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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 Author(s) 2022. Published by Oxford University Press on behalf of Sleep Research Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Study Objectives: Chronic kidney disease (CKD) is a global health concern and a major risk factor for cardiovascular morbidity and mortality. Obstructive sleep apnea (OSA) may exacerbate this risk by contributing to the development of CKD. This study investigated the prevalence and patient awareness of the risk of CKD progression in individuals with OSA., Methods: Adults referred to five Canadian academic sleep centers for suspected OSA completed a questionnaire, a home sleep apnea test or in-lab polysomnography and provided blood and urine samples for measurement of estimated glomerular filtration rate (eGFR) and the albumin:creatinine ratio (ACR), respectively. The risk of CKD progression was estimated from a heat map incorporating both eGFR and ACR., Results: 1295 adults (42% female, 54 ± 13 years) were categorized based on the oxygen desaturation index (4% desaturation): <15 (no/mild OSA, n = 552), 15-30 (moderate OSA, n = 322), and >30 (severe OSA, n = 421). After stratification, 13.6% of the no/mild OSA group, 28.9% of the moderate OSA group, and 30.9% of the severe OSA group had a moderate-to-very high risk of CKD progression (p < .001), which was defined as an eGFR <60 mL/min/1.73 m2, an ACR ≥3 mg/mmol, or both. Compared to those with no/mild OSA, the odds ratio for moderate-to-very high risk of CKD progression was 2.63 (95% CI: 1.79-3.85) for moderate OSA and 2.96 (2.04-4.30) for severe OSA after adjustment for CKD risk factors. Among patients at increased risk of CKD progression, 73% were unaware they had abnormal kidney function., Conclusion: Patients with moderate and severe OSA have an increased risk of CKD progression independent of other CKD risk factors; most patients are unaware of this increased risk., (© Sleep Research Society 2021. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Obstructive sleep apnoea is common in chronic kidney disease (CKD) and may accelerate the decline in kidney function. Recruitment for a randomised controlled trial to address whether treatment of sleep apnoea with continuous positive airway pressure (CPAP) slows the progression of kidney failure may be challenging because sleep apnoea is often asymptomatic in this patient population. The present report outlines recruitment challenges and how to address them. Adult patients with CKD were recruited for a 12-month randomised, controlled, non-blinded, parallel clinical trial to evaluate the impact of CPAP therapy on kidney function. Patients completed a home sleep apnoea test and those that met pre-specified sleep apnoea and nocturnal hypoxaemia severity criteria were randomised to receive CPAP or no therapy. Although 1,665 patients were eligible to participate in the study over 3 years, only 57 (3.4%) were ultimately randomised. The sequential reasons (and number of patients) for recruitment failure were: no show at clinic appointment (137), insufficient recruiters to approach every eligible patient (461), on therapy for sleep apnoea (122), unable to provide informed consent (67), refused consent (645), home sleep apnoea test not completed (47) or inclusion criteria not met (116), and declined pre-randomisation education session (12). Many challenges limit effective recruitment, which may be addressed by hiring additional recruiters and increasing the awareness of sleep apnoea among patients with CKD. These findings can be used to improve recruitment strategies and the design of future studies., (© 2021 European Sleep Research Society.)

Background: OSA is common in chronic kidney disease (CKD) and may accelerate a decline in kidney function. It is not clear whether treatment of OSA with CPAP improves kidney function., Research Question: Does treatment with CPAP improve kidney function in patients with CKD and coexisting OSA?, Study Design and Methods: A randomized, controlled, nonblinded, parallel clinical trial was performed of patients with stages 3 and 4 CKD and coexisting OSA comparing the effect of CPAP vs usual care on the estimated glomerular filtration rate (eGFR) and the urine albumin to creatinine ratio (ACR) over 12 months., Results: Fifty-seven patients were enrolled and 30 were randomized to CPAP. They had moderately severe CKD (eGFR, 38.4 ± 1.5 mL/min/1.73 m 2 ) and significant OSA and nocturnal hypoxemia (oxygen desaturation index: 23.9 events/h; interquartile range [IQR], 20.3 events/h; mean peripheral capillary oxygen saturation: 89.5%; IQR, 1.7%); 60% had baseline albuminuria (ACR, > 3 mg/mmol). No significant difference was found between CPAP and usual care in the change in eGFR and ACR over 12 months. Although some improvement in eGFR occurred with CPAP therapy in patients with a lower risk of CKD progression, this did not reach statistical significance., Interpretation: Although CPAP did not provide additional renal benefits over usual care in all CKD patients, some evidence suggested that CPAP slowed the decline in eGFR in CKD patients with a lower risk of CKD progression. These preliminary data support the need for larger clinical trials exploring the effects of CPAP on kidney function., Trial Registry: ClinicalTrials.gov; No.: NCT02420184; URL: www.clinicaltrials.gov., (Copyright © 2020 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Purpose: Chronic kidney disease (CKD) is common in severe obstructive sleep apnoea (OSA), however prevalence in obesity hypoventilation syndrome (OHS) is not known. This study sought to compare prevalence of CKD in OHS and equally obese OSA patients with comparable apnoea hypopnoea indexes (AHI), and secondarily examine the impact of positive airway pressure (PAP) therapy on CKD parameters., Methods: Estimated Glomerular Filtration Rate (eGFR) and spot urine protein creatinine ratio (PCR) were obtained in patients with OHS (Partial pressure of carbon dioxide, PaCO2 > 45 mmHg) and OSA (AHI > 20 events per hour, PaCO2 < 45 mmHg) with a body mass index (BMI) > 40 kg/m 2 . Samples were obtained at baseline and after three months of PAP in both groups., Results: Patients with OHS (n = 15, PaCO2 49 mmHg; daytime oxygen saturation, SpO2 94%; total sleep time with SpO2<90%, T90 308min) and OSA (n = 36, PaCO2 40 mmHg, SpO2 96%, T90 140min) were recruited. Stage 1-3 kidney function was present in 7 (46%) and 8 (22%) patients with OHS and OSA respectively (p = 0.08). Mean PCR was higher in OHS than OSA (23 ± 29 v 10 ± 6 mg/mmol; p = 0.03), while the prevalence of proteinuria was not different (40% v 19%, p = 0.19). Proteinuria was not significantly altered by three months of PAP. Moderate associations were demonstrated between eGFR, PaCO2, awake SpO2 and/or HbA1c (r > 0.5, p < 0.05) in OHS., Conclusion: The prevalence of CKD, primarily early-stage with proteinuria, is at least as frequent in OHS as it is in OSA, if not worse. Markers of CKD were not significantly impacted by PAP therapy., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Introduction: Obstructive sleep apnoea (OSA) is common in patients with chronic kidney disease (CKD) and may contribute to the progression of kidney disease either through direct effects of hypoxia on the kidney or indirectly through hypoxaemia-induced oxidative stress, endothelial dysfunction, inflammation, activation of the renin-angiotensin and sympathetic nervous systems, and hypertension. Treatment of OSA with continuous positive airway pressure (CPAP) improves many of these physiological abnormalities in patients with normal renal function, though to date there are no trials evaluating the effect of OSA treatment on kidney function in patients with CKD. The purpose of this study is to test the feasibility and efficacy of CPAP therapy in CKD patients with OSA., Methods and Analysis: The study is a randomised, controlled, non-blinded, parallel clinical trial in which patients with established CKD are screened for OSA. Patients with OSA are randomised to either conventional medical therapy (control group) or medical therapy and CPAP (CPAP group) and followed for 1 year. The primary outcome is the change in estimated glomerular filtration rate. Secondary outcomes are the change in the urinary albumin/creatinine ratio, the Epworth Sleepiness Scale , Pittsburgh Sleep Quality Index and Kidney Disease Quality of Life questionnaire., Ethics and Dissemination: Ethics approval has been obtained from the Conjoint Health Research Ethics Board (ID: REB15-0055). Results from this study will be disseminated through presentations at scientific conferences and publication in peer-reviewed journals., Trial Registration Number: NCT02420184; Pre-results., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Rationale: Obstructive sleep apnea (OSA) is associated with impaired renal function, but uncertainty exists over whether OSA treatment can influence renal outcomes., Objectives: To determine the effects of continuous positive airway pressure (CPAP) on renal function in subjects with coexisting OSA and cardiovascular disease., Methods: This was a substudy of the international SAVE (Sleep Apnea Cardiovascular Endpoints) trial, in which 2,717 patients with moderate to severe OSA and established coronary or cerebrovascular disease were randomized to receive either CPAP plus usual care or usual care alone. Renal function and adverse renal events were compared between the CPAP (n = 102) and usual care (n = 98) groups. Glomerular filtration rate was estimated at randomization and at the end of follow-up, and the urinary albumin-to-creatinine ratio was measured at study exit., Measurements and Main Results: In 200 substudy participants (mean age, 64 yr; median, 4% oxygen desaturation index; 20 events/h; mean estimated glomerular filtration rate at baseline, 82 ml/min/1.73 m 2 ), the median (interquartile range) changes in estimated glomerular filtration rate (ml/min/1.73 m 2 /yr) were -1.64 (-3.45 to -0.740) in the CPAP group and -2.30 (-4.53 to -0.71) in the usual care group (P = 0.21) after a median of 4.4 years. There were no between-group differences in end-of-study urinary albumin-to-creatinine ratio or in the occurrence of serious renal or urinary adverse events during the trial. The level of CPAP adherence did not influence the findings., Conclusions: CPAP treatment of OSA in patients with cardiovascular disease does not alter renal function or the occurrence of renal adverse events. Clinical trial registered with www.clinicaltrials.gov (NCT00738179).

Study Objectives: To determine the relationship between obstructive sleep apnea (OSA) and chronic kidney disease (CKD). Previous population studies of the association are sparse, conflicting and confined largely to studies of administrative data., Methods: Cross-sectional analysis in unselected participants of the Men Androgens Inflammation Lifestyle Environment and Stress (MAILES) study, aged >40 years. Renal data were available for 812 men without a prior OSA diagnosis who underwent full in-home polysomnography (Embletta X100) in 2010-2011. CKD was defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73m2 or eGFR≥60 and albuminuria (albumin-creatinine ratio ≥3.0 mg/mmol)., Results: CKD (10.5%, n = 85 [Stage 1-3, 9.7%; Stage 4-5, 0.7%]) of predominantly mild severity showed significant associations with OSA (apnea-hypoapnea index [AHI] ≥ 10): odds ratio (OR) = 1.9, 95% confidence interval (CI): 1.02-3.5; severe OSA (AHI ≥ 30/h): OR = 2.6, 95% CI: 1.1-6.2; and respiratory-related arousal index: ≥7.6/h, OR = 2.3, 95%CI: 1.1-4.7; but not measures of hypoxemia after adjustment for age, hypertension, diabetes, smoking, obesity, and NSAID use. There was no association of CKD with daytime sleepiness. In men with CKD, those with OSA were not significantly more likely to report symptoms (sleepiness, snoring, and apneas) or be identified with the STOP OSA screening questionnaire, compared to men without OSA., Conclusions: Predominantly mild CKD is associated with severe OSA and arousals. Further population studies examining the longitudinal relationship between CKD and OSA are warranted. Better methods are needed to identify OSA in CKD which may have few symptoms., (© Sleep Research Society 2016. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.)

The prevalence of chronic kidney disease (CKD) is increasing, which presents challenges for both patients and health-care budgets. Although this phenomenon has been attributed to the growth in diabetes, hypertension, and obesity, sleep apnea and nocturnal hypoxemia may also contribute to the pathogenesis of CKD and its progression to kidney failure. Two pathophysiologic mechanisms responsible for CKD are glomerular hyperfiltration and chronic intrarenal hypoxia, resulting in tubulointerstitial injury, the final common pathway to end-stage kidney disease (ESKD). Multiple descriptive studies have demonstrated an association between CKD and sleep apnea. Although sleep apnea is common in patients with CKD and associated with significant nocturnal hypoxemia, it is often relatively free of sleep-related symptoms, making it difficult to detect without objective nocturnal monitoring. Nevertheless, sleep apnea and nocturnal hypoxemia have been associated with loss of kidney function and kidney injury, suggesting that they contribute to the pathogenesis of continued deterioration in kidney function. There are several pathways through which sleep apnea may achieve this, including a direct effect of intrarenal hypoxia and activation of the systemic and renal renin-angiotensin system. Further research is required to better understand these relationships and determine whether specific interventions in patients with sleep apnea have an impact on clinical outcomes, such as reducing the prevalence of CKD and delaying its progression to ESKD.

Study Objectives: Although restless legs syndrome (RLS) is common and well recognized as an important and potentially treatable cause of sleep disruption in end-stage renal disease (ESRD), few studies have evaluated the prevalence of RLS and its impact on sleep in the non-dialysis-dependent chronic kidney disease (CKD) population. The objectives of the study were to determine the prevalence of RLS across the full spectrum of kidney disease and to assess the impact of RLS on sleep quality and daytime function., Methods: Five hundred patients were recruited from nephrology clinics and were stratified according to estimated glomerular filtration rate (EGFR): eGFR ≥ 60 mL/min/1.73m(2) (n = 127), CKD (eGFR < 60, not on dialysis, n = 242), and ESRD (on hemodialysis, n = 131). All subjects completed a sleep and medical history questionnaire, an RLS questionnaire, the Pittsburgh Sleep Quality Index (PSQI), and the Epworth Sleepiness Scale (ESS)., Results: The prevalence of RLS did not differ among the three groups (18.9% [eGFR ≥ 60], 26% (CKD), and 26% (ESRD) p = 0.27). However, many symptoms of sleep disruption were more common in patients with RLS, and RLS was independently correlated with the PSQI score both in the full cohort (OR = 2.63, CI = 1.60-4.00, p < 0.001) and the CKD group (OR = 2.39, CI = 1.20-4.79, p = 0.014)., Conclusions: RLS is common in non-dialysis-dependent CKD patients and is an important source of sleep disruption.

Background: Obstructive sleep apnea (OSA) is an important and common comorbidity in patients with chronic kidney disease (CKD). However, few studies have addressed how OSA presents in this patient population and whether it is clinically apparent., Objective: The objectives of this study were to determine if the prevalence and severity of sleep related symptoms distinguished CKD patients with OSA from those without apnea, and whether the clinical presentation of OSA in CKD patients differed from the general OSA population., Methods: One hundred nineteen patients were recruited from outpatient nephrology clinics. All patients completed a sleep history questionnaire, the Epworth Sleepiness Scale (daytime sleepiness, ESS > 10), the Pittsburgh Sleep Quality Index (poor sleep quality, PSQI > 5), and underwent overnight cardiopulmonary monitoring for determination of sleep apnea (respiratory disturbance index ≥ 15). CKD patients with OSA (n = 46) were compared to (1) CKD patients without OSA (n = 73) and (2) OSA patients without CKD (n = 230) who were referred to the sleep centre., Results: The prevalence of OSA symptoms and PSQI scores did not differ between CKD patients with OSA and CKD patients without apnea. Although the prevalence of daytime sleepiness was higher in CKD patients with OSA compared to CKD patients without apnea (39% vs. 19%, p = 0.033), both daytime sleepiness and other symptoms of sleep apnea were considerably less frequent than in OSA patients without a history of kidney disease., Conclusions: The presence of OSA in patients with CKD is unlikely to be clinically apparent. Consequently, objective cardiopulmonary monitoring during sleep is required to reliably identify this comorbidity.

Sleep disorders are common and underrecognized in patients at all stages of chronic kidney disease. They include sleep apnea, insomnia, excessive sleepiness, restless legs syndrome and periodic limb movement disorder. They can be related to underlying uremia or comorbidities. Sleep disorders can affect the quality of life, and some are associated with increased morbidity and mortality. Clinical assessment, polysomnography and other standardized assessments are required for diagnosis. Therapeutic approaches include improvement in uremia management, treatment of comorbidities or specific interventions directed at individual sleep disorders. Diagnosis and treatment of sleep disorders in this population may improve quality of life and patient survival., (Copyright © 2011 S. Karger AG, Basel.)