Saudi Journal of Kidney Diseases and Transplantation

: 2013  |  Volume : 24  |  Issue : 4  |  Page : 714--718

Sleep quality assessment using polysomnography in children on regular hemodialysis

Ahmed M El-Refaey1, Riad M ElSayed2, Amr Sarhan1, Ashraf Bakr1, Ayman Hammad1, Atef Elmougy1, Ahmed Y Aboelyazeed3,  
1 Pediatric Nephrology Unit, Mansoura University Children`s Hospital, Mansoura, Egypt
2 Pediatric Neurology Unit, Pediatric Department, Mansoura, Egypt
3 Community Medicine Department, Mansoura, Egypt

Correspondence Address:
Riad M ElSayed
Pediatric Neurology Unit, Mansoura University, Mansoura


Studies examining sleep patterns in children on hemodialysis (HD) are lacking. This cross-sectional, control-matched group study was performed to assess the sleep quality in children on HD. The assessment was made using a subjective sleep assessment and sleep questionnaire and objective analysis was made using full night polysomnography. A total of 25 children with end-stage renal disease (ESRD) on HD were compared with 15 age- and sex-matched controls. The average age of the cases was 14 ± 4 years, 52% were males and the mean body mass index was 20 ± 3.8 kg/m². The average duration on dialysis was 2.6 ± 2 years. Analysis of subjective data revealed markedly affected sleep quality in HD patients, as evidenced by excessive day time sleepiness (P <0.005), night awakening (P <0.005), difficult morning arousal (P <0.005) and limb pains (P <0.005). Objective analysis showed differences in sleep architecture, less slow wave sleep in HD children, similar rapid eye movement and non-rapid eye movement, more sleep disordered breathing (P <0.0001) and more periodic limb movement disorders (P <0.0001). Our study suggests that children on regular HD have markedly affected objective as well as subjective quality of sleep.

How to cite this article:
El-Refaey AM, ElSayed RM, Sarhan A, Bakr A, Hammad A, Elmougy A, Aboelyazeed AY. Sleep quality assessment using polysomnography in children on regular hemodialysis.Saudi J Kidney Dis Transpl 2013;24:714-718

How to cite this URL:
El-Refaey AM, ElSayed RM, Sarhan A, Bakr A, Hammad A, Elmougy A, Aboelyazeed AY. Sleep quality assessment using polysomnography in children on regular hemodialysis. Saudi J Kidney Dis Transpl [serial online] 2013 [cited 2020 Jul 7 ];24:714-718
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Full Text


Sleep disorders are common in adult dialysis patients with a prevalence of 50-80%. [1],[2],[3] Common disturbances include sleep-disordered breathing (SDB), restless leg syndrome (RLS) and periodic limb movements (PLMs). Signs and symptoms of these disorders include snoring and apnea and uncomfortable sensations in the legs. Studies that objectively monitor sleep using polysomnography (PSG) have suggested shorter sleep times, fragmented sleep and disturbed sleep architecture in HD patients. These disorders lead to insufficient or poor-quality sleep due either to sleep disruption, difficulties with sleep onset or sleep maintenance. More importantly, insufficient or poor quality sleep can lead to day time dysfunction, including excessive day time sleepiness, mood problems, impaired work performance and increased accidents. [4] To date, studies assessing sleep in pediatric dialysis patients are lacking. Therefore, this study was conducted to describe sleep disturbances in pediatric dialysis patients.

 Subjects and Methods


The current study was conducted on 25 children undergoing regular thrice-weekly HD in the Pediatric Nephrology Unit, Mansoura University Children's Hospital (MUCH). Measurements were made during the period from January 2009 to November 2009. Subjects included children of both sexes, with age ranging between 8 and 18 years who were on regular thrice-weekly HD. The exclusion criteria included patients with craniofacial malformation, genetic syndromes and advanced liver, cardiac or pulmonary diseases. Consent was taken from children and their parents to participate in the study. Fifteen age- and sex-matched healthy children were studied as controls.



Overnight PSG was performed on all HD patients and controls at the sleep laboratory of the Pediatric Neurology Unit in MUCH. PSG sleep recording included the measurement of four channel electroencephalogram (EEG) (C3, C4, 01, 02), electro-occulography (EOG) of right and left ocular movements (ROC, LOC), chin and leg surface electromyogram, chest movements, oro-nasal airflow, snoring, 12-lead electrocardiogram, pulse oximetry and body position channel.

Scoring of polysomnography

Data processing and scoring were made following identical procedures and were completed by trained scoring staff blinded to the clinical characteristics of the patients. Sleep stages were scored according to the guidelines developed by Rechtschaffen and Kales. [5] Arousals were identified according to the American Sleep Disorders Association criteria. [6] Apnea was defined as complete or almost complete cessation of breathing, with duration greater than 10 s. Hypopnea was defined as 30-50% reduction of airflow. Arousal was defined as finding 3 s of wake EEG. SDB was considered when the apnea-hypopnea index was more than five per hour of sleep. Periodic limb movements disorder (PLMD) was considered when the PLM index exceeded five per hour of sleep. [7]

Subjective sleep quality

Sleep symptoms were assessed using a validated pediatric sleep questionnaire, [8] which fulfilled the following points: Delayed sleep onset, night time awakening, difficulty to get back to sleep, difficult arousal in the morning, day time sleepiness, snoring and limb pains. We also studied the sleep room characters. We attempted to find correlations between the subjective and the objective findings.

 Statistical Analysis

Demographic and PSG data are expressed as mean ± SD, and the statistical significance between the groups was tested using a 2-sample t-test. Subjective data obtained by the sleep questionnaire are expressed in number of patients and percentage; statistical significance between the groups was tested by using the x 2 test.


Demographic data of the HD and control groups are listed in [Table 1]. The mean age was 14 ± 4 years, 52% were males and the mean body mass index (BMI) was 20 ± 3.8 kg/m². The two groups were matched for age, sex and BMI. The mean arterial blood pressure was significantly higher in the HD group (P = 0.05). The average duration on HD was 2.6 ± 2 years on regular thrice-weekly sessions.{Table 1}

Differences in the objective sleep parameters in the study samples are listed in [Table 2]. Overnight PSG showed similar sleep efficacy between the patients and the control group, with similar sleep latency, similar rapid eye movement sleep and non-rapid eye movement sleep times. There was a significantly less slow wave sleep value in the HD group (P <0.005). There were higher values of arousal index (P <0.005), respiratory disturbance index (RDI) and PLMD in the HD group (P <0.001) than in the controls. There were no differences in the heart rate or oxygen saturation between the two groups.{Table 2}

Differences in subjective data obtained by the sleep questionnaire in the study groups are listed in [Table 3]. There was a significantly high prevalence of day time symptoms in the HD children, which included excessive day time sleepiness (x 2 test, P <0.005), limb pains (x 2 test, P <0.005) and difficult morning arousals (x 2 test, P <0.005). Also, there were more night time symptoms in HD children, including night time awakening (x 2 test, P <0.005). No significant differences were observed in the prevalence of snoring and room sharing during night and day time naps. There was a significantly higher need for hypnotic medicines in the HD group (x 2 test, P <0.005).{Table 3}


Our study showed subjective and objective evidences of disturbed sleep quality in children on HD compared with the control group. This was confirmed by disturbed sleep architecture in the HD group noticed on PSG. Our dialysis center is specialized in pediatric HD and children are recruited from different locations in Egypt. Thus, our data represents different areas of Egypt.

The impairment of sleep quality in children undergoing HD will possibly affect their overall quality of life. There are few studies assessing sleep quality in children on HD, none which used PSG. One study used telephone or clinic interview, and concluded that sleep disturbances are common in HD children. [9] Unruh et al [3] studied 46 adult HD patients with a mean age of 62.7 ± 10.1 years, using home PSG and a sleep questionnaire and compared their results with matched controls from the sleep heart study. They found that patients undergoing thrice-weekly HD have markedly impaired subjective and objective sleep quality. They also found a poor correlation between subjective and objective findings. In our study, the data obtained from PSG confirmed disturbed sleep in children with more sensitivity to detect measured sleep parameters, especially PLMD, RDI and sleep staging. In a recent study, Barmar et al [10] used wrist actigraphy to assess sleep in 87 adult participants; 36 patients had chronic kidney disease (CKD), with a mean age of 51.3 ± 15.2 years, and 51 other patients were on HD, with a mean age of 54 ± 12.9 years. They found that patients on HD had more disturbed sleep, as evidenced by data obtained by actigraphy; less total sleep (P <0.05), less sleep efficiency (P <0.05) and fragmentation index (P <0.05). However, this study lacked a normal control group. In another study conducted by Iliescu et al, [11] sleep quality was measured using the Pittsburgh Sleep Quality Index in 120 prevalent adult CKD patients. The authors found that 53% of the patients suffered poor sleep. This study also had the limitation of lacking a normal control group.

Studies on the adult population have shown that short and fragmented sleep has been associated with day time symptoms, decreased psychomotor vigilance, poor driving performances, diminished memory, increased risk of cardiovascular diseases and premature risk. [12],[13]

In conclusion, the results of our study suggest that disturbed sleep quality is common in children on regular HD, and this can be assessed by using subjective methods like a self-reported sleep questionnaire and, in certain cases, needs to be confirmed by PSG. Polysomnographic studies are especially needed to assess the prevalence of sleep-disordered breathing and PLMD.


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