Association of sleep-disordered breathing with cognitive dysfunction in CKD stages 4-5

Cognitive Impairment and Brain Atrophy in Patients with Chronic Kidney Disease

In Japan, the aging of the population is rapidly accelerating, with an increase in patients with chronic kidney disease (CKD) and those undergoing dialysis. As a result, the number of individuals with cognitive impairment (CI) is rising, and addressing this issue has become an urgent problem. A notable feature of dementia in CKD patients is the high frequency of vascular dementia, making its prevention through the management of classical risk factors such as hypertension, diabetes mellitus, dyslipidemia, smoking, etc., associated with atherosclerosis and arteriosclerosis. Other effective measures, including the use of renin-angiotensin system inhibitors, addressing anemia, exercise therapy, and lifestyle improvements, have been reported. The incidence and progression of CI may also be influenced by the type of kidney replacement therapy, with reports suggesting that long-duration dialysis, low-temperature hemodialysis, peritoneal dialysis, and kidney transplantation can have a preferable effect on the preservation of cognitive function. In conclusion, patients with CKD are at a higher risk of developing CI, with brain atrophy being a contributing factor. Despite the identification of various preventive measures, the evidence substantiating their efficacy remains limited across all studies. Future expectations lie in large-scale randomized controlled trials.

Cognitive disorders in patients with chronic kidney disease: Approaches to prevention and treatment

BACKGROUND

Cognitive impairment is common in patients with chronic kidney disease (CKD), and early intervention may prevent the progression of this condition.

METHODS

Here, we review interventions for the complications of CKD (anemia, secondary hyperparathyroidism, metabolic acidosis, harmful effects of dialysis, the accumulation of uremic toxins) and for prevention of vascular events, interventions that may potentially be protective against cognitive impairment. Furthermore, we discuss nonpharmacological and pharmacological methods to prevent cognitive impairment and/or minimize the latter's impact on CKD patients' daily lives.

RESULTS

A particular attention on kidney function assessment is suggested during work-up for cognitive impairment. Different approaches are promising to reduce cognitive burden in patients with CKD but the availabe dedicated data are scarce.

CONCLUSIONS

There is a need for studies assessing the effect of interventions on the cognitive function of patients with CKD.

Sleep duration and cognitive function among older adults with chronic kidney disease: results from the National Health and Nutrition Examination Survey (2011-2014)

BACKGROUND

Short and long sleep durations are associated with cognitive dysfunction. Given the increased prevalence of sleep abnormalities in the chronic kidney disease (CKD) population, we tested whether the association between sleep duration and cognitive function differed between older adults with and without CKD.

METHODS

This was a study of 3215 older adults (age ≥60 years) enrolled in the National Health and Nutrition Examination Survey (2011-14) evaluating sleep duration, cognitive function (immediate recall, delayed recall, verbal fluency, executive function and processing speed and global cognition) and kidney function. We quantified the association between sleep duration and cognitive function using linear regression and tested whether the associations differed among those with CKD and without using a Wald test for interaction.

RESULTS

Among 3215 participants, 13.3% reported 2-5 hours of sleep/day, 75.2% reported 6-8 hours, and 11.5% reported ≥9 hours. Persons with CKD were more likely to sleep ≥9 hours [odds ratio 1.73 (95% confidence interval 1.22-2.46)]. Among participants with CKD, those with a sleep duration ≥9 hours demonstrated worse global cognitive function (P for interaction = .01), immediate recall (P for interaction = .01) and verbal fluency (P for interaction = .004) than those with a sleep duration of 6-8 h; no differences were observed for participants with CKD who slept 2-5 hours. Among participants without CKD, sleep was not associated with any measures of cognitive function.

CONCLUSIONS

Longer sleep duration is associated with worse cognitive function only among persons with CKD, and global cognition, delayed recall and verbal fluency are particularly affected. Studies should identify interventions to improve sleep patterns and quality in this population.

Association Between Sleep Disorders and Cognitive Impairment in Middle Age and Older Adult Hemodialysis Patients: A Cross-Sectional Study

Objective: The aims of the current study were to (1) explore the features of overall poor sleep and specific sleep disorders in Chinese middle age and older adult hemodialysis patients; (2) examine the association between sleep disorders and cognitive impairment (CI) in middle age and older patients undergoing hemodialysis in China.

Methods: Data of patients undergoing maintenance hemodialysis were collected from the prospective cohort study of CI in Chinese patients undergoing hemodialysis (Registered in Clinical Trials.gov, ID: NCT03251573). We included 613 patients (mean age = 63.7; SD = 7.8) in this study. We assessed sleep conditions using the Pittsburgh Sleep Quality Index (PSQI) questionnaire and cognitive function by the Chinese Beijing version of the Montreal Cognitive Assessment (MoCA-BJ) scale. Then the association between sleep disorders and CI was evaluated using multivariate logistic regression analysis.

Results: The prevalence of sleep disorders in this group of 613 hemodialysis patients was 77.0%. Patients with CI were more inclined to have sleep disorders in specific aspects of sleep latency, habitual sleep efficiency, sleep disturbances, and daytime dysfunction (p < 0.05). In multivariate logistic regression analyses, every 1-point increase in global PSQI score was associated with a 1.2-fold increased risk of CI (adjusted OR = 1.201; 95%CI = 1.123–1.284, p < 0.001). For each specific PSQI, every 1-point increase in sleep disturbances score was associated with a 2.6-fold increased risk of CI (adjusted OR = 2.624; 95%CI = 1.891–3.640, p < 0.001), and every 1-point increase in daytime dysfunction score was associated with a 3.7-fold increased risk of CI (adjusted OR = 3.709; 95%CI = 2.653–5.184, p < 0.001), whereas every 1-point increase in sleep duration score was associated with a decreased risk of CI (adjusted OR = 0.600; 95%CI = 0.434–0.830, p = 0.002).

Conclusion: Poor sleep quality especially sleep disturbances, daytime dysfunction, and long sleep duration are associated with CI in middle age and older adult hemodialysis patients. Thus, the early detection of sleep disorders may help identify patients with cognitive impairment among hemodialysis individuals.

Clinical Trial Registration: [Clinical Trials.gov], identifier [NCT03251573]

Cognitive disorders in patients with chronic kidney disease: specificities of clinical assessment

Neurocognitive disorders are frequent among chronic kidney disease (CKD) patients. Identifying and characterizing cognitive impairment (CI) can help to assess the ability of adherence to CKD risk reduction strategy, identify potentially reversible causes of cognitive decline, modify pharmacotherapy, educate the patient and caregiver and provide appropriate patient and caregiver support. Numerous factors are associated with the development and progression of CI in CKD patients and various conditions can influence the results of cognitive assessment in these patients. Here we review clinical warning signs that should lead to cognitive screening; conditions frequent in CKD at risk to interfere with cognitive testing or performance, including specificities of cognitive assessment in dialysis patients or after kidney transplantation; and available tests for screening and observed cognitive patterns in CKD patients.

Is kidney a new organ target in patients with obstructive sleep apnea? Research priorities in a rapidly evolving field

The bidirectional relationship between sleep disordered breathing and chronic kidney disease (CKD) has recently gained a lot of interest. Several lines of evidence suggest the high prevalence of coexistent obstructive sleep apnea (OSA) in patients with CKD and end-stage renal disease (ESRD). In addition, OSA seems to result in loss of kidney function in some patients, especially in those with cardio-metabolic comorbidities. Treatment of CKD/ESRD and OSA can alter the natural history of each other; still better phenotyping with selection of appropriate treatment approaches is urgently needed. The aim of this narrative review is to provide an update of recent studies on epidemiological associations, pathophysiological interactions, and management of patients with OSA and CKD or ESRD.

A Narrative Review of Management Strategies for Common Symptoms in Advanced CKD

Patients with advanced chronic kidney disease (CKD) experience multiple bothersome symptoms, undermining their quality of life (QOL). With growing attention to the importance of symptom management in advanced CKD, the evidence regarding symptoms is increasing. In this review, we briefly summarize the current evidence of effective pharmacologic and nonpharmacologic interventions to improve symptoms and QOL in patients with advanced CKD, including those on dialysis. We focused on symptoms that are commonly experienced by patients, such as pain, fatigue, sleep disturbances, itching, nausea and vomiting, cognitive impairment, and anxiety and depression. We noted that research in symptom science focused on improving symptom management in CKD is still very limited. In addition to the lack of clinical practice guidelines to address those common symptoms, the major gaps in the current literature include the evidence regarding mechanistic pathways to inform the development of effective symptom management for CKD populations, the evidence to confirm effective pharmacologic interventions in other populations for CKD populations, and research on how to incorporate effective symptom management approaches into clinical care. Although improving mortality remains as an important area in the kidney community, there is an urgent need to focus on improving symptom management to improve QOL in advanced CKD.

Quality of life of obstructive sleep apnoea patients receiving continuous positive airway pressure treatment: A systematic review and meta-analysis

BACKGROUND

Previous studies have shown conflicting results on the effect of continuous positive airway pressure (CPAP) on quality of life (QoL) in obstructive sleep apnoea (OSA) patients.

OBJECTIVES

To evaluate the effect of CPAP on QoL in OSA patients compared to sham CPAP, placebo pills, and conservative treatment.

METHODS

Studies were identified via Web of Knowledge, PubMed, PsychInfo, CINAHL, EMBASE, OpenGrey, and the Cochrane Library. Subgroup analyses and sensitivity analyses were conducted to assess the robustness of the findings.

RESULTS

Meta-analysis of 13 randomised controlled trials showed no significant differences in overall and psychological QoL comparing values of CPAP treated patients with controls; however, physical QoL improved. CPAP significantly affected the overall QoL in studies with controls receiving sham CPAP, parallel design, low risk of bias, and mild OSA patients.

CONCLUSION

CPAP treatment may help to improve physical symptoms of OSA, whereas impaired psychological QoL still cannot be alleviated.

Sleep Disorders and Cognitive Impairment in Peritoneal Dialysis: A Multicenter Prospective Cohort Study

BACKGROUND

Patients with chronic kidney disease experience a high burden of sleep disorders, and there are associations between sleep disorders and cognitive impairment.

OBJECTIVES

Based on our previous cross-sectional survey on cognitive impairment in peritoneal dialysis, we further explored the relationship between sleep disorders and cognitive impairment, and predictors for declining cognitive function.

METHOD

We conducted a multicenter prospective cohort study enrolling 458 clinically stable patients on peritoneal dialysis who were then followed up for 2 years.Demographic data, comorbidities, depression, and biochemistry data were collected at baseline. Sleep disorders including insomnia, restless legs syndrome, sleep apnea syndrome, excessive daytime sleepiness, possible narcolepsy, sleep walking and nightmares, and possible rapid eye movement behavior disorders were assessed using a panel of specific sleep questionnaires at baseline and in a second survey. Global cognitive function was measured at baseline and in a second survey, using the Modified Mini-Mental State Examination. Specific cognitive domains were evaluated using Trail-Making Test Forms A and B for executive function, and subtests of the Battery for the Assessment of Neuropsychological Status were used to asses immediate and delayed memory, visuospatial skills, and language ability.

RESULTS

Sleep disorders were common among peritoneal dialysis patients. The prevalence of cognitive impairment evaluated by the Modified Mini-Mental State Examination (3MS) increased from 19.8 to 23.9%. Possible narcolepsy was associated with decreased Modified Mini-Mental State Examination scores at baseline. During follow-up, sleepwalking and nightmares were associated with higher risks of declined delayed memory in the longitudinal study.

CONCLUSIONS

Possible narcolepsy was associated with general cognitive dysfunction, and sleep walking and nightmares were risk factors for impaired delayed memory.

Sleep-disordered breathing and Alzheimer's disease: A nationwide cohort study

Sleep-disordered breathing (SDB) is common and can lead to significant cognitive decline, such as Alzheimer's disease (AD). Therefore, the present study was conducted to investigate whether SDB is associated with AD onset. This study used the nationwide health check-up cohort data between 2002 and 2015. The study population comprised individuals who were diagnosed with SDB and those without SDB who were matched by using propensity score. The matched cohort was followed up until the onset of AD, death, or end of 2015. A multivariate Cox proportional hazard model was used in the analysis. There were 727 (16.7%) patients in the SDB group between 2002 and 2005 and 3635 subjects (83.3%) in the propensity score-matched non-SDB group. After adjusting for the possible confounding variables, patients with SDB were almost 1.58 times more likely to develop AD than those without SDB (hazard ratio [HR] = 1.575, 95% confidence interval [CI] = 1.013-2.448). The present study showed that SDB was associated with an onset of AD. The findings of this study highlight the importance of the interventions to raise awareness of SDB and the need for the government's support to reduce the barrier in accessing appropriate SDB treatment.

White matter structural differences in OSA patients experiencing residual daytime sleepiness with high CPAP use: a non-Gaussian diffusion MRI study

OBJECTIVES

To investigate factors associated with residual sleepiness in patients who were highly adherent to continuous positive airway pressure (CPAP). Nocturnal inactivity, comorbidities, concomitant medications, and, in particular, white matter (WM) differences using diffusion magnetic resonance imaging (MRI) were explored using a continuous-time random-walk (CTRW) model.

METHODS

Twenty-seven male patients (30-55 years of age) with obstructive sleep apnea (OSA) received CPAP as the only treatment (CPAP ≥ 6 h/night) for at least 30 days. Based on the Psychomotor Vigilance Task (PVT) results, participants were divided into a non-sleepy group (lapses ≤ 5; n = 18) and a sleepy group (lapses > 5; n = 9). Mean nocturnal inactivity (sleep proxy) was measured using actigraphy for one week. Diffusion-weighted imaging (DWI) with high b-values, as well as diffusion tensor imaging (DTI), was performed on a 3 T MRI scanner. The DWI dataset was analyzed using the CTRW model that yielded three parameters: temporal diffusion heterogeneity α, spatial diffusion heterogeneity β, and an anomalous diffusion coefficient D_m. The differences in α, β, and D_m between the two groups were investigated by a whole-brain analysis using tract-based spatial statistics (TBSS), followed by a regional analysis on individual fiber tracts using a standard parcellation template. Results from the CTRW model were compared with those obtained from DTI. The three CTRW parameters were also correlated with the clinical assessment scores, Epworth Sleepiness Scale (ESS), PVT lapses, and PVT mean reaction time (MRT) in specific fiber tracts.

RESULTS

There were no differences between groups in mean sleep duration, comorbidities, and the number or type of medications, including alerting and sedating medications. In the whole-brain DWI analysis, the sleepy group showed higher α (17.27% of the WM voxels) and D_m (17.14%) when compared to the non-sleepy group (P < 0.05), whereas no significant difference in β was observed. In the regional fiber analysis, the sleepy and non-sleepy groups showed significant differences in α, β, or their combinations in a total of 12 fiber tracts; whereas similar differences were not observed in DTI parameters, when age was used as a covariate. Additionally, moderate to strong correlations between the CTRW parameters (α, β, or D_m) and the sleepiness assessment scores (ESS, PVT lapses, or PVT MRT) were observed in specific fiber tracts (|R| = 0.448-0.654, P = 0.0003-0.019).

CONCLUSIONS

The observed differences in the CTRW parameters between the two groups indicate that WM alterations can be a possible mechanism to explain reversible versus residual sleepiness observed in OSA patients with identical high level of CPAP use. The moderate to strong correlations between the CTRW parameters and the clinical scores suggest the possibility of developing objective and quantitative imaging markers to complement clinical assessment of OSA patients.

Psychological distress in patients with obstructive sleep apnoea: The role of hostility and coping self-efficacy

We aimed to assess whether hostility and coping self-efficacy are associated with psychological distress in obstructive sleep apnoea patients. Furthermore, we examined whether coping self-efficacy mediates the association between hostility and psychological distress. We included 150 obstructive sleep apnoea patients (Apnoea-Hypopnoea Index ⩾5; 68% male; mean age: 48.9 ± 9.5 years). Regression models showed that hostility and poor coping self-efficacy were strongly associated with psychological distress in obstructive sleep apnoea patients. All assessed coping self-efficacy dimensions mediated the association between hostility and psychological distress. Coping self-efficacy for stopping unpleasant emotions and thoughts showed the strongest association with a lower level of psychological distress.

A holistic approach to factors affecting depression in haemodialysis patients

Depression in dialysis populations is affected by co-morbid diseases, such as cardiovascular disease, diabetes, and immune dysfunction, and it also includes high suicide risk and frequent hospitalizations. Depressive disorders have a close association with malnutrition and chronic inflammation, as well as with cognitive impairment. Impaired cognitive function may be manifested as low adherence to dialysis treatment, leading to malnutrition. Additionally, chronic pain and low quality of sleep lead to high rates of depressive symptoms in haemodialysis patients, while an untreated depression can cause sleep disturbances and increased mortality risk. Depression can also lead to sexual dysfunction and non-adherence, while unemployment can cause depressive disorders, due to patients' feelings of being a financial burden on their family. The present review provides a holistic approach to the factors affecting depression in haemodialysis, offering significant knowledge to renal professionals.

Effects of 12 months of continuous positive airway pressure therapy on cognitive function, sleep, mood, and health-related quality of life in a peritoneal dialysis patient with obstructive sleep apnea

This report describes the case of a hypertensive 51-year-old male with a 3-year history of peritoneal dialysis. We followed the patient through his diagnosis of severe obstructive sleep apnea (OSA) and treatment with continuous positive airway pressure (CPAP). Therapeutic use of CPAP led to the improvement of not only sleep-related problems, but also cognitive function and quality of life. To our knowledge, this is the first paper describing the benefits of long-term CPAP treatment in an OSA patient undergoing dialysis. This case report emphasizes the need for the proactive diagnosis and treatment of OSA in end-stage renal disease patients to improve patient-centered healthcare.

Screening of Cognitive Impairment in the Dialysis Population: A Scoping Review

BACKGROUND

Cognitive impairment in end-stage kidney disease patients on dialysis is increasingly common. This study aimed to review the practice of screening and to evaluate the evidence on cognitive impairment prevalence in this population.

METHODS

This scoping review of studies summarises the evidence on cognitive impairment in dialysis populations. The search included the Medline, CINAHL, Embase, PsycINFO, PubMed, and Cochrane Library databases for English-language articles published between 2000 and 2015. A total of 46 articles were reviewed.

RESULTS

The studies were of prospective observational design, with the majority conducted in the haemodialysis population. The reported prevalence of cognitive impairment ranged from 6.6 to 51%. Three screening tools were consistently used.

CONCLUSION

While cognitive impairment is recognised in the dialysis population, there is paucity of screening data. The design of prospective comparisons ideally includes established screening instruments, particularly the Montreal Cognitive Assessment, to determine the optimal results for this population. Translation of established screening tools to increase the inclusion of people from other cultural and language groups is required. Regular screening can enhance the timing to introduce home-based care support and advance care planning discussions.

Sleep apnea prevalence in chronic kidney disease - association with total body water and symptoms

Background

Sleep apnea is common and associated with poor outcome in severe chronic kidney disease, but validated screening tools are not available. Our objectives were to determine the prevalence of sleep apnea in this population, to assess the validity of screening for sleep apnea using an ApneaLink device and to investigate the relationship of sleep apnea to; symptoms, spirometry and body water.

Methods

Patients with glomerular filtration rate ≤30 mL/min/1.73 m², whether or not they were receiving haemodialysis, were eligible for enrolment. Participants completed symptom questionnaires, performed an ApneaLink recording and had total body water measured using bioimpedance. This was followed by a multi-channel polysomnography recording which is the gold-standard diagnostic test for sleep apnea.

Results

Fifty-seven participants were enrolled and had baseline data collected, of whom only 2 did not have sleep apnea. An apnea hypopnea index ≥30/h was found in 66% of haemodialysis and 54% of non-dialysis participants. A central apnea index ≥5/h was present in 11 patients, with only one dialysis patient having predominantly central sleep apnea. ApneaLink underestimated sleep apnea severity, particularly in the non-dialysis group. Neither total body water corrected for body size, spirometry, subjective sleepiness nor overall symptom scores were associated with sleep apnea severity.

Conclusions

This study demonstrates a very high prevalence of severe sleep apnea in patients with chronic kidney disease. Sleep apnea severity was not associated with quality of life or sleepiness scores and was unrelated to total body water corrected for body size. Routine identification of sleep apnea with polysomnography rather than screening is more appropriate in this group due to the high prevalence.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0544-3) contains supplementary material, which is available to authorized users.

The Burden of Cognitive Impairment in Patients With End-Stage Renal Disease and Impact on Dialysis Modality Choice

Introduction

Kidney disease is associated with significant cognitive dysfunction. Subjective reports of cognitive ability have not been studied extensively in chronic kidney disease. We investigated the association between objective and subjective cognitive functions in predialysis patients and their association with self-care dialysis modality choice.

Methods

Cross-sectional data from the Barriers to Successful Implementation of Care in Home Haemodialysis study were used for the study of cognition in 220 predialysis patients. The data were used to ascertain the demographics, clinical, laboratory, and neuropsychometric variables. The latter includes Trail Making Tests (TMT) parts A and B, Modified Mini Mental State Examination, and metacognition questionnaire for subjective assessment of one's cognitive ability. The outcome variable was fully assisted and self-care dialysis modality choice.

Results

Within the study cohort, 90 patients chose fully assisted hemodialysis and 114 patients chose self-care dialysis. The median Modified Mini Mental State Examination, TMT part A, and TMT part B scores were greater for the assisted versus the self-care group. Metamemory was not significantly different between groups, but the metaconcentration score was significantly worse in the group choosing assisted dialysis. Higher (i.e., better) metaconcentration scores were significantly associated with the self-care modality choice in the univariate and hierarchical regression analyses. Adjusted and unadjusted analyses showed a significant association between perceived concentration and TMT part B scores (P < 0.01). With every 1.6-minute increase in TMT part B score, there was a 1-unit reduction in metaconcentration score, and the latter was associated with 20% lower odds of choosing self-care dialysis over a fully assisted dialysis modality.

Discussion

Patients' self-perception of cognitive ability is a significant predictor of self-care dialysis modality choice. Subjective report of "metaconcentration" is also strongly associated with poorer outcome on the TMT part B.

Sleep-Disordered Breathing in 2 Pediatric Patients on Peritoneal Dialysis

Sleep-disordered breathing (SDB) is prevalent in children with chronic kidney disease (CKD), and has the potential to worsen vascular and neuro-cognitive health and quality of life. We present 2 children with CKD who experience central sleep apnea and nocturnal hypoventilation and discuss the possible underlying mechanisms in relation to CKD and dialysis.

Sleep-Disordered Breathing in Patients with Polycystic Liver and Kidney Disease Referred for Transcatheter Arterial Embolization

BACKGROUND AND OBJECTIVES

Sleep-disordered breathing (SDB) is prevalent among patients with CKD, but its prevalence among patients with symptomatic autosomal dominant polycystic kidney disease (ADPKD) and its association with total liver and kidney volume remain unclear.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study examined the association between height-adjusted total liver and kidney volume (htTLKV) and SDB in a cross-sectional study of 304 adult patients with symptomatic ADPKD who were hospitalized at Toranomon Hospital for transcatheter arterial embolization and who underwent pulse oximetry between April 2008 and November 2013. SDB was defined as having a 3% oxygen desaturation index of ≥15 events per hour of sleep. Logistic regression was performed with sex-specific quartiles of htTLKV as the main predictor, using patient data and comorbidities as covariates.

RESULTS

Overall (54.6% women, mean age 56.2±9.4 years, 83.5% on hemodialysis), 177 of 304 patients (58.2%) had SDB. SDB was strongly associated with htTLKV quartiles, demonstrating that odds ratios (ORs) and 95% confidence intervals (95% CIs) for SDB were 1.63 (0.76 to 3.48), 2.35 (1.09 to 5.06), and 4.61 (1.98 to 10.7) for htTLKV quartiles 2-4 (P for trend, P=0.003), respectively. Older age (OR, 1.81 per 10 years; 95% CI, 1.29 to 2.55), male sex (OR, 3.87; 95% CI, 1.96 to 7.66), receiving hemodialysis (OR, 3.46; 95% CI, 1.62 to 12.1), and higher body mass index (≥25 kg/m(2)) (OR, 3.03; 95% CI, 1.08 to 8.52) were also associated with SDB.

CONCLUSIONS

In this highly selected population of patients with symptomatic ADPKD referred for transcatheter arterial embolization, SDB was highly prevalent and independently associated with higher htTLKV.

Cognitive and physical function in chronic kidney disease

PURPOSE OF REVIEW

Both cognitive and physical function are commonly impaired in individuals with chronic kidney disease (CKD), resulting in important impacts on their quality of life and overall health. This review summarizes the burden of cognitive and physical impairment in CKD, focusing on recent research that highlights a possible unifying microvascular cause among these shared comorbid conditions.

RECENT FINDINGS

Multiple small studies have been published recently evaluating cognitive and physical functioning in people with CKD. These studies overall demonstrate a high burden of comorbid conditions in people with CKD, including microvascular disease, that may result in cognitive impairment. Additionally, studies demonstrate that physical function is substantially worse than expected in individuals with CKD, that decreased physical activity is associated with worse outcomes, that frailty is very common and associated with an increased risk of death, and that structured exercise programs have small but tangible short-term effects on markers of physical performance.

SUMMARY

Impaired cognitive function and physical performance are important factors impacting the lives of people with CKD. Further research is necessary to better treat these important comorbid conditions in people with CKD.

The effect of Benson's relaxation technique on the quality of sleep of Iranian hemodialysis patients: a randomized trial

OBJECTIVE

This study was performed to evaluate the effectiveness of Benson's relaxation technique in the quality of sleep of hemodialysis patients.

DESIGN

It was a randomized controlled trial with a pre-post-test design. A total of 86 hemodialysis patients referring to hemodialysis units were assigned to either the intervention (receiving Benson's relaxation technique) or the control group (routine care) through block randomization.

SETTING

The study was performed in two hemodialysis units affiliated to Shiraz University of Medical Sciences, Shiraz, Iran.

INTERVENTION

The patients in the intervention group listened to the audiotape of Benson's relaxation technique twice a day each time for twenty minutes for eight weeks.

MAIN OUTCOME MEASURES

The global score of Pittsburgh Sleep Quality Index (PSQI) as well as its components was computed in both the intervention and the control group before and at the 8th week of the intervention.

RESULTS

The results of ANCOVA indicated significant differences between the two groups regarding the scores of Pittsburgh Sleep Quality Index subscales, such as sleep disturbance, daytime dysfunction, the use of sleep medication, and subjective sleep quality and as well as its global scores at the 8th week of the intervention (p<0.05).

CONCLUSIONS

This study highlighted the importance of Benson's relaxation technique in improvement of the sleep quality of the patients on hemodialysis. Thus, educational sessions are recommended to be planned on this cost effective and easy to use relaxation technique in order to improve hemodialysis patients' sleep quality. Further studies are needed to assess the effectiveness of this technique in other groups of patients.