Sleep disturbances as nontraditional risk factors for development and progression of CKD: review of the evidence

The association of sleep duration with the risk of chronic kidney disease: a systematic review and meta-analysis

Background and hypothesis

Published literature suggests that sleep duration and quality may be affected in adults with chronic kidney disease. However, the relationship between these two entities remains a matter of debate. The objective of this systematic review and meta-analysis is to assess the effect of sleep duration and quality on chronic kidney disease.

Methods

A systematic review of the Medline/PubMed, Embase, Cochrane Library, and CINAHL databases was conducted for articles pertaining to the association between sleep duration and quality on chronic kidney disease. The main outcome was the hazard/risk ratio of chronic kidney disease in patients of varying sleep durations and quality.

Results

In total, 42 studies (2 613 971 patients) with a mean age of 43.55 ± 14.01 years were included in the meta-analysis. Compared with a reference range of 7 to 8 hours of sleep, short sleep durations of ≤4 hours (RR 1.41, 95% CI: 1.16 to 1.71, P < 0.01), ≤5 hours (RR 1.46, 95% CI: 1.22 to 1.76, P < 0.01), ≤6 hours (RR 1.18, 95% CI: 1.09 to 1.29, P < 0.01), and ≤7 hours (RR 1.19, 95% CI: 1.12 to 1.28, P < 0.01) were significantly associated with an increased risk of incident chronic kidney disease. Long sleep durations of ≥8 hours (RR 1.15, 95% CI: 1.03 to 1.28, P < 0.01) and ≥9 hours (RR 1.46, 95% CI: 1.28 to 1.68, P < 0.01) were also significantly associated with an increased risk of incident chronic kidney disease. Meta-regression did not find any significant effect of age, gender, geographical region, and BMI and an association with sleep duration and risk of incident chronic kidney disease.

Conclusion

Both short and long sleep durations were significantly associated with a higher risk of chronic kidney disease. Interventions targeted toward achieving an optimal duration of sleep may reduce the risk of incident chronic kidney disease.

Impaired kidney function among young healthcare workers with long working hours and night work

OBJECTIVES

We aimed to evaluate the association between long working hours, night work, and estimated glomerular filtration rate (eGFR) among young healthcare workers.

METHODS

We conducted a retrospective cohort study among healthcare workers in a tertiary medical center in Taiwan from 2002 to 2021. Other than physicians, all hospital employees aged 20-65 years with documented yearly working hours and an annual blood test including creatinine were eligible. We excluded participants with eGFR <60 ml/min/1.73 m2 and proteinuria at enrollment to focus on early renal impairment. Total working hours, night working hours, and eGFR in each year were collected. We assessed the relationship of total working hours and night and non-night working hours with eGFR using the generalized linear mixed model, adjusting for demographic, comorbidities, and laboratory profiles.

RESULTS

The study included 10 677 participants with a mean age of 27.2 (standard deviation 7.1) years. The mean follow-up duration was 6.2 years. For every 10-hour increase in total weekly working hours, the eGFR decreased by 0.86 [95% confidence interval (CI) 0.61-1.11] ml/min/1.73 m2. For every 10-hour increase in weekly night working hours, the eGFR decreased by 0.25 (95% CI 0.07-0.42) ml/min/1.73 m2. In stratified analysis, the negative associations between total working hours and eGFR remained in the subgroups of individuals aged <40 years and those without hypertension or diabetes, with a P-value for interaction of <0.05.

CONCLUSIONS

Longer working hours and night work were associated with lower eGFR among healthcare workers.

Short or long sleep duration was associated with chronic kidney disease in a Chinese nationwide cohort study

OBJECTIVE

Sleep duration is an important factor influencing health outcomes. The association between sleep duration and kidney function remains elusive. This study aimed to explore the association between sleep duration and chronic kidney disease (CKD) amongst Chinese adults.

METHODS

We conducted a cross-sectional study based on the China Health and Nutrition Survey (CHNS) in the wave of 2009. Participants were divided into three groups: ≤ 6 h/day (short sleepers), 7-8 h/day (regular sleepers) and ≥ 9 h/day (long sleepers) according to self-reported sleep duration. CKD was defined as estimated glomerular filtration rate < 60 mL/min/1.73 m2.

RESULTS

A total of 8096 Chinese adults (45.9% men) with a mean age of 50.6 years were included in the study. Compared with regular sleepers, both short and long regular sleepers had a higher prevalence of CKD. A U-shaped relationship between sleep duration and CKD was displayed by restricted cubic spline curve (P-overall < 0.001, P-nonlinear < 0.001). Multivariate logistic regression models revealed that both short and long sleep duration were clinically associated with higher odds of CKD, after adjustments for covariates [adjusted odds ratio (OR) 1.25 and 1.30; 95% confidence interval (CI) 1.00-1.56 and 1.08-1.54, for short and long sleep duration, respectively]. In subgroup analyses, we found the association was still observed in participants without hypertension or diabetes mellitus.

CONCLUSION

Short or long sleep duration was associated with CKD in the general population.

Association of daytime napping with incidence of chronic kidney disease and end-stage kidney disease: A prospective observational study

BACKGROUND AND AIMS

Few studies have examined the relationship between daytime napping and risk of kidney diseases. We aimed to investigate the association of daytime napping with the incidence of chronic kidney disease (CKD) and end-stage kidney disease (ESKD). We also examined whether sleep duration modified the association of nap with CKD or ESKD.

METHODS

We recruited 460,571 European middle- to older-aged adults without prior CKD or ESKD between March 13, 2006, and October 1, 2010, in the UK Biobank. Sleep behavior data were obtained through questionnaires administered during recruitment. The analysis of the relationship between napping and the occurrence of CKD and ESKD utilized Cox proportional hazards regression models. The modification role of sleep duration on the effect of nap on CKD and ESKD was also examined.

RESULTS

After a mean follow-up of 11.1 (standard deviation 2.2) years, we observed 28,330 incident CKD cases and 927 ESKD cases. The daytime napping was associated with incident CKD (P for trend = .004). After fully adjusted, when compared with participants who did not take nap, those in sometimes and usually nap groups had higher risk of CKD. Nevertheless, the available evidence did not support a link between daytime napping and ESKD (P for trend = .06). Simultaneously, there was insufficient evidence suggesting that sleeping duration modified the association of daytime napping with incident CKD or ESKD.

CONCLUSION

Daytime napping was associated with an increased risk of CKD. However, the absence of conclusive evidence did not indicate a connection between daytime napping and ESKD.

Sleep Duration and Kidney Function - Does Weekend Sleep Matter?

Objective

Weekend sleep duration is linked to health issues, including mortality. However, how weekend sleep duration can impact chronic kidney disease (CKD) still needs to be understood. Therefore, we aimed to analyze how weekend sleep duration is associated with kidney function.

Methods

This is a cross-sectional study. Data were obtained from the 2017-2018 National Health and Nutrition Examination Survey. We included 5362 study participants and categorized them into nine subgroups by sleep duration (short: ≤6 hours, normal: 6-9 hours, and long: ≥9 hours) on weekdays and weekends and analyzed for the respective association with renal function using stratified multivariable linear regression.

Results

Weekend sleep duration for 9 hours or more was associated with decreasing estimated glomerular filtration rate (eGFR) levels by 2.8 to 6.4 mL/min/1.73 m2 among people with long to short weekday sleep duration compared with short weekday and weekend sleep durations (control group) after adjusting for demographic characteristics, body measurement, sleep quality, smoking, and comorbidities. The study population with short weekday sleep duration (sWK) and long weekend sleep duration (lWD) had the most significant decline in eGFR. For the study population with sWK, eGFR level significantly decreased by 1.1 mL/min/1.73 m2 as sleep duration on weekends increased by one hour.

Conclusion

The underlying mediators of lWD and CKD could be the dysregulation of human behaviors, metabolism, or biological functions. Longer weekend sleep duration was linked to a decrease in eGFR levels. It warrants further study to clarify the mediators.

Sleep apnoea syndrome prevalence in chronic kidney disease and end-stage kidney disease patients: a systematic review and meta-analysis

Background

Several studies have examined the frequency of sleep apnoea (SA) in patients with chronic kidney disease (CKD), reporting different prevalence rates. Our systematic review and meta-analysis aimed to define the clinical penetrance of SA in CKD and end-stage kidney disease (ESKD) patients.

Methods

Ovid-MEDLINE and PubMed databases were explored up to 5 June 2023 to identify studies providing SA prevalence in CKD and ESKD patients assessed by different diagnostic methods, either sleep questionnaires or respiration monitoring equipment [such as polysomnography (PSG), type III portable monitors or other diagnostic tools]. Single-study data were pooled using the random-effects model. The Chi2 and Cochrane-I2 tests were used to assess the presence of heterogeneity, which was explored performing sensitivity and/or subgroup analyses.

Results

A cumulative analysis from 32 single-study data revealed a prevalence of SA of 57% [95% confidence interval (CI) 42%-71%] in the CKD population, whereas a prevalence of 49% (95% CI 47%-52%) was found pooling data from 91 studies in ESKD individuals. The prevalence of SA using instrumental sleep monitoring devices, including classical PSG and type III portable sleep monitors, was 62% (95% CI 52%-72%) and 56% (95% CI 42%-69%) in CKD and ESKD populations, respectively. Sleep questionnaires revealed a prevalence of 33% (95% CI 16%-49%) and 39% (95% CI 30%-49%).

Conclusions

SA is commonly seen in both non-dialysis CKD and ESKD patients. Sleep-related questionnaires underestimated the presence of SA in this population. This emphasizes the need to use objective diagnostic tools to identify such a syndrome in kidney disease.

Lifestyle factors associated with a rapid decline in the estimated glomerular filtration rate over two years in older adults with type 2 diabetes-Evidence from a large national database in Japan

BACKGROUND

The present study investigated lifestyle risk factors from metabolic syndrome-related lifestyles for a rapid decline in the estimated glomerular filtration rate (eGFR) among adults aged 40-74 years with treated and untreated type 2 diabetes.

METHODS AND RESULTS

This study analyzed data from the National Database of Health Insurance Claims and Specific Health Checkups of Japan, encompassing the period from fiscal year (FY) 2017 to FY2020. We established FY2018 as our baseline year. The subjects of this study were adults aged 40-74 in FY2018(baseline) who had type 2 diabetes and underwent specific health checkups in FY2020. We excluded adults with a medical record of kidney dialysis between FY2017 and FY2018, records of suspected type 1 diabetes between FY2017 and FY2020, or a baseline eGFR >85 mL/min/1.73 m2 or missing eGFR data as of FY2020. Eventually we analyzed 573,860 individuals. The outcome variable was a rapid decline in eGFR (≥30%) during the follow-up. Exposure lifestyle factors included skipping breakfast, late-night dinners, regular smoking, a high alcohol intake, non-refreshing sleep, and a lack of habitual exercise. Logistic regression models were stratified by age (40-59 and 60-74 years) and baseline eGFR levels (60-85, 30-59, and <30 mL/min/1.73 m2). Covariates included sex, a history of heart disease, a history of stroke, a history of renal failure, anemia, low-density lipoprotein, systolic blood pressure, hemoglobin A1C, body mass index, antidiabetic medications, antihypertension drugs, lipid-lowering drugs, the oral adsorbent Kremezin, non-steroidal anti-inflammatory drugs, and drugs for the treatment of renal anemia. A rapid decline in eGFR was detected in approximately 1.3% of participants (7,683 cases). In the baseline eGFR >30 subgroups (60-85 or 30-59 mL/min/1.73 m2), skipping breakfast and regular smoking were associated with a rapid decline in eGFR in both age groups, while a lack of habitual exercise and late-night dinners in the 60-74 age group and non-refreshing sleep in the 40-59 age group were identified as risk factors. Additionally, skipping breakfast was a risk factor for a rapid decline in eGFR in the 60-74 age group regardless of baseline eGFR levels. In the baseline eGFR <30 mL/min/1.73 m2 subgroup, skipping breakfast and non-refreshed sleep were risk factors for a rapid decline in eGFR.

CONCLUSIONS

We found specific lifestyle risk factors were associated with a rapid eGFR decline among people with type 2 diabetes from a nationwide database in Japan. The associations varied by baseline eGFR level, age, and sex. Lifestyle modifications may effectively prevent the aggravation of diabetic kidney disease.

Sleep quality and associated factors among patients with chronic kidney disease in Nigeria: a cross-sectional study

OBJECTIVE

Poor sleep quality adversely affects the overall well-being and outcomes of patients with chronic kidney disease (CKD). However, it has not been well studied in Africans with CKD. We determined the prevalence of poor sleep quality and associated factors among patients with CKD.

DESIGN

This was a cross-sectional study that involved patients with CKD .

SETTINGS

The study was carried out in the outpatient clinic of nine hospitals in Nigeria.

METHODS

Sleep quality, depressive and anxiety symptoms and quality of life (QoL) were assessed among 307 patients with CKD using Pittsburgh Sleep Quality Index Questionnaire, Hospital Anxiety Depression Scale Questionnaire and 12-item Short Form Health Survey Quality of Life Questionnaire, respectively. The prevalence of poor sleep quality and associated factors were determined. A p<0.05 was considered as statistically significant.

RESULTS

The mean age of the study participants was 51.40±15.17 years. The male:female ratio was 1.5:1 One hundred and twenty-one (39.4%) of the patients were on maintenance haemodialysis (MHD). The prevalence of poor sleep quality, anxiety symptoms and depressive symptoms among the patients was 50.2%, 37.8% and 17.6%, respectively. The prevalence of poor sleep quality in the CKD stages 3, 4, 5 and 5D was 38.1%, 42.6%, 52.2% and 58.7%, respectively. The prevalence of poor sleep quality was significantly higher in MHD patients compared with predialysis CKD (59.5% vs 43.6%; p=0.008). Factors associated with poor sleep quality were CKD stage (p=0.035), anaemia (p=0.003), pruritus (p=0.045), anxiety symptoms (p≤0.001), depressive symptoms (p≤0.001) and reduced QoL (p≤0.001). On multivariate analysis, factors associated with poor sleep were anxiety (AOR 2.19; 95% CI 1.27 to 3.79; p=0.005), anaemia (AOR 5.49; 95% CI 1.43 to 21.00;p=0.013) and reduced physical component of QoL (AOR 4.11; 95% CI 1.61 to 10.47; p=0.003).

CONCLUSION

Poor sleep quality is common among patients with CKD especially in the advanced stage. The significant factors associated with poor sleep quality were QoL, anaemia and anxiety symptoms. These factors should be adequately managed to improve the overall outcomes of patients with CKD.

Correlation of plasma metabolites and comorbid illnesses with poor sleep quality in patients with coronary heart disease

PURPOSE

This study aimed to examine the relationship between plasma metabolites (biochemical parameters) and comorbid illnesses with sleep quality in individuals with coronary heart disease (CHD).

METHODS

This descriptive cross-sectional study was conducted between 2020 and 2021 at a university hospital. Hospitalized patients with a diagnosis of CHD were analyzed. The Personal Information Form' and Pittsburgh Sleep Quality Index (PSQI) were used to collect data. Laboratory findings including plasma metabolites were examined.

RESULTS

Of 60 hospitalized patients with CHD, 50 (83%) had poor sleep quality. A positive and statistically significant correlation was found between the plasma metabolite blood urea nitrogen and poor sleep quality (r = 0.399; p = 0.002). The presence of CHD and additional chronic diseases (especially diabetes mellitus, hypertension, and chronic kidney disease) are important parameters associated with the risk of poor sleep quality (p = 0.040 < 0.05).

CONCLUSION

Increases in blood urea nitrogen level in individuals with CHD are associated with worse sleep quality. Additional chronic diseases coexisting with CHD correlate with increased risk of poor sleep quality.

Depressive symptoms and sleep duration in relation to chronic kidney disease: Evidence from the China health and retirement longitudinal study

OBJECTIVE

Nowadays, the joint effects of depressive symptoms and sleep duration on the risk of chronic kidney disease (CKD) are still unclear. We aimed to prospectively assess the combined effect of depressive symptoms and sleep duration on the incidence of CKD in middle-aged and elderly Chinese population.

METHODS

A total of 10,953 participants from the China Health and Retirement Longitudinal Study (CHARLS) were included. Depressive symptoms were measured using the 10-item Center for Epidemiological Studies Depression scale (CESD-10). Sleep duration was evaluated by self-reported. CKD events were based on self-reported physicians' diagnosis or personal estimate glomerular filtration rate level (eGFR <60 mL/min/1.73 m2). Cox regression models were established to analyze the correlation between depressive symptoms, sleep duration and the risk of CKD.

RESULTS

Over a mean follow-up time was 6.76 ± 0.98 years, 851 (7.8%) participants had reported CKD events during the follow-up. Elevated depressive symptoms (HR = 1.65, 95% CI = 1.43-1.90) and short sleep duration (HR = 1.48, 95% CI = 1.27-1.72) were independently associated with an increased CKD risk after adjusting for potential confounding factors. Participants with short sleep duration (< 6 h)/elevated depressive symptoms (HR = 2.24, 95% CI = 1.89-2.65) were associated with the highest risk of CKD than those with normal sleep duration/low depressive symptoms.

CONCLUSIONS

Elevated depressive symptoms and short sleep duration were independent risk factors for CKD. There was a combined effect between depressive symptoms and sleep duration in increasing the risk of CKD.

The relationship between obstructive sleep apnea and risk of renal impairment in patients with hypertension, a longitudinal study

OBJECTIVE

Association of obstructive sleep apnea (OSA) with renal damage is undetermined, especially in the population with hypertension, a high-risk group for chronic kidney disease. Therefore, we aimed to explore whether OSA is an independent risk factor for renal impairment in patients with hypertension, by considering the effects of gender, age, obesity and OSA severity.

METHODS

The longitudinal observational study included patients with hypertension and suspected OSA without renal damage at baseline who visited Hypertension Center between January 2011 and December 2018, and followed up till renal outcomes, death, loss to follow-up, or May 31, 2022, using annual health check-ups, hospital readmission or out-patient visits. Main renal outcome was chronic kidney disease (CKD), defined as estimated glomerular filtration rate <60 ml/min per 1.73 m2 and/or positive proteinuria. Cox proportional hazard models were used to evaluate the association, and repeated after propensity score matching. Sensitivity analysis were performed by excluding those with primary aldosteronism.

RESULTS

7961 patients with hypertension were included with 5022 ones with OSA, and 82% were followed up. During median follow-up of 3.42 years, 1486 patients developed CKD. Per 1000 person-year incidence of CKD was 56.72 in OSA group. In Cox regression analysis, OSA and severe OSA group respectively showed 1.21 (95% CI: 1.08-1.35) and 1.27 (95% CI: 1.09-1.47) fold risk for CKD in total, compared with non-OSA group. Overall results remained consistent in propensity score matching and sensitivity analysis.

CONCLUSION

OSA is independently associated with higher risk of chronic kidney disease in hypertension.

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 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.

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.

Association between sleep duration and quality with rapid kidney function decline and development of chronic kidney diseases in adults with normal kidney function: The China health and retirement longitudinal study

Research have shown that sleep is associated with renal function. However, the potential effects of sleep duration or quality on kidney function in middle-aged and older Chinese adults with normal kidney function has rarely been studied. Our study aimed to investigate the association of sleep and kidney function in middle-aged and older Chinese adults. Four thousand and eighty six participants with an eGFR ≥60 ml/min/1.73 m² at baseline were enrolled between 2011 and 2015 from the China Health and Retirement Longitudinal Study. Survey questionnaire data were collected from conducted interviews in the 2011. The eGFR was estimated from serum creatinine and/or cystatin C using the Chronic Kidney Disease Epidemiology Collaboration equations (CKD-EPI). The primary outcome was defined as rapid kidney function decline. Secondary outcome was defined as rapid kidney function decline with clinical eGFR of <60 ml/min/1.73 m² at the exit visit. The associations between sleep duration, sleep quality and renal function decline or chronic kidney disease (CKD) were assessed based with logistic regression model. Our results showed that 244 (6.0%) participants developed rapid decline in kidney function, while 102 (2.5%) developed CKD. In addition, participants who had 3-7 days of poor sleep quality per week had higher risks of CKD development (OR 1.86, 95% CI 1.24-2.80). However, compared with those who had 6-8 h of night-time sleep, no significantly higher risks of rapid decline in kidney function was found among those who had <6 h or >8 h of night time sleep after adjustments for demographic, clinical, or psychosocial covariates. Furthermore, daytime nap did not present significant risk in both rapid eGFR decline or CKD development. In conclusion, sleep quality was significantly associated with the development of CKD in middle-aged and older Chinese adults with normal kidney function.

Comprehensive analysis of differentially expressed miRNAs in mice with kidney injury induced by chronic intermittent hypoxia

Background: miRNAs have been reported to participate in various diseases. Nevertheless, the expression patterns of miRNA in obstructive sleep apnea (OSA)-induced kidney injury remain poorly characterized. In the current study, miRNA sequencing (miRNA-seq) was conducted to investigate miRNA expression profiles in a chronic intermittent hypoxia (CIH)-induced renal injury mouse model.

Methods: The mouse model of chronic intermittent hypoxia was established. Differentially expressed miRNAs (DEmiRs) were detected using miRNA-seq technology. The sequencing data were subjected to Gene Ontology (GO) functional enrichment and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses using a bioinformatics approach. RT-qPCR was further used to evaluate the sequencing results. Finally, we created a network for clarifying the relationship between the miRNAs and target genes.

Results: In total, nine miRNAs were identified to be upregulated and nine to be downregulated in a mouse model of renal injury induced by chronic intermittent hypoxia. The Kyoto Encyclopedia of Genes and Genomes analyses revealed that the Wnt signaling pathway was involved in the development of chronic intermittent hypoxia-induced renal injury. Subsequently, eight DEmiRs, namely, mmu-miR-486b–3p, mmu-miR-215–5p, mmu-miR-212–3p, mmu-miR-344–3p, mmu-miR-181b-1-3p, mmu-miR-467a–3p, mmu-miR-467 d-3p, and mmu-miR-96–5p, showed a similar trend of expression when verified using RT-qPCR. Finally, five selected DEmiRs were used to construct a miRNA–mRNA network.

Conclusion: In conclusion, a total of 18 DEmiRs were identified in the mouse model of chronic intermittent hypoxia-induced renal injury. These findings advance our understanding of the molecular regulatory mechanisms underlying the pathophysiology of obstructive sleep apnea-associated chronic kidney disease.

Prevalence and related factors of poor sleep quality in patients with pre-dialysis chronic kidney disease

BACKGROUND

Sleep disturbances in patients with chronic kidney disease (CKD) are related to decreased quality of life and increased health-related risks. There is insufficient data about actual prevalence and related factors of poor sleepers in this group. In this study, we aimed to investigate prevalence and related risk factors of self-reported poor sleep quality in patients with pre-dialysis CKD.

METHODS

In this cross-sectional study, 259 pre-dialysis CKD patients (median age 56 years; range, 19-85) were included. Demographical, clinical and laboratory correlates were recorded. Body mass index (BMI) was calculated. Estimated glomerular filtration rate (eGFR) was calculated by the Modification of Diet in Renal Disease (MDRD) formula. Sleep quality was assessed by Pittsburgh Sleep Quality Index (PSQI), a self-rated questionnaire. Depression was evaluated using the Beck Depression Inventory (BDI).

RESULTS

Median eGFR was 27.6 ml/min/1.73 m² (range, 9-56). Of the 259 patients, 110 (42.5%) were poor sleepers with global PSQI score >5. The univariate correlation analysis revealed that global PSQI score was positively correlated with age, BMI, waist circumferences (WC), hip circumferences (HC), serum phosphorus and triglyceride levels, systolic blood pressure (BP), pulse pressure and BDI score, and negatively correlated with male gender and hemoglobin level. Logistic regression analysis, showed that HC, systolic BP, and BDI scores were independently associated with poor sleep quality (p = 0.001, p = 0.020 and p < 0.001, respectively).

CONCLUSION

Prevalence of poor sleep quality in our pre-dialysis CKD patients was 42.5%. Systolic BP, depression and HC, all of these are potentially correctable factors, were associated with poor sleep quality independently.

Leveraging genetic discoveries for sleep to determine causal relationships with common complex traits

Sleep occurs universally and is a biological necessity for human functioning. The consequences of diminished sleep quality impact physical and physiological systems such as neurological, cardiovascular, and metabolic processes. In fact, people impacted by common complex diseases experience a wide range of sleep disturbances. It is challenging to uncover the underlying molecular mechanisms responsible for decreased sleep quality in many disease systems owing to the lack of suitable sleep biomarkers. However, the discovery of a genetic component to sleep patterns has opened a new opportunity to examine and understand the involvement of sleep in many disease states. It is now possible to use major genomic resources and technologies to uncover genetic contributions to many common diseases. Large scale prospective studies such as the genome wide association studies (GWAS) have successfully revealed many robust genetic signals associated with sleep-related traits. With the discovery of these genetic variants, a major objective of the community has been to investigate whether sleep-related traits are associated with disease pathogenesis and other health complications. Mendelian Randomization (MR) represents an analytical method that leverages genetic loci as proxy indicators to establish causal effect between sleep traits and disease outcomes. Given such variants are randomly inherited at birth, confounding bias is eliminated with MR analysis, thus demonstrating evidence of causal relationships that can be used for drug development and to prioritize clinical trials. In this review, we outline the results of MR analyses performed to date on sleep traits in relation to a multitude of common complex diseases.

Association of insomnia and short sleep duration, alone or with comorbid obstructive sleep apnea, and the risk of chronic kidney disease

STUDY OBJECTIVES

Obstructive sleep apnea (OSA), sleep fragmentation, and short sleep duration (SD) have been associated with chronic kidney disease (CKD). However, these potential mechanisms for CKD have not been compared in the same cohort. This study investigated the independent and combined impact of OSA and insomnia with short sleep duration on the risk of CKD progression in a sleep clinic population.

METHODS

In a cross-sectional study design, adults with suspected OSA completed an overnight sleep study and a questionnaire that included the Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI). They also provided blood and urine samples for measurement of the glomerular filtration rate and urine albumin:creatinine ratio, from which the risk of CKD progression was determined.

RESULTS

Participants (n = 732, 41% female, 55 ± 13 years) were categorized into four groups: no/mild OSA without insomnia (NM-OSA, n = 203), insomnia with SD without OSA (Insomnia-SD, n = 104), moderate-to-severe OSA without insomnia (MS-OSA, n = 242), and comorbid insomnia and OSA with SD (COMISA-SD, n = 183). After stratification, 12.8% of NM-OSA, 15.4% of Insomnia-SD, 28.9% of MS-OSA, and 31.7% of the COMISA-SD participants had an increased risk of CKD progression. Compared to NM-OSA, the odds ratio (OR) for an increased risk of CKD progression was not increased in Insomnia-SD (OR 0.95, confidence interval [CI]: 0.45-1.99) and was increased to the same degree in MS-OSA (OR 2.79, CI: 1.60-4.85) and COMISA-SD (OR 3.04, CI: 1.69-5.47). However, the ORs were similar between the MS-OSA and COMISA-SD groups across all statistical models (p ≥ .883).

CONCLUSIONS

In a sleep clinic population, insomnia with short sleep duration does not increase the risk of CKD progression; nor does it further increase the risk of CKD progression associated with moderate-to-severe OSA.

The mediating effect of sleep quality and fatigue between depression and renal function in nondialysis chronic kidney disease: a cross-sectional study

BACKGROUND

Depressive symptoms, fatigue, and poor sleep quality are associated with renal function deterioration in patients with nondialysis chronic kidney disease (CKD-ND). This study was designed to examine whether fatigue and sleep quality are mediators of the association between depression and renal function.

METHODS

This study adopted a cross-sectional study design. Patients with CKD-ND aged 20 years or older were recruited by purposive sampling at a medical center in Central Taiwan from December 2020 to July 2021. Data were collected using the Emotional and Social Support Scale, Fatigue Scale, Beck Depression Inventory-II (BDI-II), and Pittsburgh Sleep Quality Index. Medical records were reviewed to obtain the estimated glomerular filtration rate (eGFR) for the next month. The relationships among variables were analyzed using structural equation modeling to assess the goodness-of-fit of the model. Then, the bootstrapping method was used to analyze the mediated effect.

RESULTS

Two hundred forty-two participants (mean age 70.5 years and 53% males) were included in the analysis. About 39% of the participants met the criteria for depressive symptoms in BDI-II, and 91% reported having sleep disturbances. Participants' degree of fatigue was not high (20.4 ± 13.3). The average eGFR was 25.45 mL/min/1.73 m ² (± 13.36). The results showed that fatigue, sleep quality, and eGFR were significantly correlated with depression. The total effect size was - 0.8304 (95% confidence interval [CI], - 0.9602 to - 0.7006), and the indirect effect size was - 0.1738 (95% CI, - 0.2812 to - 0.0651), which was a statistically significant difference, indicating that the model has a mediating effect. According to mediation analysis, fatigue and sleep quality had a significant indirect effect on the relationship between depression and renal function (95% CI, - 0.0587 to - 0.0039).

CONCLUSIONS

The findings suggest that fatigue and poor sleep quality may mediate the association between depression and renal function.

Associations between nutritional factors and excessive daytime sleepiness in older patients with chronic kidney disease

BACKGROUND

Excessive daytime sleepiness (EDS) is prevalent in not only older adults, but also patients with chronic kidney disease (CKD), and is associated with higher risks of morbidity and mortality.

AIMS

The aim of the present study is to determine associations between EDS and nutritional status and serum nutrient levels in older patients with CKD.

METHODS

This cross-sectional study included 367 patients (aged ≥ 65 years) with CKD (eGFR < 60 ml/min/1.73 m² and/or > 30 mg/day of albuminuria for > 3 months). EDS was recorded using the Epworth Sleepiness Scale (a score of ≥ 11). Malnutrition was diagnosed according to the Mini Nutritional Assessment (MNA) tool (a score of < 17).

RESULTS

The mean age was 81 ± 7 years, and 248 (67%) were female. EDS was seen in 99 (26.9%) patients. Those with EDS had significantly lower MNA scores and more frequent malnutrition than those without EDS (p < 0.05). In multivariable analysis adjusted for age, sex, cerebrovascular disease, dementia, number of drugs, and number of urinations at night, and the Charlson Comorbidity Index the relationship between malnutrition and EDS persisted (OR 2.58, 95% CI 1.38-4.83, p = 0.003). There was no significant difference between the presence of EDS and serum levels or deficiencies of vitamin D, vitamin B₁₂, and folate (p > 0.05).

CONCLUSIONS

EDS is associated with malnutrition in older patients with CKD. Therefore, EDS and nutritional status should be evaluated together in clinical practice. However, future studies are needed to determine the direction of the association between malnutrition and EDS and to evaluate if dietary intervention can improve EDS.

Racial disparity in sleep apnea-related mortality in the United States

BACKGROUND

Sleep apnea is one of the most common sleep disorders in the United States (US). Although the prevalence, risk factors, and clinical presentations of sleep apnea vary by racial groups, the racial disparity in sleep apnea-related mortality remains unclear.

METHODS

Sleep apnea-related mortality for 1999-2019 was obtained from the National Center for Health Statistics provided by the Centers for Disease Control and Prevention. We examined the mortality trends for sleep apnea using Joinpoint regression analysis and compared the associated outcomes and multiple causes of death between Blacks and Whites.

RESULTS

For 1999-2019, sleep apnea was documented as the underlying cause of death in 17,053 decedents, with 2593 Blacks and 14,127 Whites. The overall age-adjusted mortality rates in all population, Blacks, and Whites were 2.5, 3.5, and 2.4 per 1,000,000 population, respectively (P < 0.001). Both Blacks and Whites had the highest mortality rates in the Midwest and the lowest in the Northeast. Despite the flattened mortality trend in the last decade overall, Black males had a continuous mortality increase over the study period (Annual Percentage Change 2.7%, 95% CI: 1.2-4.2). For both genders of sleep apnea decedents, Blacks were more likely to have multiple cause of death of Cardiac Arrest, Hypertension, Obesity, and Chronic Renal Failure, but Arrhythmia was more common in Whites (P < 0.05).

CONCLUSIONS

There is a significant racial disparity in sleep apnea-related mortality in the US. The uptrend in mortality in Black males and associated outcomes related to cardiovascular disease should raise concerns specifically in Blacks with sleep apnea.

Association of sleep characteristics with renal function in menopausal women without recognized chronic kidney disease

OBJECTIVE

To delineate the association between sleep characteristics and renal function in peri-post menopause free of Chronic kidney disease (CKD) as well as cardiometabolic and hormone indicators.

METHODS

Cross-sectional data from a total of 823 Han-Chinese women aged 40-67 years who visited the Menopause Clinic in the Shanghai Sixth People's Hospital from November 2011 to November 2020 were analyzed through the Pittsburgh Sleep Quality Index (PSQI) and serum cystatin C (Cys-C). Logistic regression models were used to assess the association between cumulative/each sleep parameter and renal function after adjusting for cardiometabolic variables.

RESULTS

After confounding factors, we identified that poor perceived sleep quality, shorter sleep duration (<6 h), low sleep efficiency (<75%), delayed sleep latency and worse sleep disturbance elevated more than doubled the odds ratio for declining renal function (≥0.91 mg/dL, the highest Cys-C) in postmenopause in a graded fashion. Meanwhile, multiple logistic regression analysis revealed that sleep disorder (PSQI ≥ 8), late postmenopause, highest quartile independently increased the odds ratio for declining renal function (OR 2.007, 95% CI: 1.408-2.861, OR = 3.287, 95%CI: 3.425-8.889, OR = 2.345, 95% CI: 1.310-4.199, respectively), while participants with menopausal hormone replacement (MHT) lower the odds of declining renal function (OR = 0.486, 95% CI: 0.324-0.728).

CONCLUSION

The findings proposed that maintaining good sleep quality should be attached great importance to postmenopausal women, which provides clinical evidence for the feasible early detection and effective prevention such as MHT of renal disease progression in postmenopausal women.

Heart Failure with Preserved Ejection Fraction and Obstructive Sleep Apnea: A Novel Paradigm for Additional Cardiovascular Benefit of SGLT2 Inhibitors in Subjects With or Without Type 2 Diabetes

After examining the complex interplay between heart failure (HF) in its various clinical forms, metabolic disorders like nonalcoholic fatty liver disease (NAFLD), and obstructive sleep apnea (OSA) syndrome, in this mini-review we described possible favorable effects of sodium-glucose cotransporter 2 inhibitors (SGLT2is) on HF with preserved (i.e., ≥ 50%) ejection fraction (HFpEF) through enhanced cardiorenal function and visceral-subcutaneous body fat redistribution. In greater detail, on the basis of pathophysiological mechanisms underlying OSA onset and the direct positive SGLT2i effect on renal function benefiting chronic kidney disease, we emphasized the promising role of SGLT2is in prevention, rehabilitation, and treatment of patients with OSA regardless of coexisting type 2 diabetes (T2DM). Indeed, SGLT2is enhance lipolysis and fatty acid beta-oxidation. These phenomena might prevent OSA by reducing the size of visceral and subcutaneous adipose tissue and, as proven in humans and animals with T2DM, counteract NAFLD onset and progression. The aforementioned mechanisms may represent an additional SGLT2i cardioprotective effect in terms of HFpEF prevention in patients with OSA, whose NAFLD prevalence is estimated to be over 50%.

Effect of depression on progression to end-stage renal disease or pre-end-stage renal disease death in advanced diabetic nephropathy: A prospective cohort study of the Diabetes Study from the Center of Tokyo Women's Medical University

AIMS/INTRODUCTION

This study aimed to determine the effect of depression on the progression to end-stage renal disease (ESRD) and pre-ESRD death in patients with advanced diabetic nephropathy.

MATERIALS AND METHODS

This single-center prospective cohort study enrolled Japanese patients with type 2 diabetes and advanced diabetic nephropathy. The total Patient Health Questionnaire-9 score was used to evaluate depression at baseline and classified patients into: no, mild and severe depression groups. The outcomes were ESRD, defined as initiation of renal replacement therapy, and pre-ESRD death. The relationship between the severity of depression and these outcomes was analyzed using a competing risks model, defining each outcome as the competing risk of the other outcome.

RESULTS

Of the 486 patients with a mean estimated glomerular filtration rate of 37.1 ± 21.1 mL/min/1.73 m2 , 345 were men. During the median follow up of 4.4 years, 164 patients progressed to ESRD and 50 died. The cumulative incidence function of ESRD was significantly higher in the severe depression group (Gray's test, P = 0.003). The ESRD risk increased by 12.4% and 45.1% in patients with mild and severe depression, respectively, compared with those without depression, although these differences did not reach statistical significance in the multivariate subdistribution hazard model (P = 0.450 and 0.161, respectively). The cumulative incidence of death was similar for the study groups.

CONCLUSION

Depression potentially has a weak impact on progression to ESRD, however, the presence of comorbidities might have the possibility to reduce the effect of depression on the renal outcome in patients with advanced diabetic nephropathy.

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.

Possible Preventative/Rehabilitative Role of Gliflozins in OSA and T2DM. A Systematic Literature Review-Based Hypothesis

Obstructive sleep apnoea (OSA) is characterized by frequent apnoea episodes during sleep due to upper airway obstruction. The present review summarizes current knowledge on inter-relationships between OSA and type 2 diabetes mellitus (T2DM) and suggests the former as a possible target for sodium-glucose co-transporter-2 inhibitors (SGLT-2i). Based on pathophysiological mechanisms underlying OSA onset and renal SGLT-2 effects, we suggest that SGLT-2i indications might expand beyond current ones, including glucose, lipids, uric acid, blood pressure, and body weight control as well as chronic heart failure and kidney disease prevention.

Sleep apnea is associated with residual kidney function and mortality in patients with peritoneal dialysis: Prospective cohort study

INTRODUCTION

Fluid overload and sleep apnea (SA) are known risk factors for mortality in dialysis patients. Although incidence and severity of SA were shown higher in peritoneal dialysis (PD) patients than in hemodialysis patients, data regarding the association of SA with body fluid status and mortality are limited. Therefore, the association of SA with body fluid status and mortality were investigated in a prospective cohort with patients undergoing PD.

METHODS

The present study included 103 prevalent PD patients who were followed up for median 70 months. At baseline, the subjects underwent in-home polysomnography, bioelectrical impedance analysis, and urea kinetics. Excessive daytime sleepiness and sleep quality were assessed using sleep questionnaires. SA was defined as apnea/hypopnea index higher than 15 events per hour.

RESULTS

Sleep apnea was diagnosed in 57 (55.3%) patients (SA group); the subjects had significantly higher extracellular water (10.3 ± 1.4 vs. 9.2 ± 1.8, p = 0.001) and lower residual kidney function (RKF) (3.3 ± 3.3 vs. 5.9 ± 7.2, p = 0.02) compared with subjects in the non-SA group. SA was significantly associated with RKF [odds ratio, 0.84; 95% confidence interval (CI), 0.73-0.97] in multivariable logistic regression analysis. In multivariable Cox regression models, SA was a significant predictor of mortality in PD patients (adjusted hazard ratio, 5.74; 95% CI, 1.09-30.31) after adjusting for well-known risk factors.

CONCLUSIONS

Sleep apnea was very common in PD patients and significantly associated with lower RKF. SA was also a novel risk predictor of mortality in PD patients.

Short sleep duration increases the risk of hyperuricemia among Chinese adults: findings from the China Health and Nutrition Survey

STUDY OBJECTIVES

Hyperuricemia is a growing public health problem with its increasing prevalence. Few studies have investigated the association between sleep duration and hyperuricemia. The objective of this study is to explore whether short sleep duration is an independent risk factor of hyperuricemia in Chinese adults.

METHODS

The data we analyzed was extracted from the 2009 wave of the China Health and Nutrition Survey. The population we analyzed included 8289 participants aged 18 years or older with sleep of 5-10 h per 24 h. We categorized the population into three groups by sleep duration: 5-6 h (short sleeper),7-8 h (regular sleeper), and 9-10 h (long sleeper). Hyperuricemia was defined as serum uric acid ≥7 mg/dL in men and ≥6 mg/dL in women.

RESULTS

Among the three groups, 9.8% were short sleepers, 68.4% were regular sleepers and 21.8% were long sleepers. The prevalences of hyperuricemia were 19.5%,15.2% and 15.5% respectively. The risks of hyperuricemia in regular and long sleep groups were lower than short sleep group, and the association remained after adjusting for indexes including age, gender, chronic kidney disease, hypertension, diabetes mellitus, high low-density lipoprotein cholesterol (LDL-c), and obesity. In subgroup analysis, we found the association was still observed in participants without hypertension, diabetes mellitus or obesity.

CONCLUSIONS

Our findings suggest that short sleep duration is associated with higher risk of hyperuricemia independently of cardiometabolic risk factors, especially in individuals without traditional hyperuricemia risk factors.

Impact of Sleep Duration on Mortality and Quality of Life in Chronic Kidney Disease: Results from the 2007-2015 KNHANES

INTRODUCTION

In the general population, short and long sleep durations have been associated with adverse health outcomes. However, this association remains unclear in patients with chronic kidney disease (CKD). We examined the relationship of sleep duration to mortality and health-related quality of life (HRQOL) in individuals with CKD.

METHODS

A total of 1,783 adults with CKD who participated in the 2007-2015 Korea National Health and Nutrition Examination Survey were analyzed. CKD was defined as an estimated glomerular filtration rate of <60 mL/min per 1.73 m2. Participants were categorized into 3 groups according to self-reported sleep duration: <6 h (short sleepers), 6-8 h, and >8 h (long sleepers). The outcome variables were all-cause mortality and HRQOL. HRQOL was assessed using the European Quality of Life-5 Dimensions (EQ-5D) index.

RESULTS

During a median of 6.4 years, 481 (27%) deaths occurred. In unadjusted Cox regression analysis, long sleepers with CKD had an increased risk of death (hazard ratio [HR], 1.62; 95% confidence interval [CI]: 1.26-2.09). This significant association remained after adjusting for age, sex, and BMI (HR, 1.36; 95% CI: 1.05-1.75); however, it was lost after adjusting for CKD stage, social and lifestyle factors, and presence of comorbidities (HR, 1.15; 95% CI: 0.89-1.49). Compared with 6- to 8-h sleepers with CKD, long sleepers with CKD had significantly worse HRQOL in multivariable linear regression models. The adjusted means of the EQ-5D index were 0.80 (95% CI: 0.77-0.82) for short sleepers, 0.81 (95% CI: 0.80-0.82) for 6- to 8-h sleepers, and 0.76 (95% CI: 0.73-0.79) for long sleepers (p = 0.01).

DISCUSSION/CONCLUSION

Long sleep duration is associated with poor HRQOL in Korean adults with CKD. The weak association between long sleep duration and mortality was attenuated after multivariable adjustment in this study.

A nonrandomised pilot study to examine the feasibility and acceptability of reflexology in patients undergoing hospital-based haemodialysis (solitude study)

BACKGROUND

Patients with end-stage kidney disease, receiving haemodialysis can experience complications-hypotension, headache, muscle cramp, chest pain, nausea and vomiting. Patients who experience all or some of these symptoms will often report reduced health-related quality of life (HRQOL) and poor sleep quality, which may lead to increased morbidity and mortality.

OBJECTIVE

The objective of this pilot study is to evaluate the feasibility of a larger randomised controlled trial to determine the effect of foot reflexology on a cohort of patients undergoing hospital-based haemodialysis.

DESIGN

A nonrandomised pilot study using a multimethod approach.

PARTICIPANTS

Twenty patients undergoing hospital-based haemodialysis treatment.

MEASUREMENTS

HRQOL and quality of sleep were measured using the SF-12 Health Survey and the Pittsburgh Sleep Quality Index (PSQI). Semi-structured interviews were completed with 10 patients, exploring their experiences, opinions and perceptions of the intervention.

RESULTS

There was an increase in the mean scores examining the total physical health and mental health components of the SF-12. All corresponding p values were statistically significant following the intervention. The mean total sleep score postintervention signified positive changes in sleep quality, with the corresponding p values being statistically significant. The study established the feasibility of the intervention and the benefits for patients undergoing haemodialysis.

CONCLUSION

This pilot study demonstrated the possibility of recruiting and retaining patients undergoing haemodialysis to a reflexology study. The study did not impact the haemodialysis routine and was positively received. The intervention showed statistically significant improvements in patients' HRQOL and sleep quality.

Impact of inflammatory markers on the relationship between sleep quality and diabetic kidney disease

PURPOSE

Both poor sleep and diabetic kidney disease are closely associated with inflammation. However, the correlation between poor sleep and diabetic kidney disease has not been well clarified. Thus, the aim of this study was to determine the mediating role that inflammatory markers play in the pathogenic effect of poor sleep on the severity of diabetic kidney disease (DKD).

METHODS

A cross-sectional survey was conducted on 336 patients with type 2 diabetes (T2D). DKD was diagnosed according to the guidelines of the National Kidney Foundation-Kidney Disease Outcome Quality Initiative (NKF-K/DOQI). The Pittsburg Sleep Quality Index (PSQI) score was applied to assess patients for the quality of their sleep. Patients with a PSQI score of more than 5 were assigned to the poor sleep group, and the rest of the patients were assigned to the good sleep group. Circulating levels of six inflammatory biomarkers related to poor sleep and DKD were measured.

RESULTS

The prevalence of DKD was higher in patients with poor sleep quality than in those with good sleep quality (42% vs. 25%, P = 0.002). After adjustment, poor sleep quality (PSQI score OR 1.075 [95%CI 1.018-1.135], P = 0.009) remained independently associated with DKD. PSQI score was found to be positively related to fibroblast growth factor (FGF23), interleukin 6 (IL-6), P-selectin, and intercellular adhesion molecule-1 (ICAM-1) (P < 0.01), rather than fibrinogen and C-reactive protein (CRP) in linear regression models. As revealed by multiple mediation analysis, FGF23 and IL-6 mediated 26% and 23% of the relationship between PSQI score and urinary microalbumin (UMA), respectively. Similarly, the FGF23 and ICAM-1, instead of IL-6 and P-selectin, mediated 32% and 24% of the association between PSQI and estimated glomerular filtration rate (eGFR), respectively.

CONCLUSIONS

Poor sleep quality is independently associated with DKD. These results suggest that inflammatory markers contribute to a pathogenic connection between poor sleep and DKD.

Risk Factors for CKD Progression: Overview of Findings from the CRIC Study

The Chronic Renal Insufficiency Cohort (CRIC) Study is an ongoing, multicenter, longitudinal study of nearly 5500 adults with CKD in the United States. Over the past 10 years, the CRIC Study has made significant contributions to the understanding of factors associated with CKD progression. This review summarizes findings from longitudinal studies evaluating risk factors associated with CKD progression in the CRIC Study, grouped into the following six thematic categories: (1) sociodemographic and economic (sex, race/ethnicity, and nephrology care); (2) behavioral (healthy lifestyle, diet, and sleep); (3) genetic (apoL1, genome-wide association study, and renin-angiotensin-aldosterone system pathway genes); (4) cardiovascular (atrial fibrillation, hypertension, and vascular stiffness); (5) metabolic (fibroblast growth factor 23 and urinary oxalate); and (6) novel factors (AKI and biomarkers of kidney injury). Additionally, we highlight areas where future research is needed, and opportunities for interdisciplinary collaboration.

Continuous Positive Airway Pressure Improves Renal Function in Obese Patients With Obstructive Sleep Apnea Syndrome

Background: Obstructive sleep apnea syndrome (OSAS) is an independent risk factor for cardiovascular morbidity and mortality, and it has a detrimental effect on renal function. Obesity is the major risk factor for OSAS, and represents a risk factor for chronic kidney disease. Continuous positive airway pressure (CPAP) is the suggested therapy for moderate-to-severe OSAS. We designed this study to evaluate the effect of CPAP on estimated glomerular filtration rate (e-GFR) in a cohort of obese patients with moderate-to-severe OSAS and normal renal function. Methods: We enrolled 198 obese subjects, divided into two groups (OSAS+ and OSAS-), on the basis of cardiorespiratory monitoring; mild OSAS patients (n = 33) were excluded from the study, thus the analyses were conducted on 165 patients. Comparisons between groups were made by Student t-test or χ² test as appropriate. Linear regression analyses were used to assess the relationship between baseline e-GFR and different covariates and, in the OSAS+ group, between Δe-GFR and different covariates. A multivariate regression analysis was performed to determinate the independent predictor of the Δe-GFR. Results: OSAS+ subjects showed significantly increased values of systolic blood pressure, HOMA, pulse wave velocity, high-sensitivity C reactive protein and uric acid compared with OSAS- group. OSAS+ group showed significantly lower values of e-GFR and increased values of microalbuminuria. At linear regression analysis e-GFR resulted significantly and inversely related to AHI in the whole study population and in the two groups. After 6 months of CPAP therapy, OSAS+ subjects showed an improvement in respiratory parameters, as well as a significant increase in e-GFR values (104.2 + 19.0 vs. 84.0 + 13.1 ml/min/1.73 m², P < 0.0001). At multiple regression analysis, Δ apnea/hypopnea index (AHIa) resulted the main independent predictor of Δe-GFR explaining 22% of its variation. Conclusions: Obese OSAS patients show significantly lower values of e-GFR, even if in the normal range, compared with obese non-OSAS subjects. After 6 months of CPAP, e-GFR significantly improved (+20 ml/min/1.73 m²) and ΔAHIa resulted the most important independent predictor of Δe-GFR.

Obstructive sleep apnea during rapid eye movement sleep in patients with diabetic kidney disease

STUDY OBJECTIVES

Although recent studies suggest that obstructive sleep apnea during rapid eye movement (REM) is associated with different cardiometabolic and neurocognitive risks compared with non-REM (NREM) sleep, there is no information on whether obstructive sleep apnea during REM and/or NREM sleep is independently associated with diabetic kidney disease (DKD).

METHODS

In this cross-sectional study, 303 patients with type 2 diabetes who were followed up at our diabetes outpatient clinic underwent all-night polysomnography. Logistic regression analysis was performed to determine the separate effects of obstructive sleep apnea during REM and/or NREM sleep (REM and/or NREM-apnea-hypopnea index [AHI]) and several other polysomnography parameters on DKD after adjustment for several known risk factors for DKD.

RESULTS

The median (interquartile range) AHI, REM-AHI, and NREM-AHI of the patients (age 57.8 ± 11.8 years, male sex 86.8%, hypertension 64.3%, and DKD 35.2%) were 29.8 (18.0-45.4), 35.4 (21.1-53.3), and 29.1 (16.3-45.4) events/h, respectively. REM-AHI quartiles, but not NREM-AHI quartiles, correlated independently and significantly with DKD (P = .03 for linear trend, odds ratio (OR), and 95% confidence interval for Q2: 3.14 (1.10-8.98), Q3: 3.83 (1.26-11.60), Q4: 4.97 (1.60-15.46), compared with Q1). In addition, categorical AHI (P = .01, OR, and 95% confidence interval for ≥ 15 to < 30: 1.54 (0.64-3.71), ≥ 30: 3.08 (1.36-6.94) compared with < 15), quartiles of AHI (P = .01), quartiles of lowest arterial oxyhemoglobin saturation (P < .01), quartiles of percentage of time spent with arterial oxyhemoglobin saturation < 90 (P < .01), and quartiles of mean arterial oxyhemoglobin saturation were independently associated with DKD.

CONCLUSIONS

Obstructive sleep apnea, especially during REM sleep, is a potential risk factor for DKD.

Longer sleep duration may negatively affect renal function

BACKGROUND

Observational studies evaluating the link between sleep duration and kidney function reported controversial results. In the present study, Mendelian randomization analysis was applied to obtain unconfounded estimates of the casual association of genetically determined sleep duration with estimated glomerular filtration rate and the risk of chronic kidney disease.

METHODS

Data from the largest genome-wide association studies on self-reported and accelerometer-derived sleep duration, estimated glomerular filtration rate and chronic kidney disease were analysed in total, as well as separately in diabetic and non-diabetic individuals. Inverse variance weighted (IVW) method, weighted median-based method, MR-Egger and MR-Pleiotropy RESidual Sum and Outlier (MR-PRESSO) were applied, as well as the leave-one-out method to rule out the impact of single single-nucleotide polymorphism.

RESULTS

Individuals with genetically longer self-reported sleep duration had a higher chronic kidney disease risk (IVW: β = 0.358, p = 0.047). Furthermore, in non-diabetics, longer self-reported sleep duration was negatively associated with estimated glomerular filtration rate (IVW: β = - 0.024, p = 0.020). Similarly, accelerometer-derived sleep duration was negatively related to estimated glomerular filtration rate in the total population (IVW: β = - 0.019, p = 0.047) and then on-diabetic individuals. No significant association was found between self-reported sleep duration and estimated glomerular filtration rate in the whole population and type-2 diabetes mellitus patients. None of the estimated associations was subjected to a significant level of heterogeneity. MR-PRESSO analysis did not show any chance of outliers for all estimates. The pleiotropy test also indicated low chance of pleiotropy. The leave-one-out method demonstrated that the links were not driven by single-nucleotide polymorphisms.

CONCLUSIONS

For the first time, the present study shed a light on the potential harmful effects of longer sleep duration (measured both objectively and subjectively) on kidney function. This finding was observed in the total population and in non-diabetic individuals, but not in those with diabetes. Further research is needed to elucidate the links between sleep duration, estimated glomerular filtration rate and the risk of chronic kidney disease.

Taking Sleeping Pills and the Risk of Chronic Kidney Disease: A Nationwide Population-Based Retrospective Cohort Study

Background: Sleeping disorder has been associated with chronic kidney disease (CKD); however, the correlation between sleeping pills use and CKD has not been investigated in-depth yet. This study elucidated the potential association of sleeping pill use with the risk of CKD and CKD progression to end-stage renal disease (ESRD) requiring dialysis. Methods: This study was based on a population-based cohort that included 209,755 sleeping pill users among 989,753 individuals. After applying the exclusion criteria, 186,654 sleeping pill users and 373,308 nonusers were enrolled to monitor the occurrence of CKD. Using a cumulative daily dose, we analyzed the types of sleeping pills related to the risk of CKD and ESRD. Propensity score matching and analysis using Cox proportional hazards regression were performed with adjustments for sex, age, and comorbidities. Results: Sleeping pill use was related to increased CKD risk after adjusting for underlying comorbidities (adjusted hazard ratio [aHR] = 1.806, 95% confidence interval [CI]: 1.617-2.105, p < 0.001). With the exception of hyperlipidemia, most comorbidities correlated with an increased risk of CKD. Persistent use of sleeping pills after CKD diagnosis increased the risk of concurrent ESRD (aHR = 7.542; 95% CI: 4.267-10.156; p < 0.001). After the subgroup analysis for sleeping pill use, brotizolam (p = 0.046), chlordiazepoxide (p < 0.001), clonazepam (p < 0.001), diazepam (p < 0.001), dormicum (p < 0.001), estazolam (p < 0.001), fludiazepam (p < 0.001), flunitrazepam (p < 0.001), nitrazepam (p < 0.001), trazodone (p < 0.001), zolpidem (p < 0.001), and zopiclone (p < 0.001) were found to have significant correlation with increased CKD risk. Conclusion: Sleeping pill use was related to an increased risk of CKD and ESRD. Further studies are necessary to corroborate these findings.

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.

Does obstructive sleep apnoea contribute to obesity, hypertension and kidney dysfunction in children? A systematic review protocol

INTRODUCTION

Childhood obstructive sleep apnoea (OSA) is a highly prevalent disorder that may directly contribute to the development of obesity, hypertension and renal injury. Although those associations seem to be clearer in adults, studies in children have revealed conflicting results and updated synthesis of the evidence is lacking. The aim of this systematic review is to summarise the available evidence on the effect of OSA on obesity, systemic blood pressure and kidney function, to help to elucidate whether respiratory interventions to correct OSA would have the potential to improve those outcomes.

METHODS AND ANALYSIS

A systematic literature review search was created by a medical librarian and peer-reviewed by a second librarian prior to running. Ovid Medline, Ovid Embase, CINAHL via EbscoHOST, Wiley Cochrane Library and ProQuest Dissertations and Theses Global were searched on 25 February 2020. Titles and abstracts will be screened by two independent reviewers for inclusion, followed by full-text screening of relevant articles. Studies in children will be included if they report data on OSA and weight, systemic blood pressure or kidney parameters. The extracted data will be combined for analysis and the information subcategorised in groups based on outcome. Risk of bias will be determined using tools specific to study methodology and certainty of the evidence using the Grading of Recommendations, Assessment, Development and Evaluations approach.

ETHICS AND DISSEMINATION

This study will provide essential information for healthcare professionals to better understand the relationship between childhood OSA and changes in body mass index, systemic blood pressure and kidney function indicators. Our findings will be disseminated through conferences and publications. The results of this review may guide the initiation of new strategies and the development of future research studies. This research did not involve human subjects and therefore did not undergo research ethical review.

PROSPERO REGISTRATION NUMBER

CRD42020171186.

Obstructive Sleep Apnea, Other Sleep Characteristics, and Risk of CKD in the Atherosclerosis Risk in Communities Sleep Heart Health Study

BACKGROUND

Obstructive sleep apnea may be associated with development of CKD through hypoxia, inflammation, and oxidative stress. Individuals with this sleep disorder are also at increased risk for established CKD risk factors, including obesity, hypertension, and type 2 diabetes.

METHODS

We examined the association between obstructive sleep apnea, other sleep characteristics, and risk of incident CKD (stage 3 or higher) in 1525 participants (mean age, 62.5 years; 52.4% women) in the Atherosclerosis Risk in Communities (ARIC) study who completed in-home polysomnography assessments. We used the apnea-hypopnea index (events per hour) to define obstructive sleep apnea severity (normal, <5.0; mild, 5.0-14.9; moderate, 15.0-29.9; and severe, ≥30.0) and defined incident CKD (stage 3 or higher) as eGFR<60 ml/min per 1.73 m² and ≥25% decline from baseline, CKD-related hospitalization or death, or ESKD. Cox proportional hazards regression was used to estimate obstructive sleep apnea severity with risk of incident CKD, adjusting for demographics, lifestyle behaviors, and cardiometabolic conditions.

RESULTS

During 19 years (median) of follow-up, 461 CKD events occurred. After adjustment for demographics and lifestyle behaviors, severe obstructive sleep apnea associated with increased risk of CKD (hazard ratio [HR], 1.51; 95% confidence interval [95% CI], 1.08 to 2.10), which was attenuated after adjustment for body mass index (HR, 1.07; 95% CI, 0.75 to 1.52). No other sleep characteristics associated with incident CKD.

CONCLUSIONS

We found a link between obstructive sleep apnea and an elevated risk of stage 3 CKD or higher, but this association was no longer significant after adjusting for obesity, a risk factor for both conditions. Given the high prevalence of obstructive sleep apnea and CKD among adults, further investigation is warranted.

US Trends in Prevalence of Sleep Problems and Associations with Chronic Kidney Disease and Mortality

BACKGROUND

To better understand the relation between sleep problems and CKD, we examined temporal trends in the prevalence of self-reported sleep problems in adults in the United States and their associations with CKD and all-cause mortality.

METHODS

Using data from 27,365 adult participants in five biannual National Health and Examination Surveys (2005-2006 through 2013-2014), we studied five self-reported sleep problems-trouble sleeping, sleep disorder, nocturia (urinating ≥2 times/night), inadequate sleep (<7 hours/night), and excessive sleep (>9 hours/night)-plus a composite index. We conducted three types of analysis: temporal trends in the prevalence of each sleep measure by CKD status, using model-based standardization; cross-sectional analysis of associations between four CKD measures and each sleep measure, using logistic regression; and survival analysis of the association between each sleep measure and mortality, using Cox regression.

RESULTS

The prevalence of trouble sleeping and sleep disorder increased over the five surveys by 4% and 3%, respectively, whereas the other sleep problems remained relatively stable. All sleep problems, except inadequate sleep, were more common during the study period among adults with CKD than without CKD (40% versus 21% for nocturia; 5% versus 2% for excessive sleep; 30% versus 25% for trouble sleeping; 12% versus 8% for sleep disorder). Both eGFR <30 ml/min per 1.73 m² and albuminuria were positively associated with nocturia and excessive sleep. Excessive sleep and nocturia were also associated with higher mortality (adjusted hazard ratio for >9 versus 7-9 hours/night=1.7; 95% CI, 1.3 to 2.1; and for nocturia=1.2; 95% CI, 1.1 to 1.4).

CONCLUSIONS

The high prevalence of sleep problems among persons with CKD and their associations with mortality suggest their potential importance to clinical practice. Future work could examine the health effects of identifying and treating sleep problems in patients with CKD.

Obesity-Related Glomerulopathy: A Latent Change in Obesity Requiring More Attention

BACKGROUND

Obesity has become a major public health problem, and the prevalence of kidney diseases has increased in parallel. Among kidney diseases caused by metabolic disorders, obesity-related glomerulopathy (ORG) is secondary to obesity.

SUMMARY

ORG is mainly caused by glomerular hyperfiltration, dysregulation of hormone and cytokine secretion in adipose tissues, and ectopic lipid accumulation in renal cells. ORG is pathologically characterized by glomerular hypertrophy, with or without focal and segmental glomerulosclerosis. Patients with ORG usually present with proteinuria concomitant with metabolic disorders such as dyslipidemia and hypertension. Weight loss, RAAS inhibitors, and improved insulin resistance can reduce the progression of ORG.

CONCLUSION

ORG is a growing renal pathological change in obese individuals, and a comprehensive understanding of the disease is pivotal to avoid its occurrence and improve quality of life for those with obesity. Key Messages:This review comprehensively describes the characteristics of ORG in pathological changes, clinical manifestations, pathogeneses and treatments.

The association between daily naps and metabolic syndrome: Evidence from a population-based study in the Middle-East

BACKGROUND

Daily naps are a common habit in many Middle Eastern and Asian countries; however, little is known about the association between daily naps and other health consequences, including the presence of metabolic syndrome (MetS).

METHODS

Participants were recruited from the Mashhad stroke and heart atherosclerotic disorders study. We defined MetS according to International Diabetes Federation criteria. Nighttime sleeping hours were categorized into three categories: <6, 6-8, and >8 hours. Using logistic regression models, we analyzed the association between the duration of night-time sleep and daily naps with MetS and its different components.

RESULTS

A total of 9652 individuals were included in the study: 3859 with MetS (40%) and 5793 without MetS (60%), as the control group. Of all, 72% participants had a regular daily nap. Those with daily naps had a higher odd of MetS [Odds ratio:1.19, confidence interval: (1.08-1.33); P < .001]. We also observed significantly higher odds of obesity, central obesity, hypertriglyceridemia, and diabetes or impaired fasting glucose in these subjects. Men sleeping <6 hours per night had a lower odd of MetS. However, we observed higher odds of cardiovascular risk factors in participants sleeping <6 hours, including obesity and diabetes or IFG.

CONCLUSION

Napping is a common habit in middle Eastern countries. Although the cross-sectional design of our study cannot prove causality, we observed a significant association between the presence of MetS and daily naps. The public should be aware of this possibility and be educated about the importance of sleeping patterns.

Association of sleep duration with chronic kidney disease and proteinuria in adults: a systematic review and dose-response meta-analysis

BACKGROUND AND OBJECTIVES

Previous studies have found that sleep duration may be associated with chronic kidney disease (CKD) and proteinuria in adults. However, the correlation remains controversial. In this study, we aimed to assess the effects of sleep duration on CKD and proteinuria.

METHODS

PubMed, EMBASE, and Cochrane Library were searched from their inception up to April 5, 2019 for observational study. The outcomes were CKD and/or proteinuria and the exposure was sleep duration assessed by self-reported questionnaire or interview. Studies were included if they provided risk estimates of effects of sleep duration on patients with CKD or proteinuria. The overall effects were measured by odds ratios (OR) and 95% confidence intervals (CI). Heterogeneity was quantified using Q statistics and the I² statistics. The potential causes of heterogeneity were investigated using sensitivity analysis.

RESULTS

Eleven observational studies with 521,242 individuals were included. The adjusted ORs of CKD in individuals who slept ≤ 6 h/night and ≥ 8 h/night were 1.13 (95% CI, 1.02-1.25; I² = 29%) and 1.14 (95% CI, 1.07-1.22; I²= 0%), respectively. Meanwhile, the adjusted ORs of proteinuria in those who slept ≤ 6 h/night and ≥ 8 h/night were 1.24 (95% CI, 1.06-1.44; I² = 61%) and 1.15 (95% CI, 1.04-1.29; I² = 0%), respectively. Furthermore, a U-shaped relationship was observed between sleep duration and CKD or proteinuria, with the lowest risk at 7 h/night of sleep.

CONCLUSIONS

Both short and long sleep durations are significantly associated with CKD and proteinuria. Our findings suggest curvilinear dose-response associations of sleep duration with CKD and proteinuria.

The effects of depression and age on sleep disturbances in patients with non-dialysis stage 3-5 chronic kidney disease: a single-center study

PURPOSE

Sleep disturbances have a negative impact on the prognosis of chronic kidney disease (CKD). However, information on the prevalence and predictors is limited. This study aimed to evaluate the prevalence and explore clinical factors affecting the quality of sleep in patients with non-dialysis CKD.

METHODS

Participants included 152 adult non-dialysis patients with stage 3-5 CKD. Demographic and clinical data were collected. Sleep quality and depression were assessed using the Pittsburgh Sleep Quality Index (PSQI) and Beck Depression Inventory (BDI), respectively. Sleep disturbances were defined as a PSQI score ≥ 5. Logistic regression was conducted to explore the independent factors of sleep disturbances. Clinical parameters were correlated with BDI scores using linear regression models.

RESULTS

The total prevalence of patients with sleep disturbances was 66.4%. Older age, higher BDI scores, lower estimated glomerular filtration rate (eGFR) changes per month (△eGFR/m) before the study, and lower serum magnesium levels were found in patients with sleep disturbances. BDI scores (odds ratio [OR] 1.224, 95% confidence interval [CI] 1.091-1.373, p = 0.001) and age (OR 1.041, 95% CI 1.013-1.069, p = 0.003) were independent predictors of sleep disturbances. Serum uric acid levels (β - 0.629, 95% CI - 1.244 to - 0.013, p = 0.046), △eGFR/m before the study (β - 0.454, 95% CI - 0.885 to - 0.024, p = 0.039), and daily protein intake (β - 0.052, 95% CI - 0.102 to - 0.002, p = 0.043) were negatively associated with BDI scores.

CONCLUSION

A high overall prevalence of sleep disturbances was found in patients with non-dialysis stage 3-5 CKD. Depression, as a manageable predictor, should be managed, especially in elderly patients.

Sleep apnea and kidney transplant outcomes: findings from a 20-year (1997-2017) historical cohort study

OBJECTIVE/BACKGROUND

A historic cohort single-center study of kidney transplant recipients with graft loss examined the associations between sleep apnea and two transplant outcomes, death with a functioning graft (DWFG), and graft survival time.

PATIENT/METHODS

Adult patients who received transplants and experienced graft failure or DWFG from January 1, 1997 to January 1, 2017 constituted the cohort (n = 322). Data for the study were obtained by merging two secondary data sources: the Organ Procurement and Transplantation Network (OPTN) database and the transplant center's medical records. A Cox regression modeled the association of diagnosed sleep apnea, stratified by year-of transplant surgery, with graft survival time. Using backward elimination, this model was adjusted for recipient age, race/ethnicity, gender, functional status, donor age, and antigen mismatch.

RESULTS

No statistically significant differences were found for proportions of DWFG in those with, versus without, sleep apnea, informing our censoring approach. When examining graft survival time, the Cox regression model was stratified given a sleep apnea and year-of-transplant interaction (p < 0.01, adjusted model). For patients transplanted between 1997 and 2008, sleep apnea was statistically significantly associated with a decreased risk of graft failure or cardiovascular-related DWFG [adjusted Hazard Ratio (aHR) = 0.63, 95%CI, 0.42-0.94]. For patients transplanted between 2009 and 2017, sleep apnea statistically significantly increased the risk of graft failure or cardiovascular-related DWFG (aHR = 2.61, 95%CI, 1.13-6.00).

CONCLUSIONS

In a cohort of transplant recipients with graft loss, sleep apnea increased the risk of graft loss nearly three-fold among patients transplanted between 2009 and 2017. Similar DWFG proportions by sleep apnea presence indicate this risk is likely driven by renal failure, not mortality. Further research on whether treatment of sleep apnea can improve graft survival is warranted.