Sleep Disorders and Rheumatoid Arthritis

More than 50% of patients with rheumatoid arthritis (RA) suffer from sleep fragmentation and obstructive sleep apnea, which effectively results in poor quality of sleep. Do patients with RA also suffer from restless leg syndrome? Is there any treatment or medication? Dr Patricia Katz explains.

Patricia Katz, PhD, is a professor of medicine and health policy at the University of California San Francisco.

TRANSCRIPT:

RALN:

Welcome to this podcast from the Rheumatology & Arthritis Learning Network. My name is Priyam Vora, and today we are talking with Dr. Patricia Katz from the University of California, San Francisco, about recent research she and colleagues conducted on sleep disorders among patients with rheumatoid arthritis. Thank you, Dr. Katz for speaking with us today. Let's begin by understanding why you chose to conduct research into this topic.

Dr. Patricia Katz:

Well, thank you for having me and asking me to talk to you today. I have always been interested in issues of how lifestyle factors like sleep and physical activity affect people's disease course and the way that they can take care of their disease themselves. Because I think a lot of people would prefer to be able to do some things themselves for their health. And so, that led me to study sleep. That plus knowing the relationship between sleep and some inflammatory disorders that exist in the general population.

RALN:

All right. Would you give us an overview of the study? For example, source of data, the number of participants?

Dr. Patricia Katz:

The data came from a longitudinal observational cohort that includes people with all types of rheumatic and autoimmune conditions, and a large portion of them do have rheumatoid arthritis. So, data are from a longitudinal observational cohort of a large group of people who have all types of rheumatic conditions, a large portion of them have rheumatoid arthritis. And so, I chose to start with this group because of the numbers and also because of the known associations or the known reports from people with RA that sleep is a problem for them. Forward is something that's open to all types of people with rheumatic conditions, people can enroll themselves if they want to, and participants get interviews or fill out questionnaires every 6 months. And in one of those 6-month periods, we included some specific questions about sleep quality and also questions to try to identify whether people had symptoms of restless leg syndrome or obstructive sleep apnea or whether they had been formally diagnosed with either one of those conditions. So, this group is made up of a little over 4,000 people with RA.

RALN:

Okay. So, what did you find out about sleep disorders among patients with RA? And you mentioned restless leg syndrome. How common are conditions such as sleep apnea and restless leg syndrome?

Dr. Patricia Katz:

In the general population, they're not that common. For some, the prevalence of obstructive sleep apnea is somewhere in the general population around 4%, and among older people, age 60 to 65, in women it's about 8% and in men it's about 15%. Restless leg syndrome has a population estimate of about 15%. We found considerably higher prevalence of both of those conditions in RA. We found that 20% of the cohort had either been diagnosed with obstructive sleep apnea or was at risk based on their symptoms, so that's again compared to... Since this is primarily women in the sample, it's compared to about 8% in the general population. And we found that 30% had either been diagnosed with restless leg syndrome or had symptoms. And again, that's about twice as high as the prevalence in the population.

RALN:

From your research, from the results, it's pretty clear that pain could be associated with shorter periods of sleep. But how does RA disease activity relate to other conditions such as sleep apnea or restless leg syndrome?

Dr. Patricia Katz:

That's a good question. Restless leg syndrome, it's a little easier to understand because if people have pain, they might have difficulty sleeping. But restless leg syndrome is a specific condition, it's not just pain alone that would keep you awake, is these prickly painful feelings in your leg that you feel like you need to move. One of the factors that's associated with that is iron deficiency or anemia, and there is a higher prevalence of anemia in people with RA, so that's one issue. In terms of disease activity, I don't think it's clear whether there are inflammatory pathways that would be common between the sleep disorders and disease activity. So it may be that what we saw in terms of disease activity is a proxy for pain, it may be a proxy for something else, we really don't know. But I think it's intriguing and certainly given the effect of sleep problems like obstructive sleep apnea or restless legs, the effect that those can have on health in general, I think this is certainly something that requires more attention.

RALN:

Okay. Are there any contraindications among patients with RA for medications to treat these conditions? What I mean is, are there any specific risks of drug-drug interactions?

Dr. Patricia Katz:

So for obstructive sleep apnea there, the treatment is not a drug treatment. The most common treatment for obstructive sleep apnea is CPAP, Continuous Positive Air Pressure, so it's the mask that you put over your face. And a lot of people find those uncomfortable, and so there are some other things that are coming onto the market, but that's the most common. So no drug issues there. For restless leg syndrome, I believe that the first line treatment would probably be iron supplementation. And again, that's something that someone should talk to their rheumatologist about, but at the same time, I don't, that I know of, and I'm not a rheumatologist, I don't know of any drug-drug interactions. If the iron supplementation doesn't help, then there are other pathways to follow, which would require conversations with physicians.

RALN:

And could sleep apnea among these patients be related to interstitial lung disease, which is not uncommon among patients with RA?

Dr. Patricia Katz:

To the best of my knowledge, obstructive sleep apnea and interstitial lung disease are not related. The risk factors in general for obstructive sleep apnea are being overweight or obese, particularly if there's fat around the neck area because the reason people have sleep apnea is that your tongue or the tissues in your throat when you're sleeping collapse and block the airway. Other risk factors are hypertension, which is often present in people with RA, so that's something to consider. Men are more likely to have obstructive sleep apnea, and then age is also a risk factor. So, the older one gets the more likelihood that that's the case.

RALN:

That's interesting. Last question. Patients with rheumatic diseases often report consistent and troublesome fatigue. Could these high levels of reported sleep disruption be the cause or one of the causes of this condition?

Dr. Patricia Katz:

Yes. I think they could contribute. Clearly, if someone's not getting good sleep, they're going to feel more fatigued. Inadequate sleep is also associated with lower pain thresholds, and so someone might be more sensitive to pain if they're not sleeping well. And I should say, that these are 2 diagnosable sleep conditions. A lot of people have poor sleep and it's not because of obstructive sleep apnea or restless legs. And so, that's something that we are continuing to work on here, is to try to look at some of those other associations. But clearly, pain and fatigue could have a direct association.

RALN:

Right, right, right. Okay. Thank you for joining us today, Dr. Katz.

Dr. Patricia Katz:

Sure.

RALN:

Once again, that was Dr. Patricia Katz, Professor of Medicine and Health Policy at University of California, San Francisco, speaking to us about sleep disorders among patients with rheumatoid arthritis.

Dr. Patricia Katz:

Well, thank you, Priyam.