Habitual sleep and kidney function in chronic kidney disease: the Chronic Renal Insufficiency Cohort study

Disrupting circadian control of autophagy induces podocyte injury and proteinuria

The circadian clock influences a wide range of biological process and controls numerous aspects of physiology to adapt to the daily environmental changes caused by Earth's rotation. The kidney clock plays an important role in maintaining tubular function, but its effect on podocytes remains unclear. Here, we found that podocytes expressed CLOCK proteins, and that 2666 glomerular gene transcripts (13.4%), including autophagy related genes, had 24-hour circadian rhythms. Deletion of Clock in podocytes resulted in 1666 gene transcripts with the loss of circadian rhythm including autophagy genes. Podocyte-specific Clock knockout mice at age three and eight months showed deficient autophagy, loss of podocytes and increased albuminuria. Chromatin immunoprecipitation (ChIP) sequence analysis indicated autophagy related genes were targets of CLOCK in podocytes. ChIP-PCR further confirmed Clock binding to the promoter regions of Becn1 and Atg12, two autophagy related genes. Furthermore, the association of CLOCK regulated autophagy with chronic sleep fragmentation and diabetic kidney disease was analyzed. Chronic sleep fragmentation resulted in the loss of glomerular Clock rhythm, inhibition of podocyte autophagy, and proteinuria. Rhythmic oscillations of Clock also disappeared in high glucose treated podocytes and in glomeruli from diabetic mice. Finally, circadian differences in podocyte autophagy were also abolished in diabetic mice. Deletion Clock in podocytes aggravated podocyte injury and proteinuria in diabetic mice. Thus, our findings demonstrate that clock-dependent regulation of autophagy may be essential for podocyte survival. Hence. loss of circadian controlled autophagy may play an important role in podocyte injury and proteinuria.

The association between circadian syndrome and chronic kidney disease in an aging population: a 4-year follow-up study

Introduction

Circadian syndrome (CircS) is proposed as a novel risk cluster based on reduced sleep duration, abdominal obesity, depression, hypertension, dyslipidemia and hyperglycemia. However, the association between CircS and chronic kidney disease (CKD) remains unclear. To investigate the cross-sectional and longitudinal association between CircS and CKD, this study was performed.

Methods

A national prospective cohort (China Health and Retirement Longitudinal Study, CHARLS) was used in this study. To define CKD, the estimated glomerular filtration rate (eGFR) was calculated based on the 2012 CKD-EPI creatinine-cystatin C equation. Participants with eGFR <60 mL.min-1/1.73/m2 were diagnosed with CKD. Multivariate binary logistic regression was used to assess the cross-sectional association between CircS and CKD. Subgroup and interactive analyses were performed to determine the interactive effects of covariates. In the sensitivity analysis, the obese population was excluded and another method for calculating the eGFR was used to verify the robustness of previous findings. In addition, participants without CKD at baseline were followed up for four years to investigate the longitudinal relationship between CircS and CKD.

Results

A total of 6355 participants were included in this study. In the full model, CircS was positively associated with CKD (OR = 1.28, 95% CI = 1.04-1.59, P < 0.05). As per one increase of CircS components, there was a 1.11-fold (95% CI = 1.04-1.18, P < 0.05) risk of prevalent CKD in the full model. A significant interactive effect of hyperuricemia in the CircS-CKD association (P for interaction < 0.01) was observed. Sensitivity analyses excluding the obese population and using the 2009 CKD-EPI creatinine equation to diagnose CKD supported the positive correlation between CircS and CKD. In the 2011-2015 follow-up cohort, the CircS group had a 2.18-fold risk of incident CKD (95% CI = 1.33-3.58, P < 0.01) in the full model. The OR was 1.29 (95% CI = 1.10-1.51, P < 0.001) with per one increase of CircS components.

Conclusion

CircS is a risk factor for CKD and may serve as a predictor of CKD for early identification and intervention.

New insights into the mechanisms of diabetic kidney disease: Role of circadian rhythm and Bmal1

It is common for diabetic kidney disease (DKD) to be complicated by abnormal blood glucose, blood lipids, and blood pressure rhythms. Thus, it is essential to examine diagnostic and treatment plans from the perspective of circadian disruption. This brief review discusses the clinical relevance of circadian rhythms in DKD and how the core clock gene encoding brain and muscle arnt-like protein 1 (BMAL1) functions owing to the importance of circadian rhythm disruption processes, including the excretion of urinary protein and irregular blood pressure, which occur in DKD. Exploring Bmal1 and its potential mechanisms and signaling pathways in DKD following contact with Sirt1 and NF-κB is novel and important. Finally, potential pharmacological and behavioral intervention strategies for DKD circadian rhythm disturbance are outlined. This review aids in unveiling novel, potential molecular targets for DKD based on circadian rhythms.

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.

Associations between sleep characteristics, chronotype and body mass index among Chinese college freshmen

Research indicates that sleep problem is a behavioral risk factor of obesity. However, few research have applied a multi-dimensional approach to investigate the relationship between sleep health and adiposity. Therefore, the current study aimed to examine the associations of sleep characteristics (duration, quality) and chronotype with overweight/obesity as measured by body mass index. Data were obtained from 2014 college students from the Dali University in the Yunnan province of China in the year 2021. Sleep characteristics and chronotype were measured using self-reported questionnaires. The presence of overweight/obesity was assessed by anthropometric measurements. Multiple logistic regression models and restricted cubic spline hazard models were established to examine associations between sleep characteristics, chronotype and adiposity. After adjusting for demographic characteristics and other obesity-related behavioral risk factors, evening type was positively associated with overweight/obesity, and an L-shaped dose-effect relationship was observed between chronotype scores and the presence of overweight/obesity. However, sleep duration and quality were not associated with the presence of overweight/obesity in the logistic regression models and restrictive cubic splines models. This study indicated that Chinese college students who had the evening chronotype were more likely to be affected by overweight/obesity. Chronotype as an important dimension of sleep health should be incorporated in obesity intervention programs.

Association of Self-Reported Nighttime Sleep Duration with Chronic Kidney Disease: China Health and Retirement Longitudinal Study

INTRODUCTION

The cohort study aimed to assess the association of nighttime sleep duration and the change in nighttime sleep duration with chronic kidney disease (CKD) and whether the association between nighttime sleep duration and CKD differed by daytime napping.

METHODS

This study included 11,677 individuals from the China Health and Retirement Longitudinal Study (CHARLS) and used data from the 2011 baseline survey and four follow-up waves. Nighttime sleep duration was divided into three groups: short (<7 h per night), optimal (7-9 h), and long nighttime sleep duration (>9 h). Daytime napping was divided into two groups: no nap and with a nap. We used Cox proportional hazards model to examine the effect of nighttime sleep duration at baseline and change in nighttime sleep duration on incident CKD and a joint effect of nighttime sleep duration and nap time on onset CKD.

RESULTS

With a follow-up of 7 years, the incidence of CKD among those with short, optimal, and long nighttime sleep duration was 9.89, 6.75, and 9.05 per 1,000 person-years, respectively. Compared to individuals with optimal nighttime sleep duration, short nighttime sleepers had a 44% higher risk of onset CKD (hazard ratio [HR]: 1.44, 95% confidence interval [CI]: 1.21-1.72). Compared to participants with persistent optimal nighttime sleep duration, those with persistent short or long nighttime sleep duration had an increased risk of incident CKD (HR: 1.44, 95% CI: 1.15-1.80). We found a lower incidence of CKD in participants with short nighttime sleep duration and a nap (HR: 0.74, 95% CI: 0.60-0.93), compared to those with short nighttime sleep duration and no nap.

CONCLUSION

Short nighttime sleep duration and persistent long or short nighttime sleep duration were associated with a higher risk of onset CKD. Keeping persistent optimal nighttime sleep duration may help reduce CKD risk later in life. Daytime napping may be protective against CKD incidence.

Association between sleep parameters and chronic kidney disease: findings from iranian ravansar cohort study

INTRODUCTION

The relationship between sleep duration and chronic kidney disease (CKD) has received relatively little attention in the Kurdish community. Considering the ethnic diversity of Iran and the importance of the Kurdish community, the present study investigated the association between sleep parameters and CKD among a large sample of Iranian-Kurds.

METHODS

This cross-sectional study was conducted among 9,766 participants (M_age: 47.33, SD = 8.27, 51% female) from the Ravansar Non Communicable Disease (RaNCD) cohort study database. Logistic regression analyses were applied to examine the association between sleep parameters and CKD.

RESULTS

Results showed that prevalence of CKD was detected in 1,058 (10.83%) individuals. Time to fall asleep (p = 0.012) and dozing off during the day (p = 0.041) were significantly higher in the non-CKD group compared to the CKD group. Daytime napping and dozing off during the day in females with CKD were significantly more than males with CKD. A long sleep duration (> 8 h/day) was associated with 28% (95% CI: 1.05, 1.57) higher odds of CKD compared to normal sleep duration (7 h/d), after adjusting for confounding factors. Participants who experienced leg restlessness had a 32% higher probability of developing CKD than those who did not experience leg restlessness (95% CI: 1.03, 1.69).

CONCLUSION

Results suggest that sleep duration and leg restlessness may be associated with an increased likelihood of CKD. Consequently, regulating sleep parameters may play a role in improving sleep and preventing CKD.

Toward Precision Medicine: Circadian Rhythm of Blood Pressure and Chronotherapy for Hypertension - 2021 NHLBI Workshop Report

Healthy individuals exhibit blood pressure variation over a 24-hour period with higher blood pressure during wakefulness and lower blood pressure during sleep. Loss or disruption of the blood pressure circadian rhythm has been linked to adverse health outcomes, for example, cardiovascular disease, dementia, and chronic kidney disease. However, the current diagnostic and therapeutic approaches lack sufficient attention to the circadian rhythmicity of blood pressure. Sleep patterns, hormone release, eating habits, digestion, body temperature, renal and cardiovascular function, and other important host functions as well as gut microbiota exhibit circadian rhythms, and influence circadian rhythms of blood pressure. Potential benefits of nonpharmacologic interventions such as meal timing, and pharmacologic chronotherapeutic interventions, such as the bedtime administration of antihypertensive medications, have recently been suggested in some studies. However, the mechanisms underlying circadian rhythm-mediated blood pressure regulation and the efficacy of chronotherapy in hypertension remain unclear. This review summarizes the results of the National Heart, Lung, and Blood Institute workshop convened on October 27 to 29, 2021 to assess knowledge gaps and research opportunities in the study of circadian rhythm of blood pressure and chronotherapy for hypertension.

Factors associated with poor sleep quality in patients with pre-dialysis chronic kidney disease: A systematic review

AIMS

To determine factors associated with poor sleep quality among patients with pre-dialysis chronic kidney disease.

DESIGN

This is a systematic review study guided by Preferred Reporting Items for Systematic Reviews and Meta-Analyses statements and checklist.

DATA SOURCES

Empirical evidence was sought in major electronic databases, including Embase, MEDLINE, CINAHL and Airiti library from March to September 2022.

REVIEW METHODS

Studies investigating factors associated with poor sleep quality among adult patients with chronic kidney disease were included. Study participants who received renal replacement therapy and had sleep disorders and serious illnesses such as cancer were excluded. Of the 526 studies that resulted from the search after removing duplicate articles, 20 studies were assessed for quality by using Joanna Briggs Institute and Newcastle-Ottawa Scale by two doctorial prepared nursing scientists.

RESULTS

A total of 20 studies were included in this review. The prevalence of poor sleep quality in these studies ranged from 11% to 97.5%. Demographics (older age and female), physiological conditions (higher body mass index, higher hip circumferences, higher systolic blood pressure, poor cardiovascular function, dyspnoea, pain, cramps, itchiness or moderate to extreme pruritus, lower fasting plasma glucose, electrolyte imbalance, higher total cholesterol and gastrointestinal symptoms), depression, smoking, arousal-related and cognitive arousal behaviours were associated with poor sleep quality.

CONCLUSION

Poor sleep quality was prevalent and influenced kidney function, increased mortality as well as decreased quality of life in patients with pre-dialysis chronic kidney disease. This review synthesizes factors associated with poor sleep quality. Managing these factors can mitigate and prevent poor sleep quality.

IMPACT

Healthcare providers, especially nurses, can assess the risk factors of poor sleep quality and reinforce patients' self-management. Future research should elucidate the assessment and management of risk factors and transfer these into widespread use in the routine care of patients with chronic kidney disease.

Comparison of Diagnostic Value for Chronic Kidney Disease between 640-Slice Computed Tomography Kidney Scan and Conventional Computed Tomography Scan

Objective

To explore the diagnostic value for chronic kidney disease (CKD) between 640-slice computed tomography (CT) kidney scan and conventional CT scan.

Methods

A total of 120 CKD patients who received kidney plain scan plus enhanced examination in the CT room of the Medical Imaging Department of our hospital from June 2019 to September 2019 were selected and randomly divided into the experimental group (n = 60) and the control group (n = 60). Patients in the control group received the conventional CT plain scan and enhanced scan, and for patients in the experimental group, CT plain scan was performed first, the range of 640-slice CT dynamic volume scan was determined, and after bolus injection of contrast agent, dynamic volume scan was performed for scanning in the cortical phase, myeloid phase, and secretory phase. The imaging quality and effective scanning dose were compared between the two modalities, and the relationship between CT values obtained from 640-slice CT scan and conventional CT scan and the renal impairment was analyzed.

Results

Compared with the control group, the image quality of 640-slice CT scan conducted in the experimental group was significantly better (P < 0.05); the effective radiation doses of the experimental group and the control group were, respectively, (1.89 ± 0.32) mSv and (3.26 ± 0.47) mSv, indicating that the dose was significantly lower in the experimental group than in the control group (t = 18.664, P < 0.001), and the correlation analysis showed that the relationship between the sum of CT values in the cortical phase of both kidneys and kidney injury in the experimental group was r = 0.835, P < 0.001.

Conclusion

Both 640-slice CT kidney scan and conventional CT scan can be used in the diagnosis of CKD. 640-slice CT has a lower radiation dose, better image quality, and higher application value.

Rapamycin ameliorates chronic intermittent hypoxia and sleep deprivation-induced renal damage via the mammalian target of rapamycin (mTOR)/NOD-like receptor protein 3 (NLRP3) signaling pathway

Rapamycin inhibits the activation of NOD-like receptor protein 3 (NLRP3) by regulating the mammalian target of rapamycin (mTOR) to treat obstructive sleep apnea-related renal injury. Sleep deprivation (SD) and chronic intermittent hypoxia (CIH) mouse models were used to assess the effects of autophagy in vivo. Compared with the control, SD, and CIH groups, the SD+CIH group had lower body weight and higher levels of blood urea nitrogen (BUN), creatinine, and urinary albumin (U-Alb) (P < 0.05); renal injury and oxidative damage occurred in the SD+CIH group, the kidney cell nucleus ruptured, and morphological structure of the cells was unclear in the SD+CIH group. The SD+CIH group demonstrated increased apoptosis compared with the control, SD, and CIH groups using Western blot analysis. Compared to the control, SD, and CIH groups, the SD+CIH group showed a higher degree of microtubule-associated protein light chain 3\ staining. Compared to the SD+CIH group, BUN, creatinine, and U-Alb levels decreased, and apoptosis increased in the SD+CIH+rapamycin group, and the structure of the kidney after rapamycin treatment was well preserved. The mTOR expression was increased in the kidneys of the SD+CIH group. The NLRP3, Gasdermin D (GMDSD), interleukin (IL)-18, IL-1β, and cleaved-caspase-1 protein levels were higher in the SD+CIH group than the SD+CIH+rapamycin group, and the NLRP3, GMDSD, IL-18, IL-1β, and cleaved-caspase-1 mRNA levels were higher in the SD+CIH group than the SD+CIH+rapamycin group. Following rapamycin treatment, pyroptosis was suppressed. Rapamycin ameliorates renal damage by inhibiting the mTOR/NLRP3 signaling pathway.

Sleeping, Smoking, and Kidney Diseases: Evidence From the NHANES 2017-2018

Study Objectives: Smoking and sleep are modifiable factors associated with the chronic kidney diseases. However, the interaction of smoking and sleep on the renal function are still unclear. Therefore, we aimed to evaluate the interactive impacts of smoking and sleep on the renal function. Methods: Data were obtained from the National Health and Nutrition Examination Survey. The study population were categorized into nine subgroups by smoking (smoking every day, sometimes, and non-smokers recently) and sleep duration (short duration ≤ 6 h, normal duration 6-9 h, and longer duration ≥ 9 h on the weekdays). Results: The study group with a short sleep duration had significantly higher serum cotinine and hydrocotinine levels compared with the other two sleep groups. After adjusting the demographic characteristics (age, race, body mass index, and marital status), sleep quality (snoring or breathing cessation), and comorbidities (diabetes mellitus, hypertension, high cholesterol, anemia, congestive heart failure, coronary heart disease, and stroke), non-smokers with short or long sleep duration had significant lower estimated glomerular filtration rate (eGFR) levels than the study group who smoked every day and slept ≤ 6 h. The effects of sleep duration on eGFR levels varied with smoking status. For the study group smoking every day, eGFR levels increased as sleep duration decreased, whereas for the study group smoking sometimes, eGFR levels increased as sleep duration increased. The U-shaped effects of eGFR levels were observed among non-smokers whose normal sleep duration was associated with better eGFR levels. Normal sleep duration was an important protective factor of the renal function for non-smokers than smokers. Conclusions: The effects of sleep duration on eGFR levels varied with smoking status. Normal sleep duration was a protective factor and more crucial for non-smokers than for smokers.

The association of nighttime sleep duration and quality with chronic kidney disease in middle-aged and older Chinese: a cohort study

OBJECTIVE

This cohort study aimed to assess the associations between sleep duration and quality with the risk of incident chronic kidney disease (CKD) in middle-aged and older Chinese.

METHODS

We used the 2011 and 2015 surveys of the China Health and Retirement Longitudinal Study (CHARLS). Nighttime sleep duration was categorized into five groups: ≤4, (4-6], (6-8], (8-10], and >10 h/night. Sleep quality was assessed by restless days in the past week (<1, 1-2, 3-4, and 5-7 days/week). Multivariate logistic regression was used to assess the association between sleep duration and quality with incident CKD.

RESULTS

A total of 11,339 participants free of CKD at baseline were included in this study. After four years follow-up, the incidence of CKD was 7.8%. There was a "U-shaped" association between sleep duration and risk of CKD. Compared to 6-8 h of nighttime sleep duration, those who slept ≤4 h/night (RR: 1.639, 95% CI: 1.287-2.087) or >10 h/night (RR: 2.342, 95% CI: 1.007-5.451) had increased risk of developing CKD after adjustment for confounders. Participants with 5-7 restless days per week had significantly increased risk of CKD (adjusted RR: 1.686, 95% CI: 1.352-2.102), compared to those who rarely or never had a restless sleep.

CONCLUSIONS

Extreme nighttime sleep duration and poor sleep quality were associated with increased risk of CKD in middle-aged and older Chinese. Obtaining an optimal nighttime sleep duration and better sleep quality might reduce the risk of CKD.

Patient experiences of sleep in dialysis: systematic review of qualitative studies

RATIONALE AND OBJECTIVE

Sleep problems affect more than half of patients receiving dialysis and are associated with increased risk of mortality, cardiovascular events, depression and impaired functioning and quality of life. Symptoms such as fatigue and exhaustion may be attributed to sleep problems or sleep disorders, as well as the burden of kidney disease and treatment. This study aims to describe the patient perspectives on the reasons, impact and management of sleep problems in dialysis.

STUDY DESIGN

Systematic review and thematic synthesis of qualitative studies that report patient experience and perspectives on sleep in dialysis.

SETTING AND POPULATION

Patients receiving dialysis.

SEARCH STRATEGY AND SOURCES

MEDLINE, Embase, PsycINFO, CINAHL, reference lists and PhD dissertations were searched from inception to August 2019.

DATA EXTRACTION

All text from the results/conclusion of the primary studies.

ANALYTICAL APPROACH

Thematic synthesis.

RESULTS

We included 48 studies involving 1156 participants from 16 countries. We identified six themes: dominating demands of treatment (with subthemes of: demanding and relentless schedule, regret for wasted time); scheduling and control (managing sleep routines, napping and nocturnal sleep disruption, meditative aids); disruptions due to dialysis (unsettled sleep, hypervigilance and worry); symptoms depriving sleep (difficulty falling asleep, constant waking); overwhelmed and without choice (futility of sleep, uncontrollable exhaustion, restlessness is irrepressible); and as a coping mechanism (avoiding anxiety, alleviating symptoms, combating boredom).

LIMITATIONS

Most studies were conducted in high-income, English-speaking countries.

CONCLUSION

The treatment and symptom burden of dialysis disrupts and deprives patients of sleep, which leads to overwhelming and uncontrollable exhaustion. Better management of symptoms and effective strategies to manage sleep routines may improve sleep quality for better overall health in patients receiving dialysis.

Multiple, objectively measured sleep dimensions including hypoxic burden and chronic kidney disease: findings from the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Poor sleep may contribute to chronic kidney disease (CKD) through several pathways, including hypoxia-induced systemic and intraglomerular pressure, inflammation, oxidative stress and endothelial dysfunction. However, few studies have investigated the association between multiple objectively measured sleep dimensions and CKD.

METHODS

We investigated the cross-sectional association between sleep dimensions and CKD among 1895 Multi-Ethnic Study of Atherosclerosis Sleep Ancillary Study participants who completed in-home polysomnography, wrist actigraphy and a sleep questionnaire. Using Poisson regression models with robust variance, we estimated separate prevalence ratios (PR) and 95% CIs for moderate-to-severe CKD (glomerular filtration rate <60 mL/min/1.73 m² or albuminuria >30 mg/g) among participants according to multiple sleep dimensions, including very short (≤5 hours) sleep, Apnoea-Hypopnoea Index and sleep apnoea-specific hypoxic burden (SASHB) (total area under the respiratory event-related desaturation curve divided by total sleep duration, %min/hour)). Regression models were adjusted for sociodemographic characteristics, health behaviours and clinical characteristics.

RESULTS

Of the 1895 participants, mean age was 68.2±9.1 years, 54% were women, 37% were white, 28% black, 24% Hispanic/Latino and 11% Asian. Several sleep metrics were associated with higher adjusted PR of moderate-to-severe CKD: very short versus recommended sleep duration (PR=1.40, 95% CI 1.06 to 1.83); SASHB (Box-Cox transformed SASHB: PR=1.06, 95% CI 1.02 to 1.12); and for participants in the highest quintile of SASHB plus sleep apnoea: PR=1.28, 95% CI 1.01 to 1.63.

CONCLUSIONS

Sleep apnoea associated hypoxia and very short sleep, likely representing independent biological mechanisms, were associated with a higher moderate-to-severe CKD prevalence, which highlights the potential role for novel interventions.

Effects of sleep apnea and kidney dysfunction on objective sleep quality in nondialyzed patients with chronic kidney disease: an ESADA study

STUDY OBJECTIVES

Patients with chronic kidney disease (CKD) often report poor sleep quality, but they commonly exhibit OSA. The aim of this study was to evaluate the influence of OSA severity and of estimated glomerular filtration rate impairment on objective sleep quality in nondialyzed patients with CKD, defined as an estimated glomerular filtration rate <60 mL/min/1.73m².

METHODS

Polysomnographic sleep characteristics were compared between patients with (n = 430) and without CKD (n = 6,639) in the European Sleep Apnea Database cohort. Comparisons were repeated in 375 patients with CKD and 375 control patients without CKD matched for sleep center, age, sex, and AHI, and in 310 matched CKD and non-CKD patients without psychiatric disturbances.

RESULTS

Among all patients with and without CKD, total sleep time was similar but sleep stage N1 (median 8.7% [IQR 4.8-18.0] vs 6.7% [3.6-12.7], respectively) and sleep stage R (12.6% [6.8-17.7] vs 14.2% [8.8-19.8], respectively) significantly differed (P < .0001). No difference in sleep characteristics was observed between matched patients either with or without psychiatric disturbances. After subdividing the matched patients according to AHI tertile (<25, ≥25 to <49, and ≥49 events/h) and estimated glomerular filtration rate (≥60, 45 to <60, <45 mL/min/1.73m²), we found a significant effect of AHI on sleep stages N2, N3, and R (P < .001), but there was no effect of CKD.

CONCLUSIONS

In nondialyzed patients with CKD, objective sleep quality is influenced similarly by AHI as in patients without CKD but is not affected by CKD severity. Previously reported poor sleep quality in CKD may partly result from the high prevalence of OSA in CKD.

Resistance training improves sleep quality, redox balance and inflammatory profile in maintenance hemodialysis patients: a randomized controlled trial

Patients in maintenance hemodialisys (HD) present sleep disorders, increased inflammation, unbalanced redox profiles, and elevated biomarkers representing endothelial dysfunction. Resistance training (RT) has shown to mitigate the loss of muscle mass, strength, improve inflammatory profiles, and endothelial function while decreasing oxidative stress for those in HD. However, the relation between those factors and sleep quality are inadequately described. The aim of this study was to verify the effects of 3 months of RT on sleep quality, redox balance, nitric oxide (NO) bioavailability, inflammation profile, and asymmetric dimethylarginine (ADMA) in patients undergoing HD. Our primary goal was to describe the role of RT on sleep quality. Our secondary goal was to evaluate the effect of RT on NO, metabolism markers, and inflammatory and redox profiles as potential mechanisms to explain RT-induced sleep quality changes. Fifty-five men undergoing maintenance hemodialysis were randomized into either a control (CTL, n = 25) and RT group (RTG; n = 30). Participants in the RT group demonstrated an improvement in sleep pattern, redox, inflammatory profiles, and biomarkers of endothelial function (NO₂^- and ADMA). This group also increased muscle strength (total workload in RT exercises of upper and lower limbs). These findings support that RT may improve the clinical status of HD patients by improving their sleep quality, oxidative and inflammatory parameters.

Medical Histories of Control Subjects Influence the Biomarker Potential of Plasma Aβ in Alzheimer's Disease: a Meta-analysis

Whether blood amyloid-β (Aβ) could be a peripheral biomarker of Alzheimer's disease (AD) remains in dispute. In the present study, we conducted a meta-analysis with 19 citations searched from Embase, PubMed, and the Cochrane Library database. Weighted mean difference (WMD) with 95% confidence intervals (CIs) was used to estimate the effect size. We firstly analyzed the plasma Aβ₄₀, Aβ₄₂, and Aβ₄₂/Aβ₄₀ ratio in AD and control group subjects. However, only a lower level of plasma Aβ₄₂ was figured out in AD group subjects with weak statistical significance (WMD 1.82; 95% CI 0.59, 3.06; P = 0.004; I² = 84%). We considered that the medical histories of control subjects could influence the biomarker ability of plasma Aβ. Therefore, subgroup analyses were then carried out based on a new recruiting criterion for control subjects, defining as no afflictions of any Aβ-related diseases. Surprisingly, AD group subjects showed a significant decrease in plasma Aβ₄₂/Aβ₄₀ ratio with low heterogeneity among studies (WMD 0.02; 95% CI 0.02, 0.02; P < 0.00001; I² = 0%). Moreover, not only the Aβ₄₂/Aβ₄₀ ratio but also Aβ₄₂ and Aβ₄₀ were indifferent between AD and pseudo-control subjects which might be afflicted with Aβ-related diseases. This meta-analysis demonstrated that medical histories of control subjects were interference factors impeding plasma Aβ to be a biomarker of AD.

Chronodisruption: A Poorly Recognized Feature of CKD

Multiple physiological variables change over time in a predictable and repetitive manner, guided by molecular clocks that respond to external and internal clues and are coordinated by a central clock. The kidney is the site of one of the most active peripheral clocks. Biological rhythms, of which the best known are circadian rhythms, are required for normal physiology of the kidneys and other organs. Chronodisruption refers to the chronic disruption of circadian rhythms leading to disease. While there is evidence that circadian rhythms may be altered in kidney disease and that altered circadian rhythms may accelerate chronic kidney disease (CKD) progression, there is no comprehensive review on chronodisruption and chronodisruptors in CKD and its manifestations. Indeed, the term chronodisruption has been rarely applied to CKD despite chronodisruptors being potential therapeutic targets in CKD patients. We now discuss evidence for chronodisruption in CKD and the impact of chronodisruption on CKD manifestations, identify potential chronodisruptors, some of them uremic toxins, and their therapeutic implications, and discuss current unanswered questions on this topic.

Self-reported sleep duration and daytime napping are associated with renal hyperfiltration and microalbuminuria in an apparently healthy Chinese population

Background

Sleep duration affects health in various ways. The objective of the present study was to investigate the relationships among sleep duration, daytime napping and kidney function in a middle-aged apparently healthy Chinese population.

Methods

According to self-reported total sleep and daytime napping durations, 33,850 participants who were 38–90 years old and recruited from eight regional centers were divided into subgroups. Height, weight, waist circumference, hip circumference, blood pressure, biochemical indexes, fasting blood glucose (FBG), postprandial blood glucose (PBG), HbA1c, creatinine and urinary albumin-creatinine ratio (UACR) were measured and recorded for each subject. Microalbuminuria was defined as UACR ≥30 mg/g, chronic kidney disease (CKD) was defined as eGFR <60 ml/min, and hyperfiltration was defined as eGFR ≥135 ml/min. Multiple logistic regression was applied to investigate the association between sleep and kidney function.

Results

Compared to sleeping for 7–8 h/day, the ORs for microalbuminuria for sleeping for >9 h/day, 8–9 h/day 6–7 h/day and <6 h/day were 1.343 (1.228–1.470, P<0.001), 1.223 (1.134–1.320, P<0.001), 1.130 (1.003–1.273, P = 0.045) and 1.140 (0.908–1.431, P = 0.259), respectively. The eGFR levels exhibited a U-shaped association with sleep duration among subjects with an eGFR ≥90 ml/min and an N-shaped association with sleep duration among subjects with an eGFR <90 ml/min. The OR for hyperfiltration for >9 h/day of sleep was 1.400 (1.123–1.745, P = 0.003) among participants with an eGFR ≥90 ml/min. Daytime napping had a negative effect on renal health. Compared to the absence of a napping habit, the ORs for microalbuminuria for 0–1 h/day, 1–1.5 h/day and >1.5 h/day of daytime napping were 1.552 (1.444–1.668, P<0.001), 1.301 (1.135–1.491, P<0.001) and 1.567 (1.353–1.814, P<0.001), respectively.

Conclusion

The association of total sleep duration with renal health outcomes is U-shaped. Daytime napping has a negative effect on renal health.

Snoring and incident chronic kidney disease: a community-based prospective cohort study

OBJECTIVES

Previous studies have shown that symptoms of sleep-disordered breathing are associated with metabolic derangements and vascular disease development. However, the relationship between snoring and renal function is not well investigated. The association between snoring and the development of incident chronic kidney disease (CKD) in subjects with normal renal function was evaluated.

DESIGN

Prospective cohort study.

SETTING

Ansung (rural community) and Ansan (urban community) cities.

PARTICIPANTS

Community-based cohort participants aged 40-69 years.

METHODS

A total of 9062 participants in the Ansung-Ansan cohort study were prospectively followed up from 2001 to 2014. The participants were classified into three groups: non-snorer, <1 day/week and ≥1 day/week. The main outcome was incident CKD, which was defined as an estimated glomerular filtration rate of <60 mL/min/1.73 m² during the follow-up period.

PRIMARY OUTCOME

Incident CKD.

RESULTS

The mean subject age was 52.0±8.9 years, and 4372 (48.2%) subjects were male. The non-snorer,<1 day/week and ≥1 day/week groups included 3493 (38.5%), 3749 (41.4%), and 1820 (20.1%) subjects, respectively. Metabolic syndrome was more prevalent in the snoring groups than in the non-snoring group. Snoring frequency showed a significant positive relationship with age, waist:hip ratio, fasting glucose, total cholesterol (Tchol) and low-density lipoprotein cholesterol. During a mean follow-up of 8.9 years, 764 (8.4%) subjects developed CKD. Cox proportional hazards model analysis revealed that the risk of CKD development was significantly higher in subjects who snored ≥1 day/week than in non-snorers, even after adjustments for confounding factors (HR 1.23, 95% CI 1.09 to 1.38, p<0.01).

CONCLUSION

Snoring may increase the risk of CKD development in subjects with normal renal function.

Circadian regulation of renal function

The kidneys regulate many vital functions that require precise control throughout the day. These functions, such as maintaining sodium balance or regulating arterial pressure, rely on an intrinsic clock mechanism that was commonly believed to be controlled by the central nervous system. Mounting evidence in recent years has unveiled previously underappreciated depth of influence by circadian rhythms and clock genes on renal function, at the molecular and physiological level, independent of other external factors. The impact of circadian rhythms in the kidney also affects individuals from a clinical standpoint, as the loss of rhythmic activity or clock gene expression have been documented in various cardiovascular diseases. Fortunately, the prognostic value of examining circadian rhythms may prove useful in determining the progression of a kidney-related disease, and chronotherapy is a clinical intervention that requires consideration of circadian and diurnal rhythms in the kidney. In this review, we discuss evidence of circadian regulation in the kidney from basic and clinical research in order to provide a foundation on which a great deal of future research is needed to expand our understanding of circadian relevant biology.

Longer time spent in bed attempting to sleep is associated with rapid renal function decline: the Dongfeng-Tongji cohort study

INTRODUCTION

Prospective evidence on the relation between time in bed and renal dysfunction remains limited. We aimed to investigate the association of time spent in bed attempting to sleep (TSBS) with renal function decline in a middle-aged and elderly Chinese population.

METHODS

About 16,733 eligible participants with a mean age of 62.3 years at baseline were included. Rapid renal function decline was defined as (baseline eGFR - revisit eGFR)/years of follow-up ≥5 mL/min per 1.73 m²/year. A total of 1738 study participants experienced rapid renal function decline after a median 4.6-year follow-up. Logistic regression models were used for multivariate analyses.

RESULTS

The adjusted odds ratio (OR) of rapid renal function decline was 1.18 (95% CI: 1.02, 1.37) for TSBS ≥9 h/night compared with TSBS 7 to <8 h/night. This association remained significant (OR = 1.19, 95% CI: 1.03, 1.38) after further adjustment for sleep quality, midday napping and usage of sleeping pills. Particularly, the association appeared to be prominent in individuals with diabetes.

CONCLUSIONS

Longer TSBS (≥9 h) was independently associated with an increased risk of rapid renal function decline. Our findings emphasized the importance to have optimal TSBS. Key messages Our study firstly investigated the association between time spent in bed attempting to sleep (TSBS) and renal dysfunction in Chinese adults. Compared with individuals TSBS 7 to <8 h, individuals with TSBS ≥9 h had 19% increased risk for rapid renal function decline after adjustment for multivariate confounders. The association appeared to be prominent in individuals with diabetes.