Poor Sleep Common in Chronic Kidney Disease

Poor Sleep Common in Chronic Kidney Disease

Nearly one in five pre-dialysis patients with chronic kidney disease (CKD) did not get the optimal amount of sleep, and this was associated with poorer quality-of-life outcomes, according to an observational study, reports Medpage Today.

Of the 1,910 participants, 11% reported not getting enough sleep (defined as 5 hours or less per night) and 7% said they slept too much (defined as 9 hours or more), said Kyu-Beck Lee, MD, of the Sungkyunkwan University School of Medicine in Seoul, Korea, and colleagues.

Patients who got the optimal 7 hours of sleep each night scored higher on the physical component of the Short-Form-36 Health Survey (an average 76 out of 100), compared with “under sleepers” (67/100) and “over sleepers” (62/100)(P <0.01 for trend), Lee’s team reported online in the Clinical Journal of the American Society of Nephrology.

Optimal sleepers also scored higher on the mental component of the survey (72/100) compared with short sleepers (64/100) and long sleepers (62/100), although this trend did not reach statistical significance, the researchers said.

After they adjusted for variables that included age, sex, smoking, alcohol consumption, physical activity, hypertension, cardiovascular disease, and diabetes, under sleepers were found to be significantly more likely to report lower physical quality of life (odds ratio 3.23; 95% CI 1.86-5.60) and mental quality of life (OR 2.37; 95% CI 1.43-3.94) compared with optimal sleepers. Over sleepers were also more likely to report lower physical (OR 2.80; 95% CI 1.55-5.03) and mental quality of life (OR 2.08; 05% CI 1.20-3.60), the study found.

Quality of Life and Sleep Duration

“Sleep duration had a U-shaped association with low HRQOL [health-related quality of life], and a 7-hour sleep duration showed the highest HRQOL,” Lee’s group wrote. “Adequate sleep is important to restore functional capacity and maintain homeostasis in the kidney. The influences of sleep on kidney disease are complex and little known.”

“In my opinion, this study is confirmatory of the importance of the appropriate sleep duration,” Joseph Vassalotti, MD, chief medical officer of the National Kidney Foundation, who was not involved with the study, told MedPage Today via email. “Clinicians who care for patients with CKD are aware of the importance of certain sleep symptoms and disorders such as nocturia, obstructive sleep apnea (OSA), and restless leg syndrome, as these are relevant to prostate disease, hypertension, and uremia respectively. That duration of sleep is associated with quality of life in CKD may be novel.

“Extremes of sleep duration outside of the 6 to 8 hours range should be assessed to determine if there is an underlying etiology, such as OSA, nocturia, medication side effects, pain, depression, restless leg syndrome, pruritus, or uremia,” Vassalotti advised. “Lifestyle modification plays an important role in sleep duration, particularly in those who have no clear identifiable cause.”

The researchers analyzed cross-sectional data on pre-dialysis patients from the Korean Cohort Study for Outcome in Patients with CKD (KNOW-CKD), a study designed to identify risk factors related to CKD and its outcomes. More than half of the patients (62%) were men, and mean age was 52. Mean estimated glomerular filtration rate (eGFR) was 53 ml/min per 1.73 m2, and the median 24-hour urine protein was 546 mg/d. One third of participants (33%) had diabetes, and 11% had cardiovascular disease.

Clinical measurements were taken at baseline, and study participants completed a sleep questionnaire in addition to the Short-Form-36 Health Survey. The investigators used multivariable logistic regression analysis to examine the relationship between self-reported sleep duration and health-related quality of life.

The study found that eGFR was significantly higher in the optimal sleepers (55 ml/min per 1.73 m2) versus the short sleepers (54 ml/min per 1.73 m2) and long sleepers (39 ml/min per 1.73 m2) (P<0.001 for trend). Mean 24-hour urine protein also differed significantly among the optimal sleepers (600 mg/d) compared with the under sleepers (383 mg/d) and over sleepers (852 mg/d) (P<0.01 for trend).

Sleep disorders, such as insomnia, restless leg syndrome, and sleep apnea, are prevalent in patients with Chronic Kidney Disease.

“Sleep duration has declined, and sleep problems have increased in current society,” Lee and colleagues wrote. “There is growing evidence that sleep is related to health outcomes.” Recent studies have suggested that insomnia is linked to a higher risk of developing and dying from cardiovascular disease. Short or long sleep duration has been associated with higher mortality risk, the team added.

“Sleep disorders, such as insomnia, restless leg syndrome, and sleep apnea, are prevalent in patients with CKD — in particular, those undergoing dialysis. However, few studies have attempted to characterize sleep duration in pre-dialysis CKD.”

Lack of sleep has been associated with neuroendocrine dysfunction, which can cause fatigue and lethargy in CKD, and too much sleep has been linked with sarcopenia, malnutrition, and depression, among other comorbidities, the researchers noted.

Limitations of the study, the team said, include the cross-sectional design, which cannot infer causality. In addition, the self-reported measures of sleep could have been inaccurate, and the single measure of sleep may not have captured the sustained effect of sleep problems on disease outcomes, they said. “Further studies are necessary to evaluate health outcomes by improving sleep duration in adults with CKD.”

Source: Sleep Review Magazine