Megan Brooks

June 05, 2013

BALTIMORE, Maryland — Sleep disorders, particularly insomnia and sleep-disordered breathing (SDB), are common in patients with chronic kidney disease, new research confirms.

High rates of sleep disorders in this patient population "suggest an unmet need for the assessment and treatment of sleep disorders," the researchers say.

Sleep problems are an "overlooked issue in this patient group. However, overlooking sleep problems is not unique to this population," Jacob Williams, graduate student, Department of Clinical and Health Psychology, University of Florida, Gainesville, told Medscape Medical News.

The findings were presented here at SLEEP 2013: Associated Professional Sleep Societies 27th Annual Meeting.

Look Beyond Fatigue, Mood

In this study, Williams and colleagues assessed sleep disorders and clinical correlates among 44 patients with different stages of chronic kidney disease (30% with moderate to severe kidney impairment) recruited from transplant surgery and nephrology clinics at the University of Florida. Their median age was 53 years and 59% were women. All of them completed health surveys, 1 night of ambulatory polysomnography, and 2 weeks of sleep diaries.

The researchers found that one third of the sample (33%) had symptoms of SDB (apnea-hypopnea index [AHI] > 5). Among those with SDB, average AHI was 17.8. In addition, 53% of the sample met criteria for significant insomnia and 24% had both insomnia and SDB.

"We've known for a long time that sleep disorders are more common in kidney disease patients than in the general population," Charles Atwood, MD, associate director of the University of Pittsburgh Medical Center's Sleep Medicine Center in Pennsylvania, who wasn't involved in the study, told Medscape Medical News.

"A lot of studies in the past focused on the dialysis population. It seems like this group focused on people with milder degrees of kidney disease and basically found that they also have sleep disorders and I'm not surprised by that," he added.

Williams and colleagues also found that higher AHI scores were significantly related to body mass index (BMI), more napping, and less caffeine consumption. AHI scores were not significantly related to fatigue or mood in this sample, which is "somewhat surprising," Williams said, and suggests that these symptoms may not be as meaningful in identifying SDB in this particular population.

"Fatigue is one of the most common symptoms among end-stage renal disease regardless of the effects of sleep. The ubiquity of fatigue symptoms is likely what makes this symptom a relatively ineffective way to determine whether individuals are experiencing SDB," Williams speculated.

"Instead, looking at the individuals BMI, a common risk factor for SDB, and their behaviors, such napping and caffeine consumption, may be more useful in determining if further evaluation for SDB is warranted," he advised.

"We really don't understand what it is about kidney failure that causes people not to sleep well," Dr. Atwood said. "In general, kidney failure makes people feel fatigued and how much of that is due to them not sleeping well versus other issues is probably not known, it's probably a combination."

"There is likely an opportunity to improve patients' sleep by having patients change daily behaviors that are maintaining their sleeping problems," Williams added. "There is a growing body of support for cognitive-behavioral therapy (CBT) for insomnia as an evidence-based treatment for insomnia comorbid with a number of medical conditions, including chronic pain, breast cancer, fibromyalgia, and among other adults in general with variety of medical conditions," he noted.

The authors and Dr. Atwood have disclosed no relevant financial relationships.

SLEEP 2013: Associated Professional Sleep Societies 27th Annual Meeting. Abstract 0808.


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