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

The health-related quality of life among patients on maintenance haemodialysis: Evaluation using the "EQ-5D"

PURPOSE

We conducted a cross-sectional investigation of health-related quality of life (HRQOL) among maintenance haemodialysis (MHD) patients, and determined important predictive factors of HRQOL in these patients.

METHODS

Psychological factors were evaluated with the Hospital Anxiety and Depression Scale (HADS), the Pittsburgh Sleep Quality Index (PSQI) and the General Self-Efficacy Scale (GSES). HRQOL was evaluated with the EQ-5D. Laboratory data (albumin, haemoglobin and C-reactive protein) were collected for medical evaluation. We also collected participants' demographic data, including gender, age, et al. This study was in compliance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist.

RESULTS

The mean EQ-5D score was 0.86 ± 0.12, mean HADS-anxiety score was 5.27 ± 3.41, mean HADS-depression score was 5.29 ± 3.58, mean PSQI score was 7.00 ± 4.23 and mean GSES score was 6.86 ± 2.03. Participants' mean haemoglobin was 108.18 ± 16.45 g/L, mean albumin was 41.80 ± 4.61 g/L and mean C-reactive protein was 8.88 ± 18.50 mg/L. HRQOL was negatively correlated with HADS-anxiety (r = -0.390, p < 0.001), HADS-depression (r = -0.385, p < 0.001), PSQI (r = -0.285, p < 0.001) and C-reactive protein (r = -0.198, p = 0.034). HRQOL was positively correlated with GSES (r = 0.205, p = 0.007). Age (p < 0.001), anxiety (p < 0.001), depression (p = 0.002), and postdialysis unemployment (p < 0.001) were independent risk factors for HRQOL.

CONCLUSION

Different health interventions should be implemented to improve patients' HRQOL.

RELEVANCE TO CLINICAL PRACTICE

The results will provide evidence for establishing healthcare interventions to maintain or improve HRQOL among this patient population.

Association of serum adiponectin level with cystatin C in male patients with obstructive sleep apnea syndrome

PURPOSE

Obstructive sleep apnea syndrome (OSAS) was suggested to exert an effect on renal function. However, the specific mechanism was still unknown. We try to find the association among OSAS, adiponectin, and cystatin C and the effect of adiponectin on renal function in OSAS patients.

METHODS

Seventeen healthy men and seventy-three men which only had OSAS were included in the end. Apnea-hypopnea index (AHI), oxygen desaturation index (ODI), the percentage of total sleep time spent with SpO₂ < 90% (T90%), lowest O₂ saturation (LaSO₂), Epworth Sleepiness Scale (ESS) score, serum adiponectin, and high-sensitive C-reactive protein (hsCRP) were detected in all subjects, and renal function was evaluated with creatinine, cystatin C, and estimated glomerular filtration rate (eGFR).

RESULTS

Demographic data, creatinine, and eGFR did not differ among the studied groups. Decreased serum adiponectin levels were associated with severe OSAS. OSAS patients had a higher hsCRP and cystatin C than those without OSAS. Serum adiponectin levels had a negative association with cystatin C. After adjusted for confounders, adiponectin, hsCRP, and ODI had a significant prediction on the cystatin C (β = - 0.218, p = 0.011; β = 0.226, p = 0.037; and β = 0.231, p = 0.029).

CONCLUSIONS

Decreased serum adiponectin was associated with increased cystatin C in male OSAS patients. These results suggest that serum adiponectin might be a regulatory factor for renal function in OSAS.

Short sleep duration is related to kidney-related biomarkers, but not lipid profile and diet quality in diabetic nephropathy patients

Objectives: Diabetic nephropathy may adversely influence on sleep duration. The quality of diet may also be affected by both sleep duration and diabetes nephropathy. Therefore, lower diet quality in short sleepers-diabetic nephropathy patients might be related to higher metabolic abnormalities. In the present study, we investigated if sleep duration is related to diet quality indices and biochemical markers in diabetic nephropathy patients. Method: This cross-sectional study was conducted among 237 diabetic nephropathy patients, randomly selected from patients attending in the Alzahra University Hospital, Isfahan, Iran. Usual dietary intake was assessed using validated food frequency questionnaire. Diet quality indices (including diet diversity score, dietary energy density, mean adequacy ratio, and nutrient adequacy ratio) were calculated based on standard definitions. Sleep duration was estimated using self-reported nocturnal hours of sleep. Results: Short sleepers (5-6 h) had higher blood urea nitrogen and creatinine compared with those who slept more than 7.5 h (20.26 + 0.23 mg/dl vs. 17.61 + 0.30 mg/dl, P < 0.0001, and 1.98 + 0.27 mg/dl vs. 1.90 + 0.24 mg/dl, P = 0.03, respectively). Serum triglyceride levels were positively correlated with sleep duration (P = 0.02). Diet quality indices were not significantly associated with sleep duration. Conclusion: Higher sleep duration is significantly related to lower kidney-related biomarkers in diabetic nephropathy patients. Diet quality indices were not associated with sleep duration in diabetic nephropathy patients. More longitudinal studies are required to evaluate the associations of sleep duration, diet quality and biochemical markers in diabetic nephropathy patients.

Hydrogen protects against chronic intermittent hypoxia induced renal dysfunction by promoting autophagy and alleviating apoptosis

AIMS

Hydrogen gas (H₂) has a diversity of effects such as anti-apoptotic, anti-inflammatory and anti-oxidative properties. However, molecular mechanism underlying the potential effect of H₂ on chronic intermittent hypoxia (CIH) induced renal injury remains obscure.

MATERIALS AND METHODS

In the present study, adult male Sprague-Dawley rats were randomly allocated into four groups: control (CON) group, CIH group, CIH with H₂ treatment (CIH + H₂) group, and control with H₂ treatment (CON + H₂) group. Oxidative stress, autophagy and endoplasmic reticulum (ER) stress were detected to determine how H₂ affected the renal function of CIH exposed rats.

KEY FINDINGS

We demonstrated that rats who inhale hydrogen gas showed improved renal function, alleviated pathological damage, oxidative stress and apoptosis in CIH rats. Meanwhile, CIH-induced endoplasmic reticulum stress was decreased by H₂ as the expressions of CHOP, caspase-12, and GRP78 were down-regulated. Furthermore, relative higher levels of LC3-II/I ratio and Beclin-1, with decreased expression of p62, were found after H₂ administrated. Inhibition of mTOR may be involved in the upregulation of autophagy by H₂. Finally, increased phosphorylation of p38 and JNK was involved in the CIH-induced pathological process. H₂ could inhibit the activation of p38 and JNK, suggesting H₂ played an active part in resisting renal injury via MAPK.

SIGNIFICANCE

Taken together, our study reveals that H₂ can ameliorate CIH-induced kidney injury by decreasing endoplasmic reticulum stress and activating autophagy through inhibiting oxidative stress-dependent p38 and JNK MAPK activation.

Self-reported snoring is associated with chronic kidney disease independent of metabolic syndrome in middle-aged and elderly Chinese

AIMS/INTRODUCTION

To investigate the correlation between snoring and chronic kidney disease (CKD), and explore whether metabolic syndrome (MetS) plays an important role in this relationship among middle-aged and elderly Chinese.

MATERIALS AND METHODS

The participants included in the present study were categorized into three subgroups based on self-reported snoring frequency (regularly [≥3 times per week], occasionally [between 'regularly' and 'never'] or never [<1 time per month]). An estimated glomerular filtration rate <60 mL/min/1.73 m2 was considered as CKD. We diagnosed MetS based on the 2004 Chinese Diabetes Society criteria. We explored the relationship between snoring and CKD by using multiple logistic regressions.

RESULTS

The frequency of MetS, MetS components and CKD was dramatically higher in regular snorers than in non-snorers and occasional snorers. The odds ratios for MetS and all the MetS elements, except for hyperglycemia, increased progressively with the snoring frequency (P < 0.001). Upon additional adjustment for other MetS components, snoring was not significantly related with hypertension; however, the associations between snoring frequency and overweight/obesity and dyslipidemia became attenuated, but still remained statistically significant (P < 0.01). Interestingly, odds ratios for CKD also increasingly augmented with snoring frequency (P < 0.001). Upon further adjustment for individual MetS components or MetS, regular snoring also resulted in a significantly increased odds ratio for CKD (odds ratio 1.72; P = 0.034) relative to non-snoring.

CONCLUSIONS

Self-reported snoring is closely associated with CKD independent of MetS among middle-aged and elderly Chinese.

Sleep Quality and Sleep Duration with CKD are Associated with Progression to ESKD

BACKGROUND AND OBJECTIVES

Shorter or longer sleep duration and poor sleep quality are risk factors for numerous cardio-metabolic diseases, cardiovascular disease, and mortality in subjects with normal kidney function. The association of sleep duration and sleep quality with health outcomes in patients with CKD remains uncertain.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A 4-year prospective cohort study in 17 nephrology centers in Japan, the CKD Japan Cohort (CKD-JAC) Study, assessed an association of self-reported sleep duration and sleep quality, on the basis of the Pittsburgh Sleep Quality Index (PSQI) questionnaire, with incidence of ESKD in 1601 patients with eGFR 10-59 ml/min per 1.73 m2 using multivariable-adjusted Cox proportional hazards models.

RESULTS

Baseline sleep duration and PSQI global score for the 1601 patients were mean±SD 7.0±1.3 hours and median 4 (interquartile range, 3-7), respectively. Poor sleep quality (PSQI global score ≥6) was common (n=588 [37%]). During a median of 4.0 (2.6-4.3) years of the follow-up period, 282 (18%) patients progressed to ESKD. After adjusting for age, sex, eGFR, urinary albumin excretion, smoking status, body mass index, history of diabetes and cardiovascular disease, systolic BP, blockade of the renin-angiotensin system, use of hypnotics, and Beck depression inventory score, both shorter (≤5 hour) and longer (>8 hour) sleep duration were associated with ESKD (adjusted hazard ratios [95% confidence intervals] for ≤5.0, 5.1-6.0, 6.1-7.0, 7.1-8.0, and ≥8.0 hours were 2.05 [1.31 to3.21], 0.98 [0.67 to 1.44], 1.00 [reference], 1.22 [0.89 to 1.66], and 1.48 [1.01 to 2.16]), suggesting a U-shaped relationship between sleep duration and ESKD. PSQI global score ≥6 was also associated with incidence of ESKD (adjusted hazard ratios [95% confidence intervals] for PSQI global score ≤5 and ≥6 were 1.00 [reference] and 1.33 [1.03 to 1.71]).

CONCLUSIONS

Shorter (≤5 hour) and longer (>8 hour) sleep duration and poor sleep quality (PSQI global score ≥6) were associated with ESKD in patients with CKD.

Sleep duration and risk of end-stage renal disease: the Singapore Chinese Health Study

OBJECTIVES

Although epidemiological evidence suggests that short sleep duration may affect renal function, the influence of long sleep and risk of end-stage renal disease (ESRD) is unclear. We examined the association between sleep duration and risk of ESRD.

METHODS

We investigated sleep duration and ESRD risk in the Singapore Chinese Health Study, a prospective population-based cohort of 63,257 Chinese in Singapore, who were aged 45-74 years at recruitment (1993-1998). Information on daily sleep duration (including naps), diet, medical history and other lifestyle factors was collected at recruitment from in-person interviews. ESRD cases were identified via linkage with the nationwide Singapore Renal Registry through year 2014. We used the Cox proportional hazards regression method to estimate hazard ratio (HR) and 95% confidence interval (CI) of ESRD in relation to sleep duration.

RESULTS

After an average 16.8 years of follow-up, 1143 (1.81%) ESRD cases were documented. Sleep duration had a U-shaped association with risk of ESRD (P for quadratic trend < 0.001). Compared with participants with 7 h/day of sleep, the multivariable adjusted HR (95% CI) of ESRD was 1.43 (1.18-1.74) for short sleep (≤5 h/day) and 1.28 (1.03-1.60) for long sleep duration (≥9 h/day). The increased risk was stronger in participants with more than 10 years of follow-up compared to those with shorter follow-up time, especially for long sleep (P for interaction = 0.003).

CONCLUSIONS

Our findings demonstrated that both short and long sleep durations were associated with a higher risk of ESRD in this Asian population.

Telmisartan attenuates kidney apoptosis and autophagy-related protein expression levels in an intermittent hypoxia mouse model

Purpose

Obstructive sleep apnea (OSA) is associated with renal impairs. As a novel pathophysiological hallmark of OSA, chronic intermittent hypoxia (CIH) enhances apoptosis and autophagy. The present study aims to evaluate the effect of telmisartan on CIH-induced kidney apoptosis and autophagy in a mouse model of OSA.

Materials and methods

Mice were randomly allocated to normoxia, CIH, and CIH+telmisartan groups (n = 12 in each group). The CIH exposure duration was 12 weeks. Mice in the CIH+telmisartan group received telmisartan administration. The terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and western blotting of Bax and cleaved caspase-3 were conducted for evaluating apoptosis in kidney tissue. While the autophagy-related proteins, beclin-1 and LC3, were also observed via western blotting.

Results

The percentage of apoptotic cell in the CIH group was significantly higher than that of normoxia group; meanwhile, Bax and cleaved caspase-3 protein levels were increased in the CIH group than those of normoxia group (all p < 0.05). Compared with the normoxia group, mice in the CIH group had greater autophagy-related proteins (beclin-1 and LC3) expression. When compared to the CIH group, both the renal apoptosis and autophagy in the CIH+telmisartan group were decreased.

Conclusion

The CIH accelerates renal apoptosis and autophagy levels. Telmisartan ameliorating those levels suggests that it might prevent renal impairs from the CIH in OSA patients.

Gender differences in the relationships between chronic kidney disease, asymmetric dimethylarginine, and sleep quality: The HEIJO-KYO cohort

The association between chronic kidney disease (CKD), serum levels of asymmetric dimethylarginine (ADMA), and sleep quality has not been studied in large populations. In this cross-sectional study of 1115 elderly individuals (mean age, 71.9 years), we measured serum levels of ADMA, and objective and subjective sleep quality using actigraphy and a standardized self-reported questionnaire, respectively. Multivariable analysis adjusted for potential confounders revealed that in females, compared with the non-CKD/low-ADMA group (n=312), sleep efficiency was significantly lower in the CKD/high-ADMA group (n=52) by 3.5% for objective sleep quality [95% confidence interval (CI), 1.1-5.9] and by 4.2% (95% CI, 0.3-8.0) for subjective sleep quality but not in the non-CKD/high-ADMA (n=179) and CKD/low-ADMA (n=36) groups. In males, no significant associations between CKD, ADMA levels, and sleep quality were observed. Wake time after sleep onset was significantly longer by 11.3 min (95% CI, 3.0-19.6) for objective sleep quality and by 25.9 min (95% CI, 4.9-46.9) for subjective sleep quality in the CKD/high-ADMA group than in the non-CKD/low-ADMA group in females but not in males. Mediation analysis revealed a significant effect of serum ADMA levels on the association between renal function and parameters of sleep quality among females. In conclusions, both objective and subjective sleep quality were poorer in elderly females with CKD/high-ADMA than in those with non-CKD/low-ADMA, but not in males. Association between CKD and sleep disturbances might be mediated by ADMA levels.

Sleep-Disordered Breathing and Prevalent Albuminuria in Hispanics/Latinos

Introduction

Although sleep-disordered breathing has been found to be associated with higher urine albumin excretion, this association has not been evaluated in Hispanic/Latino populations, which experience a high burden of end-stage renal disease compared with non-Hispanics. We evaluated the association of sleep-disordered breathing with prevalent albuminuria among US Hispanics/Latinos.

Methods

This was a cross-sectional study of baseline data from participants in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), a population-based study that enrolled 16,415 adults in 4 US communities. Sleep-disordered breathing was assessed using a home sleep apnea monitor for overnight recording and was defined using 3 thresholds of the apnea−hypopnea index (AHI; 3% desaturation): ≥5, ≥15, and ≥30. Albuminuria was defined as a urine albumin-to-creatinine ratio of ≥30 mg/g.

Results

There were 12,572 participants with complete data available for analysis. The age- and sex-adjusted prevalence of albuminuria was 9.1%. Mean age was 41 years, and 48% were men. Age- and sex-adjusted prevalence of sleep-disordered breathing was higher among individuals with albuminuria compared with those without albuminuria (36% vs. 25% had AHI ≥5, 18% vs. 9% had AHI ≥15, and 9% vs. 4% had AHI ≥30). In multivariable logistic regression analyses, AHIs ≥5, ≥15, and ≥30 were associated with greater odds of albuminuria compared with those with AHIs <5, <15, and <30 (odds ratio [OR] 1.42, 95% confidence interval [CI]: 1.14−1.76; OR: 1.71, 95% CI: 1.33−2.20; and OR 1.93, 95% CI 1.34−2.79), respectively. This association varied by Hispanic/Latino background group.

Conclusion

In US Hispanic/Latinos, sleep-disordered breathing was independently associated with higher odds of prevalent albuminuria.

Sleep Duration and Health-Related Quality of Life in Predialysis CKD

BACKGROUND AND OBJECTIVES

Sleep duration has been associated with cardiometabolic risk and mortality. The health-related quality of life represents a patient's comprehensive perception of health and is accepted as a health outcome. We examined the relationship between sleep duration and health-related quality of life in predialysis CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this cross-sectional study, data from 1910 adults with CKD enrolled in the Korean Cohort Study for Outcome in Patients with CKD were analyzed. Health-related quality of life was assessed with the physical component summary and mental component summary of the Short Form-36 Health Survey. Low health-related quality of life was defined as a Short Form-36 Health Survey score >1 SD below the mean. Using a generalized additive model and multivariable logistic regression analysis, the relationship between self-reported sleep duration and health-related quality of life was examined.

RESULTS

Seven-hour sleepers showed the highest health-related quality of life. We found an inverted U-shaped relationship between sleep duration and health-related quality of life as analyzed by a generalized additive model. In multivariable logistic analysis, short sleepers (≤5 h/d) had lower health-related quality of life (odds ratio, 3.23; 95% confidence interval, 1.86 to 5.60 for the physical component summary; odds ratio, 2.37; 95% confidence interval, 1.43 to 3.94 for the mental component summary), and long sleepers (≥9 h/d) had lower health-related quality of life (odds ratio, 2.80; 95% confidence interval, 1.55 to 5.03 for the physical component summary; odds ratio, 2.08; 95% confidence interval, 1.20 to 3.60 for the mental component summary) compared with 7-hour sleepers. Sleep duration had a significant U-shaped association with low health-related quality of life.

CONCLUSIONS

These findings suggest that short or long sleep duration is independently associated with low health-related quality of life in adults with CKD.

Effect of Sleep-Disordered Breathing on Albuminuria in 273 Patients With Type 2 Diabetes

STUDY OBJECTIVES

Sleep-disordered breathing (SDB) can induce hyperglycemia, hypertension, and oxidative stress, conditions that are known to cause kidney damage. Therefore, SDB may exacerbate albuminuria, which is an established marker of early-stage kidney damage in patients with type 2 diabetes mellitus (T2DM). The association between SDB and albuminuria in patients with T2DM was investigated in this study.

METHODS

This cross-sectional study included 273 patients with T2DM who underwent portable sleep testing and measurement of urine albumin to creatinine ratio (UACR). The association between the severity of SDB and albuminuria was investigated. Patients were divided into three groups according to the respiratory event index (REI): the no or mild group (REI < 15 events/h), moderate (REI 15 to < 30 events/h), and severe (REI ≥ 30 events/h). Albuminuria was defined as UACR ≥ 3.4 mg/mmol creatinine. Logistic regression analysis for albuminuria included the categorical REI as the independent variable.

RESULTS

The median (interquartile range) REI of all patients (age 57.9 ± 11.9 years, mean ± standard deviation, male sex 81.7%, body mass index 26.7 [24.2-29.5] kg/m², estimated glomerular filtration rate 82 [65-97] mL/min/1.73 m²) was 13.0 (7.0-24.2) events/h. The REI, as a categorical variable, was significantly associated with albuminuria after adjustment for other risk factors for albuminuria; REI 15 to < 30 events/h: odds ratio (OR) 3.35, 95% confidence interval (95% CI), 1.68-6.67, P < .001; REI ≥ 30: OR 8.52, 95% CI, 3.52-20.63, P < .001). In addition, the natural logarithm-transformed REI of all patients also correlated significantly with albuminuria.

CONCLUSIONS

The severity of SDB is associated with albuminuria in patients with T2DM.

U-shaped association between sleep duration and urinary albumin excretion in Korean adults: 2011-2014 Korea National Health and Nutrition Examination Survey

Although sleep duration has been extensively studied in metabolic diseases, few studies have investigated the impact of sleep duration on chronic kidney disease. The aim of this study was to examine the relationship between sleep duration and albuminuria in the general population. Among 24,948 adults who participated in the 2011–2014 KNHANES, a total of 19,994 subjects were included in this analysis. Subjects were categorized into the following five groups according to self-reported sleep duration: less than 5 h, 6 h, 7 h, 8 h, and more than 9 h. The association between sleep duration and urinary albumin-creatinine ratio (UACR) was examined cross-sectionally. Subjects with both short and long sleep durations were significantly associated with higher UACR levels and higher proportions of patients with microalbuminuria (30–299 mg/g) and macroalbuminuria (≥300 mg/g) compared to those with a sleep duration of 7 hours. The U-shaped association between sleep duration and UACR remained significant even after adjustment for potential confounders, including age, sex, body mass index, smoking, alcohol, education, income, exercise, estimated glomerular filtration rate, diabetes mellitus, hypertension and hypercholesterolemia. The U-shaped association is more evident in the subgroup aged 65 or older, or in female subjects. Our findings suggest that both short and long sleep durations have a U-shaped association with UACR levels in the general population, independent of potential confounders.

The effects of short sleep duration on proteinuria and chronic kidney disease: a systematic review and meta-analysis

Background

The risks of proteinuria and chronic kidney disease (CKD) in adults who regularly have short sleep duration (short sleepers) are controversial. The aim of this meta-analysis was to assess the effects of short sleep duration on proteinuria and CKD.

Methods

A literature search was conducted using MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews from the inception of the databases through November 2015. Studies that reported relative risks, odd ratios or hazard ratios comparing the risks of proteinuria and CKD in short sleepers were included. Pooled risk ratios (RR) and 95% confidence intervals (CI) were computed utilizing a random-effect, generic inverse variance method.

Results

Six observational studies with 252 075 individuals and three observational studies with 37 197 individuals were included in the analyses to assess the risks of CKD and proteinuria in short sleepers, respectively. The pooled RR of CKD in short sleepers was 1.51 (95% CI, 0.99-2.55). When meta-analysis was restricted only to studies with adjusted analysis for confounders assessing the risk of CKD in short sleepers, the pooled RR of CKD was 1.54 (95% CI, 0.80-2.95). The pooled RR of proteinuria in short sleepers was 1.47 (95% CI, 1.26-1.72).

Conclusions

Despite the lack of significant association between short sleep duration and CKD, our meta-analysis suggests a potential association between short sleep duration and proteinuria, a surrogate marker for kidney disease progression. Future study is required to investigate if reversal of short sleep helps reduce proteinuria.

Sleep Duration and Diabetic Kidney Disease

Aims: Abnormally short or long durations of sleep have been proposed as a risk factors for diabetes and its micro- and macro-vascular complications. However, the relationship between sleep duration and diabetic kidney disease (DKD) has not been well-characterized. Thus, we aimed to examine the association of sleep duration with DKD in two Asian populations. Methods: We included 1,258 persons (Malay, n = 403; Indian, n = 855) aged 40-80 years with diabetes from a population-based cross-sectional sample from Singapore. DKD was defined by low estimated glomerular filtration rate (eGFR <60 mL/min/1.73 m²) and albuminuria (urinary albumin-to-creatinine ratio ≥30 mg/g, only measured in Indian participants). Self-reported habitual sleep duration was categorized into 4 categories: very short (<5 h), short (5-6.9 h), normal (7-8 h) and long (>8 h). The associations of sleep duration with low eGFR and albuminuria were analyzed using multivariable logistic regression models adjusted for multiple potential confounders (including classic risk factors such as HbA1c and hypertension). Results: In total, 268 (21.3%) participants had low eGFR, and 271 (34.7% in Indians) had albuminuria. The number (%) of individuals with very short, short, normal, and long durations of sleep were 117 (9.3%), 629 (50.0%), 429 (34.1%), and 83 (6.6%), respectively. Long sleep duration was associated with a higher odds of renal insufficiency compared to normal sleep duration (OR [95% CI]: 2.31 [1.27-4.19]) on multivariable analysis. Similarly, both long and very short durations of sleep were associated with higher odds of albuminuria (OR [95%]: 2.44 [1.36, 4.38] and 2.37 [1.25, 4.50], respectively) in Indian participants (where data on albuminuria were available). Conclusions: Our study suggests that abnormally short or long durations of sleep were associated with DKD, manifesting as either a reduced eGFR or increased albuminuria. However, further longitudinal data would be required for confirmation.

The Relationship between Diabetes-Related Complications and Obstructive Sleep Apnea in Type 2 Diabetes

This study explored the relationship between obstructive sleep apnea (OSA) and the presence of any diabetes-related complications in type 2 diabetes and whether this was mediated by hypertension. Secondly, the relationship between OSA severity and estimated glomerular filtration rate (eGFR) was investigated. A total of 131 patients participated. OSA was diagnosed using a home monitor, and severity was measured by apnea-hypopnea index (AHI) and oxygen desaturation index (ODI). OSA was found in 75.6% of the participants, 40.5% with moderate-to-severe degree. Any diabetes-related complications (retinopathy, neuropathy, nephropathy, or coronary artery disease) were present in 55.5%, and 70.2% of the participants had hypertension. Mediation analysis indicated that, compared to those with mild or no OSA, those with moderate-to-severe OSA were 3.05 times more likely to have any diabetes-related complications and that this relationship was mediated by the presence of hypertension. After adjusting for confounders, ODI (B = -0.036, p = 0.041), but not AHI, was significantly associated with lower eGFR. In conclusion, moderate-to-severe OSA was related to the presence of any diabetes-related complications in type 2 diabetes, and the relationship was mediated by hypertension. The severity of intermittent hypoxia was associated with lower eGFR. Whether OSA treatment will delay or reduce diabetes-related complications should be investigated.

The association of obstructive sleep apnea and renal outcomes-a systematic review and meta-analysis

BACKGROUND

The aim of this systematic review and meta-analysis was to summarize the association of obstructive sleep apnea (OSA) with renal outcome.

METHODS

Our study followed the PRISMA guidelines. Two independent reviewers searched for relevant articles in the databases of Pubmed, the Web of Science and CENTRAL, and conducted study selection and quality assessment. A random-effect model was used to estimate the effects.

RESULTS

total of 1240 articles were initially identified (Pubmed = 568, Web of Science = 640, CENTRAL = 32). After removal of duplicate articles (n = 415) and irrelevant articles (n = 788), 37 were selected for full-text review, and 18 were finally included in the analysis. Overall, patients diagnosed with OSA were found to have a higher odds ratio (OR) of a poorer renal outcome, with a pooled OR of 1.77 (95% C.I.: 1.37–2.29). The significant association between OSA and a poorer renal outcome was not affected by the medical condition of diabetes mellitus (DM). In addition, we found that OSA was consistently associated with higher albuminuria/proteinuria and a lower estimated glomerular filtration rate (eGFR), with a pooled OR of 1.84 (95% C.I.: 1.24–2.73) and 1.60 (95% C.I.: 1.19–2.16), respectively. A greater OSA severity was also found to be related to a higher OR, with a mild group OR of 1.45 (95% C.I.: 1.19–1.77) and a moderate and severe group OR of 2.39 (95% C.I.: 1.96–2.90).

CONCLUSIONS

Our study demonstrated that OSA is significantly associated with poorer renal function.

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

Physiological evidence suggests that sleep modulates kidney function. Our objective was to examine the cross-sectional association between kidney function and objectively-estimated habitual sleep duration, quality and timing in a cohort of patients with mild to moderate chronic kidney disease. This study involved two US clinical centers of the Chronic Renal Insufficiency Cohort (CRIC) study, including 432 participants in a CRIC ancillary sleep study. Habitual sleep duration, quality and timing were measured using wrist actigraphy for 5-7 days. Validated sleep questionnaires assessed subjective sleep quality, daytime sleepiness and risk of sleep apnea. Kidney function was assessed with the estimated glomerular filtration rate using the Chronic Kidney Disease Epidemiology Collaboration equation, and the urinary protein to creatinine ratio. Lower estimated glomerular filtration rate was associated with shorter sleep duration (-1.1 mL min^-1  1.73 m^-2 per hour less sleep, P = 0.03), greater sleep fragmentation (-2.6 mL min^-1  1.73 m^-2 per 10% higher fragmentation, P < 0.001) and later timing of sleep (-0.9 mL min^-1  1.73 m^-2 per hour later, P = 0.05). Higher protein to creatinine ratio was also associated with greater sleep fragmentation (approximately 28% higher per 10% higher fragmentation, P < 0.001). Subjective sleep quality, sleepiness and persistent snoring were not associated with estimated glomerular filtration rate or protein to creatinine ratio. Thus, worse objective sleep quality was associated with lower estimated glomerular filtration rate and higher protein to creatinine ratio. Shorter sleep duration and later sleep timing were also associated with lower estimated glomerular filtration rate. Physicians treating patients with chronic kidney disease should consider inquiring about sleep and possibly sending for clinical sleep assessment. Longitudinal and interventional trials are needed to understand causal direction.

Home-based versus center-based aerobic exercise on cardiopulmonary performance, physical function, quality of life and quality of sleep of overweight patients with chronic kidney disease

BACKGROUND

The association between chronic kidney disease (CKD) and obesity can decrease the patients' cardiopulmonary capacity, physical functioning and quality of life. The search for effective and practical alternative methods of exercise to engage patients in training programs is of great importance. Therefore, we aimed to compare the effects of home-based versus center-based aerobic exercise on the cardiopulmonary and functional capacities, quality of life and quality of sleep of overweight non-dialysis-dependent patients with CKD (NDD-CKD).

METHODS

Forty sedentary overweight patients CKD stages 3 and 4 were randomly assigned to an exercise group [home-based group (n = 12) or center-based exercise group (n = 13)] or to a control group (n = 15) that did not perform any exercise. Cardiopulmonary exercise test, functional capacity tests, quality of life, quality of sleep and clinical parameters were assessed at baseline, 12 and 24 weeks.

RESULTS

The VO_2peak and all cardiopulmonary parameters evaluated were similarly improved (p < 0.05) after 12 and 24 weeks in both exercise groups. The functional capacity tests improved during the follow-up in the home-based group (p < 0.05) and reached values similar to those obtained in the center-based group. The benefits achieved in both exercise groups were also reflected in improvement of quality of life and sleep (p < 0.05). No differences were observed between the exercise groups, and no changes in any of the parameters investigated were found in the control group.

CONCLUSION

Home-based aerobic training was as effective as center-based training in improving the physical and functional capabilities, quality of life and sleep in overweight NDD-CKD patients.

Sleep and CKD in Chinese Adults: A Cross-Sectional Study

BACKGROUND AND OBJECTIVES

To assess the association between self-reported sleep duration and quality and odds of having CKD in Chinese adults on the basis of a community study.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this cross-sectional study, we included 11,040 Chinese adults who participated in an ongoing prospective study, the Kailuan cohort. Survey questionnaire items addressed insomnia, daytime sleepiness, snoring, and sleep duration during their 2012 interview. Overall sleep quality was evaluated by summarizing these four sleep parameters. Fasting blood samples and single random midstream morning urine samples were collected in 2012 and analyzed for serum creatinine and proteinuria. CKD was defined by eGFR<60 ml/min per 1.73 m2 or proteinuria >300 mg/dl. We also examined those at high or very high risk of having CKD, on the basis of the Kidney Disease Improving Global Outcomes recommendations. The association between sleep quality and CKD was assessed using logistic regression model.

RESULTS

Worse overall sleep quality was associated with higher likelihood of being high or very high risk for CKD (multiadjusted odds ratio, 2.69; 95% confidence interval, 1.30 to 5.59 comparing two extreme categories; P trend <0.01), but not overall CKD (multiadjusted odds ratio, 1.58; 95% confidence interval, 0.89 to 2.80 comparing two extreme categories; P trend =0.46), after adjusting for potential confounders. Specifically, individuals with worse sleep quality were more likely to have proteinuria (multiadjusted odds ratio, 1.95; 95% confidence interval, 1.03 to 3.67 comparing two extreme categories; P trend =0.02), rather than lower eGFR level (multiadjusted mean eGFR levels were 96.4 and 93.6 ml/min per 1.73 m2 in the two extreme sleep categories, respectively; P trend =0.13). However, there was no statistically significant association between individual sleep parameters and CKD status.

CONCLUSIONS

Worse overall sleep quality was associated with higher odds of being high or very high risk for CKD and proteinuria in Chinese adults.

Association of Sleep Duration, Symptoms, and Disorders with Mortality in Adults with Chronic Kidney Disease

INTRODUCTION

In general populations, short and long sleep duration, poor sleep quality and sleep disorders have been associated with increased risk of death. We evaluated these associations in individuals with chronic kidney disease (CKD).

METHODS

Prospective cohort study of 1,452 National Health and Nutrition Examination Survey (NHANES) 2005-2008 participants with CKD. CKD was defined by estimated glomerular filtration rate <60 ml/min/1.73m² or urine albumin-to-creatinine ratio ≥30 mg/g. Sleep duration, sleep symptoms (difficulty falling asleep, difficulty staying asleep, daytime sleepiness and non-restorative sleep), and sleep disorders (restless legs syndrome and sleep apnea) were self-reported. Vital status was determined using NHANES mortality linkage through December 2011.

RESULTS

Mean age was 61 years, 58% were women, and 75% non-Hispanic white. During 4.4 years of median follow-up, we observed 234 deaths of which 75 were due to cardiovascular causes. In multivariable analyses, compared with individuals who reported 7-8 hours of sleep, HR (95% CI) for all-cause mortality for sleep duration <7 hours and >8 hours were 1.50 (1.08-2.10) and 1.36 (0.89-2.08), respectively. The corresponding HR (95%CI) for cardiovascular mortality were 1.56 (0.72-3.37) and 1.56 (0.66-3.65). Non-restorative sleep and restless legs syndrome were associated with increased risk for all-cause mortality (1.63 [1.13-2.35], and 1.69 [1.04-275], respectively).

CONCLUSION

In adults with CKD, short sleep duration, nonrestorative sleep and restless legs syndrome are associated with increased risk of death. These findings underscore the importance of promoting adequate sleep in patients with CKD, and the need for future studies evaluating the impact of sleep interventions in this population.

Sleep duration and quality in relation to chronic kidney disease and glomerular hyperfiltration in healthy men and women

Background

It is unclear whether sleep duration and quality are associated with chronic kidney disease (CKD) and glomerular hyperfiltration. The aim of this study was to examine the association of sleep duration and quality with CKD and glomerular hyperfiltration in young and middle-aged adults.

Methods

We conducted a cross-sectional study of men and women who underwent a health checkup examination, including assessment of sleep duration and quality (n = 241,607). Chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate (eGFR) less than 60 ml/min/1.73 m², and glomerular hyperfiltration was defined as eGFR above the age-/sex-specific 95^th percentile.

Results

In a multinomial logistic regression analysis adjusting for relevant confounders, the adjusted prevalence ratios for CKD (95% confidence interval) comparing sleep durations of ≤ 5, 6, 8, and 9 hours with 7 hours were 1.22 (0.95–1.55), 0.93 (0.75–1.14), 0.97 (0.75–1.26), and 1.56 (1.06–2.30) in men and 0.98 (0.68–1.43), 1.03 (0.72–1.46), 1.39 (0.97–2.00), and 1.31 (0.78–2.22) in women, respectively. The corresponding prevalence ratios (95% confidence interval) for glomerular hyperfiltration were 1.00 (0.93–1.08), 0.97 (0.91–1.03), 1.03 (0.94–1.13), and 1.39 (1.13–1.72) in men and 1.04 (0.95–1.14), 0.96 (0.90–1.04), 1.11 (1.02–1.20), and 1.28 (1.14–1.45) in women, respectively. Poor subjective sleep quality was associated with glomerular hyperfiltration in men and women.

Conclusion

In this large study of young and middle-aged adults, we found that long sleep duration was associated with CKD and glomerular hyperfiltration. Additionally, poor subjective sleep quality was associated with increased prevalence of glomerular hyperfiltration, suggesting the importance of adequate quantity and quality of sleep for kidney function.

The Renal Pathology of Obesity

Obesity causes various structural, hemodynamic, and metabolic alterations in the kidney. Most of these are likely to be compensatory responses to the systemic increase in metabolic demand that is seen with obesity. In some cases, however, renal injury becomes clinically apparent as a result of compensatory failure. Obesity-related glomerulopathy is the best known of such disease states. Factors that may sensitize obese individuals to renal compensatory failure and associated injury include the severity and number of obesity-associated conditions or complications, including components of metabolic syndrome, and the mismatch of body size to nephron mass, due to nephron reductions of congenital or acquired origin.

Sleep quality and risk factors of atherosclerosis in predialysis chronic kidney disease

INTRODUCTION

Chronic kidney disease (CKD) patients have more frequent sleep disorders and cardiovascular disease than normals. Since arterial stiffness as a risk factor of atherosclerosis can be evaluated with pulse wave velocity (PWV), we aimed to investigate the prevalance of sleep quality (SQ) and the relationship between SQ and risk factors of atherosclerosis and whether there is a relationship between SQ and PWV (the indicator of arterial stiffness) in predialysis CKD patients.

METHODS

This cross-sectional study was carried out in CKD patients followed at the Nephrology Department in Konya, Turkey, between November 2014 and March 2015. A total of 484 CKD patients were screened. Of the 484 patients, 285 patients were excluded. The remaining 199 CKD patients without cardiovascular disease at stage 3, 4, and 5 (predialysis) were included in the final study. The SQ of the patients was evaluated by the Pittsburgh Sleep Quality Index (PSQI). PWV was measured by using a single-cuff arteriography device (Mobil-O-Graph PWA, a model pulse wave analysis device; IEM).

RESULTS

A total of 199 predialysis CKD patients were included in the study, 73 of whom (36.7 %) were 'poor sleepers' (global PSQI &gt;5). Patients with poor SQ were older than those with good SQ (p = 0.077). SQ was worse in female patients compered to male patients (p = 0.001). SQ was worse in obese patients. As laboratory parameters, serum phosphorus, LDL cholesterol, and triglycerides levels correlated positively with SQ (respectively; r = 0.245, p&amp;0.001; r = 0.142, p = 0.049; r = 0.142, p = 0.048). The indicator of arterial stiffness, PWV, was higher in patients with poor SQ (p = 0.033). Hyperphosphatemia and female gender are determined as risk factors for poor SQ in multivariate analysis (p = 0.049, ExpB = 1.477; p = 0.009, ExpB = 0,429, respectively).

CONCLUSIONS

Our study showed for the first time that there is a relationship between SQ and risk factors of atherosclerosis in predialysis CKD patients.

Angiotensin-(1-7) relieved renal injury induced by chronic intermittent hypoxia in rats by reducing inflammation, oxidative stress and fibrosis

We aimed to study the renal injury and hypertension induced by chronic intermittent hypoxia (CIH) and the protective effects mediated by angiotensin 1-7 [Ang(1-7)]. We randomly assigned 32 male Sprague-Dawley rats (body weight 180-200 g) to normoxia control, CIH, Ang(1-7)-treated normoxia, and Ang(1-7)-treated CIH groups. Systolic blood pressure (SBP) was monitored at the start and end of each week. Renal sympathetic nerve activity (RSNA) was recorded. CTGF and TGF-β were detected by immunohistochemistry and western blotting. Tissue parameters of oxidative stress were also determined. In addition, renal levels of interleukin-6, tumor necrosis factor-α, nitrotyrosine, and hypoxia-inducible factor-1α were determined by immunohistochemistry, immunoblotting, and ELISA. TUNEL assay results and cleaved caspase 3 and 12 were also determined. Ang(1-7) induced a reduction in SBP together with a restoration of RSNA in the rat model of CIH. Ang(1-7) treatment also suppressed the production of reactive oxygen species, reduced renal tissue inflammation, ameliorated mesangial expansion, and decreased renal fibrosis. Thus, Ang(1-7) treatment exerted renoprotective effects on CIH-induced renal injury and was associated with a reduction of oxidative stress, inflammation and fibrosis. Ang(1-7) might therefore represent a promising therapy for obstructive sleep apnea-related hypertension and renal injury.

Association of diabetic vascular complications with poor sleep complaints

BACKGROUND

Literatures reported that poor sleep complaints were associated with a great deal of health outcomes. However, there are few studies on the association of poor sleep complaints with diabetic vascular complications.

METHODS

Aiming on the association, a cross-sectional survey was conducted among 1220 diabetic patients in this study. Poor sleep complaints were composed of difficulty falling asleep, early final awakening, short sleep and long sleep. The diabetic vascular complications involved in the study were diagnosed according to the Standards of Medical Care in Diabetes (ADA 2016).

RESULTS

Our findings indicated that short sleep remained independently associated with diabetic kidney disease (DKD) (OR > 1, P < 0.05) after the adjustments; long sleep independently associated with diabetic retinopathy (DR) (OR > 1, P < 0.05); early final awakening and short sleep independently associated with cardiovascular disease (OR > 1, P < 0.05); short sleep independently associated with peripheral arterial disease (OR > 1, P < 0.05); there was no association between poor sleep complaints and neuropathy (P > 0.05).

CONCLUSIONS

The study suggests that the poor sleep complaints were distinguishably associated with diabetic vascular complications. Clinicians should take poor sleep complaints into account in diabetes treatment.

Cystatin C Levels in Middle-Aged Patients with Obstructive Sleep Apnea Syndrome

Background. Obstructive sleep apnea syndrome (OSAS) is associated with systemic inflammation and increased risk of cardiovascular and chronic kidney disease. Cystatin C (Cyst C) is a novel biomarker of both latent renal damage and cardiovascular disease. Aim of the study was to measure serum levels of Cyst C, as well as IL-8 and CRP, in otherwise healthy OSAS patients. Methods. 84 individuals examined with polysomnography for OSAS symptoms without known comorbidities were prospectively recruited. Results. According to apnea hypopnea index (AHI) subjects were divided in two groups: OSAS group (AHI > 5/hour, n = 64) and controls (AHI < 5/hour, n = 20), which were age- and BMI-matched. Cyst C levels were higher in OSAS patients versus controls (1176.13 ± 351.33 versus 938.60 ± 245.83 ng/mL, resp.; p = 0.017) while serum IL-8 and CRP levels did not differ significantly. Positive correlation was found between Cyst C levels and respiratory disturbance index (RDI) (r = 0.240, p = 0.039) and percentage of time with oxygen saturation <90% (r = 0.290, p = 0.02) and negative correlation was found between Cyst C levels and average oxygen saturation during sleep (r = -0.291, p = 0.012). After adjustment for age and BMI, RDI was the only independent predictor of Cyst C levels (β = 0.256, p = 0.039). Conclusion. Cyst C serum levels are increased in OSAS patients without comorbidities, suggesting an increased renal and cardiovascular disease risk.

Simple obstructive sleep apnea patients without hypertension or diabetes accelerate kidney dysfunction: a population follow-up cohort study from Taiwan

Backgrounds

Obstructive sleep apnea (OSA) is common in patients on hemodialysis, but its correlation with chronic kidney disease (CKD) is not clear. We aimed to clarify the relationship between OSA without hypertension or diabetes and incidence of CKD in Taiwan.

Methods

This population-based cohort study consisted of patients with newly diagnosed OSA between 2000 and 2009. The comparison cohort was matched for age, sex, diabetes mellitus, and hypertension. All subjects previously diagnosed with acute or chronic kidney disease were excluded. The primary end point was newly diagnosed CKD.

Results

We identified 6866 subjects with OSA during the 10-year study period. The median duration until development of CKD in the OSA cohort was 3.2 years, 2.5 months earlier than that in the non-OSA cohort. After exclusion of hypertension and diabetes, 4319 OSA patients was identified and the hazard ratio (HR) of CKD with OSA was 1.37 (95 % confidence interval [CI], 1.05–1.77; p = 0.019). In the subgroup analysis, an increased incidence of CKD in OSA was observed in women (HR, 1.41; 95 % CI, 1.12–1.78; p = 0.0036).

Conclusions

This longitudinal population-based cohort study provides evidence that patients with OSA even without diabetes or hypertension are at higher risk of developing CKD over the next 3 years and nearly 2.5 months earlier than the non-OSA cohort, particularly women.

Poor sleep quality is responsible for the nondipper pattern in hypertensive but not in normotensive chronic kidney disease patients

AIM

This study was designed to evaluate the relationship between sleep quality and hypertension and to determine if there was an association between nondipper blood pressure (BP) and sleep quality in chronic kidney disease (CKD) patients.

METHODS

A total of 775 pre-dialysis CKD patients (314 normal BP patients, 461 hypertension patients) defined as dippers or nondippers by ambulatory BP monitoring were recruited for this study. Demographics and clinical correlates were collected, including body mass index, estimated glomerular filtration rate (eGFR) and other measures. Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI).

RESULTS

A total of 185 (58.9%) patients with normal BP and 341 (74.0%) hypertensive patients had a nondipper BP pattern. The hypertension group had a higher prevalence of the nondipper BP pattern, smoking, alcohol intake and diabetes mellitus (DM) and lower eGFR levels and poorer sleep quality than the normal BP group. Patients with the nondipper BP pattern had lower haemoglobin, worse renal function and poorer sleep quality when compared with hypertensive CKD patients with the dipping BP pattern. PSQI scores were significantly associated with the rate of nocturnal BP decline (P < 0.05) in the hypertension group but not in the normal BP group. Poor sleep quality was an independent factor affecting BP pattern in hypertensive CKD patients using multivariate linear and logistic regression analyses. There was no association between sleep quality and hypertension in CKD patients after multivariate logistic regression analyses.

CONCLUSION

Poor sleep quality, which is commonly observed in pre-dialysis CKD patients, is an independent associated factor of the nondipper BP pattern in hypertensive CKD patients. No association was found between poor sleep and nondipper BP in normotensive patients.

Sleep Characteristics in Early Stages of Chronic Kidney Disease in the HypnoLaus Cohort

STUDY OBJECTIVES

To evaluate the association between early stages of chronic kidney disease (CKD) and sleep disordered breathing (SDB), restless legs syndrome (RLS), and subjective and objective sleep quality (SQ).

METHODS

Cross-sectional analysis of a general population-based cohort (HypnoLaus). 1,760 adults (862 men, 898 women; age 59.3 (± 11.4) y) underwent complete polysomnography at home.

RESULTS

8.2% of participants had mild CKD (stage 1-2, estimated glomerular filtration rate [eGFR] ≥ 60 mL/min/1.73 m(2) with albuminuria) and 7.8% moderate CKD (stage 3, eGFR 30-60 mL/min/1.73 m(2)). 37.3% of our sample had moderate-to-severe SDB (apnea-hypopnea index [AHI] ≥ 15/h) and 15.3% had severe SDB (AHI ≥ 30/h). SDB prevalence was positively associated with CKD stages and negatively with eGFR. In multivariate analysis, age, male sex, and body mass index were independently associated with SDB (all P < 0.001), but kidney function was not. The prevalence of RLS was 17.5%, without difference between CKD stages. Periodic leg movements index (PLMI) was independently associated with CKD stages. Subjective and objective SQ decreased and the use of sleep medication was more frequent with declining kidney function. Older age, female sex, and the severity of SDB were the strongest predictors of poor SQ in multivariate regression analysis but CKD stage was also independently associated with reduced objective SQ.

CONCLUSIONS

Patients with early stages of CKD have impaired SQ, use more hypnotic drugs, and have an increased prevalence of SDB and PLM. After controlling for confounders, objective SQ and PLMI were still independently associated with declining kidney function.

Association of short sleep duration and rapid decline in renal function

The kidney is influenced by circadian rhythms and is entrained to the sleep-wake cycle allowing anticipation of the metabolic and physiological demands of the kidney throughout a 24-hour cycle. Although sleep disruption has been studied extensively in cardiovascular and metabolic disease, its association with chronic kidney disease has not been shown. We examined this in a prospective cohort study of 4238 participants from the Nurses' Health Study and analyzed the association of self-reported sleep duration with decline in renal function over an 11-year period (1989 to 2000). Individuals who reported shorter sleep duration were more likely to experience a rapid decline in estimated glomerular filtration rate (30% or more). Compared with sleeping 7 to 8 hours per night, the adjusted odds ratios for a rapid decline in renal function were a significant 1.79 (95% CI, 1.06-3.03) for 5 hours or less sleep per night, a significant 1.31 (95% CI, 1.01-1.71) for 6 hours sleep per night, but an insignificant 0.88 (95% CI, 0.50-1.57) for 9 or more hours sleep per night. Similarly, there was a significant trend in the adjusted annualized decline in estimated glomerular filtration rate of 1.2 ml/min/1.73 m(2)/year, 0.9 ml/min/1.73 m(2)/year, 0.8 ml/min/1.73 m(2)/year, and 0.8 ml/min/1.73 m(2)/year for individuals sleeping 5 hours or less per night, 6 hours per night, 7 to 8 hours per night, and 9 hours or more per night, respectively. Thus, shorter sleep duration is prospectively and independently associated with faster decline in renal function.

Nonapnea Sleep Disorders and the Risk of Acute Kidney Injury: A Nationwide Population-Based Study

Nonapnea sleep disorders (NASDs) and associated problems, which are highly prevalent in patients with kidney diseases, are associated with unfavorable medical sequelae. Nonetheless, whether NASDs are associated with acute kidney injury (AKI) development has not been thoroughly analyzed. We examined the association between NASD and AKI. We conducted a population-based study by using 1,000,000 representative data from the Taiwan National Health Insurance Research Database for the period from January 1, 2000, to December 31, 2010. We studied the incidence and risk of AKI in 9178 newly diagnosed NASD patients compared with 27,534 people without NASD matched according to age, sex, index year, urbanization level, region of residence, and monthly income at a 1:3 ratio. The NASD cohort had an adjusted hazard ratio (hazard ratio [HR]; 95% confidence interval [CI] = 1.15-2.63) of subsequent AKI 1.74-fold higher than that of the control cohort. Older age and type 2 diabetes mellitus were significantly associated with an increased risk of AKI (P < 0.05). Among different types of NASDs, patients with insomnia had a 120% increased risk of developing AKI (95% CI = 1.38-3.51; P = 0.001), whereas patients with other sleep disorders had a 127% increased risk of subsequent AKI (95% CI = 1.07-4.80; P = 0.033). Men with NASDs were at a high risk of AKI (P < 0.05). This nationwide population-based cohort study provides evidence that patients with NASDs are at higher risk of developing AKI than people without NASDs.

Association of sleep duration with kidney function and albuminuria: NHANES 2009-2012

OBJECTIVE

The purpose of this study was to examine the association between self-reported sleep duration and markers of kidney function.

DESIGN

A cross-sectional survey from the 2009-2012 National Health and Nutrition Examination Survey.

SETTING AND PARTICIPANTS

The participants were 8690 adults (e20years) without a previous sleep disorder diagnosis, end-stage kidney failure, or other kidney or liver problems. Subsamples with pre-diabetes and pre-hypertension were examined.

MEASUREMENTS

Participants reported habitual sleep duration, coded as d5, 6, 7, 8, and e9hours per night. Biomarkers of kidney function were determined, including glomerular filtration rate (eGFR) estimated from the Chronic Kidney Disease Epidemiology Collaboration equation, urine albumin-to-creatinine ratio (ACR), microalbuminuria status, and glomerular hyperfiltration status. Weighted and adjusted general linear models assessed associations between sleep duration with eGFR and ACR. Logistic regression analyses evaluated the associations of microalbuminuria and glomerular hyperfiltration status with sleep duration.

RESULTS

Greater eGFR was related to short sleep duration in the total sample and among participants with pre-diabetes. Greater ACR was associated with short and long sleep duration. Short sleep duration (d5hours) was associated with an increased odds for glomerular hyperfiltration (OR, 1.41; 95% CI, 0.97-2.06) and microalbuminuria (OR, 1.31; 95% CI, 0.96-1.79).

CONCLUSIONS

In a US representative sample of adults, self-reported short and long sleep duration were related to higher ACR. Short sleep duration was associated with higher eGFR and microalbuminuria. Research is needed to understand whether these associations indicate increased risk for kidney damage and cardiovascular risk.

Various patterns of disrupted daily rest-activity rhythmicity associated with diabetes

Disruptions to sleep and circadian rhythms have now been recognized as common comorbidities in patients with medical illnesses. We aimed to determine if the diurnal rhythms for rest and activity were disrupted in parallel with the development of diabetic complications. Ninety outpatients in our diabetes clinic who had a body mass index <25 kg m(2) wore an actigraph for 7 consecutive days (42 men; mean age 68.7 ± 8.2 years). Patients with neuropsychiatric diseases, liver cirrhosis, renal failure, chronic obstructive pulmonary disease or blindness, or those who performed shiftwork were excluded. We grouped the actigraph recordings into 1-h periods and counted the number of minutes that showed activity. Stepwise regression analysis showed an association between a diabetic clinical background and measurements of circadian rhythms such as daytime activity, night-time activity, phase, interdaily stability, intradaily variability and relative amplitude. Higher age, body mass index, total cholesterol levels and insulin usage were associated with lower daytime activity and higher intradaily variability, whereas higher haemoglobin A1c levels and the presence of neuropathy were associated with greater daytime activity. The presence of proliferative retinopathy and increased levels of microalbuminuria were associated with higher intradaily variability and lower interdaily stability and amplitude. The presence of cardiovascular disease was associated with advanced phase, whereas painful neuropathy was associated with delayed phase. Our study demonstrated that different diabetic complications were associated independently with a variety of alterations in the circadian rest and activity rhythms. Our findings have provided novel insights that may be helpful in developing interventions for sleep-wake disorders associated with diabetes.

Chronic Kidney Disease and Sleeping Disordered Breathing (SDB)

The outlines of the current manuscript are: 1. Re-establish the link between hypertension and SDB including prevalence, mechanism, and reversal of process (i.e. improvement in hypertension with improvement in SDB), why it is important-cardiovascular mortality with numbers. 2. Re-establish the link between hypertension and CKD including same points as above. Then ask if both CKD and SDB are combined, what happens to hypertension and cardiovascular mortality. 3. Lastly, talk about links between CKD and SDB on how each process feeds on the other and is a growing, common problem.

Risk of obstructive sleep apnea among Saudis with chronic renal failure on hemodialysis

AIM:

The prevalence of obstructive sleep apnea (OSA) in end-stage renal disease (ESRD) patients was reported to be 10-fold that in the general population. OSA can worsen the clinical symptoms and cardiovascular complications of ESRD. We aimed to investigate the prevalence of symptoms and risk of OSA among Saudi patients with ESRD.

SETTINGS AND DESIGN:

This multi-center, cross-sectional study was conducted in Jeddah, Saudi Arabia, between June 2012 and September 2013.

METHODS:

The prevalence of OSA was assessed using the Berlin questionnaire. The presence of daytime sleepiness was evaluated using the Epworth sleepiness scale. Data were also collected on the medical history, clinical, and laboratory findings of participants.

RESULTS:

In all, 355 patients (61% male) were enrolled (mean age: 45.5 ± 15.4 years). The overall prevalence of high-risk of OSA was 44.2% (males, 47.3%; females, 44.8%; P = 0.65). The prevalence of excessive daytime sleepiness (EDS) was 74%. Controlling for age, gender and body mass index, multivariate analysis revealed that hypertension and hepatitis C infection were the only comorbidities significantly associated with OSA (odds ratio [OR]: 3.827 and 0.559; confidence interval [CI]: 2.120-6.906 and 0.324-0.964; P < 0.0001 and 0.036, respectively). OSA was also strongly associated with EDS (OR: 3.054; CI: 1.676-5.565; P < 0.0001).

CONCLUSIONS:

In Saudi Arabia, the risk of OSA is more common in ESRD patients than in the general population. OSA is strongly associated with EDS. Interestingly, a significant negative correlation between OSA and hepatitis C infection was noted, which warrants further investigation.

Impact of sleep disturbances on kidney function decline in the elderly

While sleep disturbances are frequent in renal disease patients, no studies have examined prospectively the associations between sleep disturbances and kidney function decline in community-dwelling elderly subjects.

Glomerular filtration rates (eGFRs) were estimated at baseline and at 11-year follow-up. A glomerular filtration decline over the follow-up period was defined as a percentage decline greater than or equal to the cut-off value of the highest tertile of kidney function decline (22%) in 1105 subjects. Excessive daytime sleepiness (EDS) and insomnia complaints were self-rated at baseline. Restless legs syndrome (RLS) and its age at onset were assessed at study end-point. An ambulatory polysomnography recording was performed during the follow-up in 277 subjects. Apnoea-hypopnoea index (AHI), periodic limb movements during sleep (PLMS) and total sleep time were analysed.

An increased risk of eGFR decline was associated with EDS (OR 1.67, 95% CI 1.18–2.34) and RLS (OR 1.98, 95% CI 1.18–3.30) independently of potential confounders including cardiovascular risk factors. Among insomnia complaints, a borderline association with eGFR decline was found for early morning awakening only. High AHI (≥30 events·h−1) and short total sleep time (<6 h), but not PLMS were linked to eGFR decline in crude associations, but only AHI remained significantly associated after multi-adjustments.

EDS, RLS and AHI constitute independent risk factors for kidney glomerular function decline.

Renoprotective effects of continuous positive airway pressure in chronic kidney disease patients with sleep apnea

PURPOSE

Chronic kidney disease (CKD) is associated with a high incidence of obstructive sleep apnea (OSA). We assessed the effect of continuous positive airway pressure (CPAP) on renal function in patients with CKD and OSA.

METHODS

In this retrospective cohort study, 42 patients with Stage 3-5 CKD and OSA were stratified into two groups: patients who use CPAP more (average >4 h/night on >70 % of nights) and patients who use CPAP less (average ≤4 h/night on ≤70 % of nights). Median follow-up time was 2.3 (1.6-2.9) years for greater and 2.0 (0.6-3.5) years for lesser CPAP users. Chart reviews were carried out to record clinical characteristics, proteinuria measurements by urine dipstick, and eGFR values calculated by CKD-EPI equations. Univariate analyses were performed using Wilcoxon rank-sum and Kruskal-Wallis tests. Multivariate logistic regression models were applied to assess eGFR decline after CPAP prescription.

RESULTS

Twelve (29 %) of the 42 subjects used CPAP more. Groups were similar with respect to age, body mass index, blood pressure, Charlson Comorbidity Index, and baseline eGFR and proteinuria. The median rate of decline of eGFR was significantly slower at -0.07 mL/min/1.73 m(2)/year (range -30 to 13) in those who used more CPAP compared to those who used it less at -3.15 mL/min/1.73 m(2)/year (range -27 to 7) (p = 0.027).Greater use of CPAP was also associated with a significantly reduced level of proteinuria at 0.15 (range 0.0-3.0) versus 0.70 g/L (range 0.0-3.0) (p = 0.046). Less compliant CPAP users were more likely to have progressive decline of eGFR (decline >3 mL/min/1.73 m(2)/year), with unadjusted OR 5.0 (95 % CI 0.93-26.8) and adjusted OR 8.9 (95 % CI 1.1-72.8), adjusting for CCI and baseline eGFR.

CONCLUSIONS

Compliance to CPAP therapy is associated with a slower rate of progression of CKD in patients with CKD and OSA.

Increased risk of progression to dialysis or death in CKD patients with depressive symptoms: A prospective 3-year follow-up cohort study

OBJECTIVE

Comorbid depressive symptoms are common and undertreated in patients with renal diseases. It remains uncertain whether it is an independent risk factor for poor clinical outcome in patients with chronic kidney disease (CKD). This 3-year study investigated the association of depressive symptoms with long-term outcomes, including initiation of dialysis and all-cause mortality, in a population of CKD patients from Taiwan.

METHODS

This prospective cohort study enrolled 262 CKD subjects, none of whom were undergoing dialysis, from a hospital in Taiwan during 2010-2011 and followed them for 3years. At enrollment, all subjects underwent a structured interview with the Taiwan Depression Questionnaire to ascertain the baseline presence of depressive symptoms. Primary end points were initiation of dialysis and all-cause mortality.

RESULTS

A total of 21.4% of enrolled patients (56/262) reported the presence of depressive symptoms at baseline. After 3-year follow-up, the risk of composite events (dialysis or death) was significantly higher in CKD patients with depressive symptoms than in those without depressive symptoms (adjusted hazard ratio [AHR]=2.95, 95% confidence interval [CI]: 1.86-4.72). Depressive symptoms at baseline could independently predict the risk of initiation of dialysis (AHR=2.25, 95% CI: 1.27-4.98) or all-cause mortality (AHR=3.08, 95% CI: 1.69-7.06).

CONCLUSIONS

Depressive symptoms at baseline were independently associated with increased risk of poor clinical outcomes in CKD patients, which suggested that the prompt provision of appropriate psycho-social care may improve the holistic clinical outcomes for CKD patients.

Short sleep duration increases the risk of chronic kidney disease in shift workers

OBJECTIVE

To investigate the association of sleep duration and shift work with development of chronic kidney disease (CKD) in Japanese workers.

METHODS

A total of 3600 participants without CKD were observed for an average of 4.4 years. The Cox proportional-hazards regression model was used to estimate hazard ratios and 95% confidence intervals of the risk of CKD associated with sleep duration and shift work.

RESULTS

Sleep duration and shift work showed no significant association with the risk of CKD. Nevertheless, when the results were stratified by shift work status, short sleep duration was associated with a significantly higher risk of CKD among shift workers (hazard ratio = 3.60; 95% confidence interval: 1.52 to 10.68).

CONCLUSIONS

Short sleep duration was a risk factor for early CKD but only among shift workers.

Obstructive Sleep Apnea and Kidney Disease: A Potential Bidirectional Relationship?

Chronic kidney disease (CKD) is associated with high mortality rates and heavy economic and social burdens. Nearly 10% of the United States population suffer from CKD, with fatal outcomes increased by 16-40 times even before reaching end-stage renal disease. The prevalence of obstructive sleep apnea (OSA) is between 3% and 7% in the general population, and has increased dramatically during the last 2 decades along with increased rates of obesity. However, the prevalence of OSA is much greater in patients with CKD. In addition, aggressive dialysis improves OSA. The current literature suggests a bidirectional association between CKD and OSA through a number of potential pathological mechanisms, which increase the possibility of both diseases being possible risk factors for each other. CKD may lead to OSA through a variety of mechanisms, including alterations in chemoreflex responsiveness, pharyngeal narrowing due to fluid overload, and accumulation of uremic toxins. It is also being increasingly recognized that OSA can also accelerate loss of kidney function. Moreover, animals exposed to intermittent hypoxia suffer histopathological renal damage. Potential mechanisms of OSA-associated renal dysfunction include renal hypoxia, hypertension, endothelial dysfunction, activation of the sympathetic nervous system, and increased oxidative stress.