The Relationship Between Volume Overload in End-Stage Renal Disease and Obstructive Sleep Apnea

Prevalence of obstructive sleep apnea in whole spectrum chronic kidney disease patients: A systematic review and meta-analysis

BACKGROUND

Obstructive sleep apnea (OSA) is a common sleep disorder among chronic kidney disease (CKD) patients, associated with considerable morbidity. Various studies from around the globe have reported different prevalence rates.

OBJECTIVE

This systematic review and meta-analysis aimed to determine the prevalence of OSA and quantify the relationship between OSA and mortality risk in patients with CKD.

METHODS

Four databases were systematically searched, and additional references to relevant articles were manually searched. The prevalence of OSA and the mortality risk based on random-effects models were assessed using percentages and hazard ratio (HR) with a 95 % confidence interval (95 % CI). In addition, the heterogeneity between studies was assessed using I2 statistics.

RESULTS

A total of 44 literature (47 studies with 223,967 participants) met the eligibility criteria for the meta-analysis. The results showed that the prevalence of OSA in CKD patients was reported to be 39.3 % (95 % CI, 32.3-46.7). Among study participants in different age groups, the highest prevalence of OSA was found in CKD respondents aged 60 years or older, at 47.1 % (95 % CI 34.4-60.3). Of the eight literature (10 cohorts) that provided survival data, the pooled estimates indicated a 26.5 % (HR: 1.265; 95 % CI 1.021-1.568) higher mortality risk in subjects with OSA than CKD patients without OSA.

CONCLUSIONS

This systematic review and meta-analysis found that more than 1/3 of CKD patients have comorbid OSA, which increases the risk of early death in CKD patients. These results should help policymakers to provide adequate healthcare for this population.

PROSPERO REGISTRATION ID

CRD42023465497.

High nocturnal periodic breathing reported by PAP adherence data predicts decompensation of heart failure

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) often coexists with heart failure (HF) and is commonly treated with positive airway pressure (PAP) therapy. Periodic breathing (PB) may be present in HF and is an indicator of poor prognosis, but there is no easy way to detect PB in an outpatient setting. However, it can be detected by analyzing PAP usage data. The study aimed to assess if high PB% detected by PAP machine could predict impending HF exacerbation and if better PAP adherence is associated with reduced hospitalization and mortality.

METHODS

We retrospectively reviewed medical records of 115 patients with OSA from the sleep clinic of our VA Medical Center. The cross-sectional data on demographics, labs, PAP adherence, PB% in the previous 30 days, echocardiogram in the previous 6 months, and hospitalizations and mortality in the subsequent 180 days were extracted. Based on left ventricular ejection fraction (LVEF), patients were classified into (1) HF with normal-midrange LVEF (LVEF ≥40%, n = 74) and (2) HF with reduced LVEF (LVEF < 40%, n = 41). Pairwise correlation and linear regressions were done to assess predictors of PB%. Binomial and logistic regressions assessed the relationship of PB% and PAP adherence with hospitalization from HF and all-cause mortality.

RESULTS

In the HF with reduced LVEF group, the mean PB% was 2.6 times higher (P < .001) and PAP adherence was 29% lower (P < .001). PB% positively correlated with brain natriuretic peptide level (r = .447, P < .01) and number of hospitalizations (r = .331, P < .01). Higher PB% negatively correlated with LVEF (r = -.423, P < .01) and estimated glomerular filtration rate (r = -.246, P < .01). Every 10% increase in PAP adherence decreased odds of hospitalization by 0.78 times (P < .001) and odds of death by 0.86 (P = .043).

CONCLUSIONS

High PB% detected by PAP machine data is a predictor of impending HF exacerbation and hospitalization. Improved PAP adherence and optimization of medical therapy may reduce hospitalization and all-cause mortality.

CITATION

Ullah MI, Tamanna S, Bhagat R. High nocturnal periodic breathing reported by PAP adherence data predicts decompensation of heart failure. J Clin Sleep Med. 2023;19(3):431-441.

Alexithymia, Phosphorus Levels, and Sleep Disorders in Patients on Hemodialysis

Alexithymia, or the inability to distinguish between bodily feelings and emotions, has been linked to poor sleep quality in some studies. Rare studies examined the associations between electrolyte phosphorus in patients on hemodialysis and their sleep quality, daytime sleepiness, and alexithymia with inflammatory factors. Hemodialysis is a treatment method for terminal renal patients that involves the diffusion of unwanted metabolic products through the dialyzer membrane. Our study aimed to examine whether there was a difference in phosphorus levels, inflammatory factors, and daytime sleepiness according to the hemodialysis patients’ levels of alexithymia. The study involved 170 HD patients that had been treated with chronic dialysis for more than three months. Prior to the hemodialysis procedure, laboratory findings were sampled. Respondents completed the Pittsburgh Sleep Quality Index, the Toronto Alexithymia Scale 26, and the Epworth Sleepiness Scale, and were questioned about depression. The results showed that alexithymic HD patients exhibited significantly higher leukocyte counts, lower predialysis phosphorus values, and more pronounced daily sleepiness than the alexithymia-free group (Mann−Whitney U test, p = 0.02, p = 0.005, and p < 0.001, respectively). We concluded that alexithymia was an independent predictor of high daytime sleepiness in HD patients (OR = 1.05, 95% CI 1.02 to 1.09).

Relationship between salt intake and sleep disordered breathing in dialysis patients

BACKGROUND

The prevalence of sleep disordered breathing is high in patients with end-stage renal disease. Salt intake is related to the severity of obstructive sleep apnea in patients with resistant hypertension and hyperaldosteronism. We investigated the relationship between salt intake and sleep disordered breathing in patients on maintenance hemodialysis.

PATIENTS AND METHODS

We studied 128 dialysis outpatients (mean age 63 ± 11 years) who were followed at Kokura Daiichi Hospital. We estimated each patient's salt intake using an InBody S10 body composition analyzer and measured the 3% oxygen desaturation index (ODI) during sleep using a Pulsewatch: PMP-200 GplusX.

RESULTS

The average estimated salt intake was 8.0 ± 2.6 g/day, and the median value of that was 7.5 g/day. Blood pressure (BP) before and after dialysis were 140 ± 18/78 ± 11 and 127 ± 13/72 ± 8 mmHg, respectively. The geometric average number of 3% ODI was 7.1, and sleep disordered breathing was detected in 30% of all subjects. The patients with ≥ 7.5 g/day salt intake were younger and more frequently male and had higher body mass index (BMI) and BP before dialysis compared to those with salt intakes < 7.5 g/day. Patients with ≥ 7.5 g/day salt intake had a significantly higher geometric average number of 3% ODI; however, this relationship became weaker after adjusting for BMI. The same relationship was obtained for the prevalence of sleep disordered breathing.

CONCLUSION

The prevalence of sleep disordered breathing in patients on maintenance hemodialysis was high, and the sleep disordered breathing was associated with salt intake and BMI.

Risk of obstructive sleep apnea among senegalese dialysis patients

Obstructive sleep apnea syndrome (OSAS) is a common condition in patients undergoing chronic dialysis and is associated with increased cardiovascular morbidity and mortality. This study aimed to determine the prevalence and risk factors of OSAS in Senegalese dialysis patients. In a cross-sectional study including 128 patients (75 men and 53 women) dialyzed since ≥6 months in four dialysis units. Data were collected during the dialysis session in the units. OSAS was assessed with the Berlin Questionnaire. Factors associated with OSAS risk were identified by multivariate logistic regression. The mean age of patients was 46.8 ± 16.9 ¥16-85 years). OSAS was found in 53 patients (overall prevalence of 41.4%) with predominance among individuals aged ≥50 years (52.6%). Hypertension and diabetes were more frequent in patients with OSAS, while the prevalence of obesity and sedentary was not different. The majority of patients were not aware of their disease before the survey, and none was treated. After multivariate regression analysis, age >50 years [odds ratio (OR) = 1.09, P = 0.02], neck circumference >45 cm (OR= 1.25, P= 0.03), and daytime hypersomnia (OR = 1.18, P= 0.02) were significantly associated with OSAS. This study showed that OSAS is frequent among Senegalese dialysis patients but is usually under-diagnosed. Older age, excessive daytime sleepiness, and neck circumference are the main associated factors.

Intradialytic hypertension is associated with low intradialytic arterial oxygen saturation

Background

The pathophysiology of a paradoxical systolic blood pressure (SBP) rise during hemodialysis (HD) is not yet fully understood. Recent research indicated that 10% of chronic HD patients suffer from prolonged intradialytic hypoxemia. Since hypoxemia induces a sympathetic response we entertained the hypothesis that peridialytic SBP change is associated with arterial oxygen saturation (SaO2).

Methods

We retrospectively analyzed intradialytic SaO2 and peridialytic SBP change in chronic HD patients with arteriovenous vascular access. Patients were followed for 6 months. We defined persistent intradialytic hypertension (piHTN) as average peridialytic SBP increase ≥10 mmHg over 6 months. Linear mixed effects (LME) models were used to explore associations between peridialytic SBP change and intradialytic SaO2 in univariate and adjusted analyses.

Results

We assessed 982 patients (29 872 HD treatments; 59% males; 53% whites). Pre-dialysis SBP was 146.7 ± 26.5 mmHg and decreased on average by 10.1 ± 24.5 mmHg. Fifty-three (5.7%) patients had piHTN. piHTN patients had lower intradialytic SaO2, body weight and interdialytic weight gain. LME models revealed that with every percentage point lower mean SaO2, the peridialytic SBP change increased by 0.46 mmHg (P < 0.001). This finding was corroborated in multivariate analyses.

Conclusion

We observed an inverse relationship between intradialytic SaO2 and the blood pressure response to HD. These findings support the notion that hypoxemia activates mechanisms that partially blunt the intradialytic blood pressure decline, possibly by sympathetic activation and endothelin-1 secretion. To further explore that hypothesis, specifically designed prospective studies are required.

Risk, Severity, and Predictors of Obstructive Sleep Apnea in Hemodialysis and Peritoneal Dialysis Patients

Our study aimed to determine the incidence and severity of obstructive sleep apnea (OSA) in patients with end-stage renal disease (ESRD) and also whether different dialysis modalities confer different risk and treatment response for OSA. We used Taiwan's National Health Insurance Research Database for analysis and identified 29,561 incident dialysis patients as the study cohort between 2000 and 2011. Each dialysis patient was matched with four non-dialysis control cases by age, sex, and index date. Cox regression hazard models were used to identify the risk of OSA. The incidence rate of OSA was higher in the peritoneal dialysis (PD) cohort than the hemodialysis (HD) and control cohort (18.9, 7.03 vs. 5.5 per 10,000 person-years, respectively). The risk of OSA was significantly higher in the PD (crude subhazard ratio (cSHR) 3.50 [95% CI 2.71⁻4.50], p < 0.001) and HD cohort (cSHR 1.31 [95% CI 1.00⁻1.72], p < 0.05) compared with the control cohort. Independent risk factors for OSA in this population were age, sex, having coronary artery disease (CAD), hyperlipidemia, chronic obstructive pulmonary disease (COPD), and hypertension. Major OSA (MOSA) occurred in 68.6% in PD and 50.0% in HD patients with OSA. In the PD subgroup, the incidence of mortality was significantly higher in OSA patients without continuous positive airway pressure (CPAP) treatment compared with OSA patients undergoing CPAP treatment. The results of this study indicate that ESRD patients were at higher risk for OSA, especially PD patients, compared with control. The severity of OSA was higher in PD patients than HD patients. Treatment of MOSA with CPAP was associated with reduced mortality in PD patients.

Association of sleep-disordered breathing with diabetes-associated kidney disease

INTRODUCTION

Diabetes-associated kidney disease is characterized by impairment of renal function and albuminuria. The aim of the present study was to assess whether sleep-disordered breathing is associated with decreased estimated glomerular filtration rate or increased urine-albumin-to-creatinine-ratio independently from known modulators of diabetes-associated kidney disease.

MATERIAL AND METHODS

Estimated glomerular filtration rate and urine-albumin-to-creatinine-ratio were determined in the baseline survey of the DIACORE-SDB substudy, a prospectively planned study of Diabetes mellitus 2 patients. As a measure of the severity of sleep-disordered breathing, the apnea-hypopnea-index was assessed using a 2-channel ambulatory SDB-monitoring device.

RESULTS

A total of 679 patients (mean age 66 years, men 61%, mean body-mass-index 31.2 kg/m²) were analyzed. In multivariable linear regression models adjusting for known modulators of diabetes-associated kidney disease, such as sex, age, body-mass-index, systolic blood pressure, duration of diabetes and HbA1c, apnea-hypopnea-index [beta-estimate -0.2 ml/min/1.73 m², 95% CI (-0.3; -0.1), p = .004], duration of diabetes and age were associated with estimated glomerular filtration rate. Apnea-hypopnea-index [beta-estimate 0.01 mg/g, 95% CI (0.00; 0.02), p = .009], duration of diabetes, HbA1c and systolic blood pressure were associated with ln(urine-albumin-to-creatinine-ratio).

CONCLUSION

In patients with diabetes mellitus type 2, more severe sleep-disordered breathing is significantly associated with lower estimated glomerular filtration rate and increased albuminuria, independent of known modulators of diabetes-associated kidney disease.

Emerging co-morbidities of obstructive sleep apnea: cognition, kidney disease, and cancer

Obstructive sleep apnea (OSA) causes daytime fatigue and sleepiness, and has an established relationship with cardiovascular and metabolic disease. Recent years have seen the emergence of an evidence base linking OSA with an increased risk of degenerative neurological disease and associated cognitive impairment, an accelerated rate of decline in kidney function with an increased risk of clinically significant chronic kidney disease (CKD), and with a significantly higher rate of cancer incidence and death. This review evaluates the evidence base linking OSA with these seemingly unrelated co-morbidities, and explores potential mechanistic links underpinning their development in patients with OSA, including intermittent hypoxia (IH), sleep fragmentation, sympathetic excitation, and immune dysregulation.

Diabetic kidney disease and obstructive sleep apnea: a new frontier?

PURPOSE OF REVIEW

Obstructive sleep apnea (OSA) has been shown to be an independent risk factor for the development and progression of diabetes mellitus. Interestingly, there is also a strong correlation between OSA and the development and progression of chronic kidney disease (CKD). As diabetes mellitus is the most common cause of CKD, in this review we summarize the current literature regarding this interconnecting relationship between OSA, CKD, and diabetes mellitus. The literature increasingly supports a bidirectional relationship between CKD and OSA among diabetes mellitus patients leading to an increased rate of progression of diabetic nephropathy.

RECENT FINDINGS

There is growing evidence that among patients with diabetes mellitus, OSA may be a strong risk factor for the development of diabetic nephropathy. The treatment of OSA in CKD patients may play a role in attenuating the rate of the progression of CKD.

SUMMARY

Clinicians should have a low threshold for evaluating diabetic patients with CKD for OSA. Further studies examining if treatment of OSA would improve the outcomes of CKD patients in general and diabetic CKD patients in particular are needed.

Objective and subjective sleep disorders in automated peritoneal dialysis

Background

Automated peritoneal dialysis (APD) is one of the fastest growing dialysis modalities. It is unknown whether sleep and mood are disturbed while performing repeated overnight exchanges.

Objectives

In this report, we aim to describe and compare the prevalence of sleep-disordered breathing (SDB), periodic limb movements (PLMS), poor sleep quality (SQ), and depression among APD patients compared with stages 3b–5 (estimated glomerular filtration rate ≤44 ml/min/1.73 m2) chronic kidney disease (CKD) and hemodialysis (HD) patients.

Design

This is a cross-sectional, descriptive study.

Setting

Study participants were recruited from outpatient nephrology clinics, local dialysis centers, and the Thomas E. Starzl Transplant Institute in Western Pennsylvania between April 2004 and July 2009.

Patients

There were 186 participants in this study including 22 APD patients, 89 CKD patients, and 75 HD patients.

Measurements

In-home polysomnography was performed and two questionnaires were completed, the Pittsburgh Sleep Quality Index (PSQI) and the Patient Health Questionnaire-9 (PHQ-9).

Methods

SDB and PLMS were quantified by in-home unattended polysomnography; poor SQ was defined by a score >5 on the PSQI, and the presence of moderate to severe depression was defined by a score >5 on the PHQ-9.

Results

The APD patients had a median age of 37.5 years, were predominantly female (72.7 %), and had a median body mass index (BMI) of 23.8 kg/m2. In univariate analyses, APD patients had significantly lower apnea-hypopnea index compared to HD patients by 12.2 points (likelihood ratio test p = 0.008) and revealed the least percent of TST with nocturnal hypoxemia compared to CKD patients by 2.7 points, respectively (likelihood ratio test p = 0.01). The APD group had also significantly greater stages 3 to 4 sleep compared to the CKD patients by 8.6 points (likelihood ratio test p = 0.009). In multivariate analyses and after adjustment for age, gender, race, and BMI, both APD and HD patients had higher average PSQI scores than CKD patients by 2.54 and 2.22 points, respectively (likelihood ratio test p = 0.005). No other comparisons of sleep parameters among groups reached statistical significance.

Limitations

The limitations of this study are the small sample size of the APD population and the demographic and clinical differences among the three study groups.

Conclusions

Despite differences in univariate analyses, after multivariate adjustment, APD patients had similar sleep parameters and sleep architecture and as poor SQ and symptoms of depression as HD patients. Future studies with larger APD cohorts are needed.

Intradialytic Hypoxemia in Chronic Hemodialysis Patients

When kidney failure occurs, patients are at risk for fluid overload states, which can cause pulmonary edema, pleural effusions, and upper airway obstruction. Kidney disease is also associated with impaired respiratory function, as in central sleep apnea or chronic obstructive pulmonary disease. Hence, respiratory and renal diseases are frequently coexisting. Hypoxemia is the terminal pathway of a multitude of respiratory pathologies. The measurement of oxygen saturation (SO2) is a basic and commonly used tool in clinical practice. Both arterial oxygen saturation (SaO2) and central venous oxygen saturation (ScvO2) can be easily obtained in hemodialysis (HD) patients, SaO2 from an arteriovenous access and ScvO2 from a central catheter. Here, we give a brief overview of the anatomy and physiology of the respiratory system, and the different technologies that are currently available to measure oxygen status in dialysis patients. We then focus on literature regarding intradialytic SaO2 and ScvO2. Lastly, we present clinical vignettes of intradialytic drops in SaO2 and ScvO2 in association with different symptoms and clinical scenarios with an emphasis on the pathophysiology of these cases. Given the fact that in the general population hypoxemia is associated with adverse outcomes, including increased mortality, cardiac arrhythmias and cardiovascular events, we posit that intradialytic SO2 may serve as a potential marker to identify HD patients at increased risk for morbidity and mortality.