obstructive sleep apnea. I'd like to send you for testing. And the testing can either be in a sleep laboratory or it can be at home, which you'll cover at some later stage. But still, a Stop bank screening tool can be very helpful. Another one, by the way, is called the Mallampatti class of oral assessment. When somebody opens their mouth and sticks their tongue out without saying ah, if you look there and you can see what's going on, you can get an assessment about the probability of obstructive sleep apnea. So if you see the uvula, the pharynx, the hypopharynx and the tongue, you can see that nicely. That's called the Mallampati Class 1 shifting all the way to a Class 4. There's also Class 2, 3. But if we look at Class 4, it is when somebody opens their mouth, you see the tongue and the roof of the mouth and you don't see the uvula, you don't see the hypopharynx, you don't see the pharynx. That's a MAP class four, which has an eight times higher probability of obstructive sleep apnea. So these are some of the ways that we can understand what are the likelihoods of this patient have obstructive sleep apnea and whom do we send for testing?

A (21:02)

That is so helpful, Paul. Now, we've talked about the symptoms, we've talked about who to send for symptom. Rather we've talked about symptoms, we've talked about who to send for testing. Can we just step back for a moment and talk about why we care again? What are the consequences of os?

B (21:20)

That's the important thing. Now we've already talked about, Neil, that this is very prevalent. That's one reason why we should be on the lookout for it. But take a look at the symptoms. For example, daytime sleepiness, like I said, leading to car accidents and industrial accidents. It's quite sobering to just understand that these patients are drowsy. They also have cognitive impairment and a decreased quality of life. These patients are not enjoying life as much. Why are we in primary care? We want to help our patients to the best quality of life for the longest duration possible. And OSA degrades quality of life. It degrades interpersonal relationships, romantic relationships. These people don't really feel like doing anything. They're tired throughout the day. So one reason then is symptoms. But the second reason is medical problems. We've already talked about this, but let me say it again because it's so important to reiterate. Hypertension, especially resistant hypertension, congestive heart failure, stroke, heart attack, type 2 diabetes, depression, especially resistant depression. Have you had a patient, for example, who comes in and you have them on an antidepressant? They're not getting better. A lot of times we think we should change the medication or add a medication. Have you thought about doing a sleep history or a stop bang on them to see if they have obstructive sleep apnea and that's what's causing their resistant depression, atrial fibrillation. 50% of patients with atrial fibrillation have obstructive sleep apnea. And nowadays a lot of cardiologists are sending patients back to primary care or sending them to the sleep center saying, hey look, I got a patient here with atrial fibrillation. 50% of them have obstructive sleep apnea. Do a test to see if they have that or not. Reflux, especially bad reflux, resistant to treatment, and finally, overall decreased life expectancy. These patients don't live as long. So there are so many important reasons to identify and manage obstructive sleep apnea.

A (23:15)

So, Paul, there's lots of consequences. And the question we always ask in medicine is, okay, there are consequences addressing root cause. Does it make a downstream difference? What's the answer for osa?

B (23:31)

That's such an important question. Is intervening going to make any difference at all? And the answer to that is yes, a big difference. We know that. And by the way, we all also know probably that the most common treatment for obstructive sleep apnea and relieving the obstruction in relieving the hypopneas is positive airway pressure. Whether it's continuous positive airway pressure, CPAP or whether it's bile level, positive airway pressure, BiPAP or whether it's, it's autoregulated Pap, which is called auto Pap. All these do help improve the patient's situation. Whether it's hypertension, whether it's daytime sleepiness, whether it's cognitive performance, whether it's heart function, like in congestive heart failure or right side heart failure, which is another consequence, by the way, or longevity. Living longer. We know that when we intervene with relieving the obstruction, people feel better, their comorbidities improve and they live longer. Now, one of the other things that I should say, I mentioned positive airway treatment. We know that just plain weight loss makes a difference. We know, for example, that the recent studies came out with tirzepatide, which is indicated for diabetes as well as weight loss. We now know that this medicine, tirzepatide, is indicated for obstructive sleep apnea. Where when patients have obstructive sleep apnea and obesity and they take this medicine, that can help improve the situation as well.

A (24:54)

This is really helpful. Paul, we're about out of time. Are there any final thoughts that you'd like to share with our listeners?

B (25:01)

Yeah, Neil, Obstructive sleep apnea, we all need to know as medical providers, is very prevalent. But also with the comorbidities that I mentioned, is much more likely. We need to identify them, stratify them, treat them and get them better. We're all about helping our patients to reduce towards better quality of life and longevity. And by diagnosing sleep apnea, by remedying it, we can make a significant difference in quality of life and longevity in our patients.

A (25:29)

That's a great summary. Dr. Paul Dugramji, thank you so much for joining us.

B (25:34)

My pleasure, Neil.

A (25:36)

And most of all, of course, to our listeners. Thank you for joining us on this first of a multi part series on obstructive sleep apnea. I think we've all learned a lot today about obstructive sleep apnea. We've learned how common it is, how important it is, how many downstream consequences there are. And we've touched on both diagnosis and treatment, both with CPAP and tirzepatide. We'll be talking more on future episodes. In the second episode, we'll focus on making the diagnosis and interpreting the results of those sleep studies. In the third and fourth episode, we'll do a deep dive on treatment options and then some cases where we can tease out what option is best for which patient. This special series of Diabetes Core Update is sponsored by Lilly. We thank you for listening. For the American diabetes association, I'm Dr. Neal Skolnick. Till next time, stay safe and keep learning.

B (26:38)

Sam.