Lower serum sodium level predicts higher risk of infection-related hospitalization in maintenance hemodialysis patients: an observational cohort study

Changes in serum sodium concentration during hemodialysis is a predictor of mortality and cardio-cerebrovascular event

BACKGROUND

Previous study consistently showed that lower serum sodium (SNa) was associated with a greater risk of mortality in hemodialysis (HD) patients. However, few studies have focused on the change in SNa (ΔSNa = post-HD SNa - pre-HD SNa) during an HD session.

METHODS

In a retrospective cohort of maintenance HD adults, all-cause mortality and cardio-cerebrovascular event (CCVE) were followed up for a medium of 82 months. Baseline pre-HD SNa and ΔSNa were collected; time-averaged pre-HD SNa and ΔSNa were computed as the mean values within 1-year, 2-year and 3-year intervals after enrollment. Cox proportional hazards models were used to evaluate the relationships of pre-HD and ΔSNa with outcomes.

RESULTS

Time-averaged pre-HD SNa were associated with all-cause mortality (2-year pre-HD SNa: HR [95% CI] 0.86 [0.74-0.99], p = 0.042) and CCVE (3-year pre-HD SNa: HR [95% CI] 0.83 [0.72-0.96], p = 0.012) with full adjustment. Time-averaged ΔSNa also demonstrated an association with all-cause mortality (3-year ΔSNa: HR [95% CI] 1.26 [1.03-1.55], p = 0.026) as well as with CCVE (3-year ΔSNa: HR [95% CI] 1.51 [1.21-1.88], p = <0.001) when fully adjusted. Baseline pre-HD SNa and ΔSNa didn't exhibit association with both outcomes.

CONCLUSIONS

Lower time-averaged pre-HD SNa and higher time-averaged ΔSNa were associated with a greater risk of all-cause mortality and CCVE in HD patients.

Patterns and outcomes of health-care associated infections in the medical wards at Bugando medical centre: a longitudinal cohort study

BACKGROUND

The burden of healthcare associated infections (HCAIs) in low- and middle-income countries (LMICs) remains underestimated due to diagnostic complexity and lack of quality surveillance systems. We designed this study to determine clinical diagnosis, laboratory-confirmed, associated factors and risks of HCAIs.

METHODS

This hospital-based longitudinal cohort study was conducted between March and June 2022 among adults (≥ 18 years) admitted in medical wards at BMC in Mwanza, Tanzania. Patients who were negative for HCAIs by clinical evaluations and laboratory investigations during admission were enrolled and followed-up until discharge or death. Clinical samples were collected from patients with clinical diagnosis of HCAIs for conventional culture and antimicrobial sensitivity testing.

RESULTS

A total of 350 adult patients with a median [IQR] age of 54 [38-68] years were enrolled in the study. Males accounted for 54.6% (n = 191). The prevalence of clinically diagnosed HCAIs was 8.6% (30/350) of which 26.7% (8/30) had laboratory-confirmed HCAIs by a positive culture. Central-line-associated bloodstream infection (43.3%; 13/30) and catheter-associated urinary tract infection (36.7%; 11/30) were the most common HCAIs. Older age was the only factor associated with development of HCAIs [mean (± SD); [95%CI]: 58.9(± 12.5); [54.2-63.5] vs. 51.5(± 19.1); [49.4-53.6] years; p = 0.0391) and HCAIs increased the length of hospital stay [mean (± SD); [95%CI]: 13.8 (± 3.4); [12.5-15.1] vs. 4.5 (± 1.7); [4.3-4.7] days; p < 0.0001].

CONCLUSION

We observed a low prevalence of HCAIs among adult patients admitted to medical wards in our setting. Central-line-associated bloodstream infections and catheter-associated urinary tract infections are common HCAIs. Significantly, older patients are at higher risk of acquiring HCAIs as well as patients with HCAIs had long duration of hospital stays.

Prevalence of hyponatremia and associated factors in patients with chronic kidney disease: the Fukuoka Kidney Disease Registry (FKR) study

BACKGROUND

Hyponatremia is a common and important electrolyte disorder. However, the prevalence and factors associated with hyponatremia in patients with chronic kidney disease (CKD) are unknown.

METHODS

We studied the factors associated with hyponatremia (< 135 mEq/L) in CKD patients registered in the Fukuoka Kidney Disease Registry (FKR) study using a logistic regression model variable selected using the variable reduction method.

RESULTS

We analyzed the baseline characteristics of 4367 participants with CKD (age, 64 ± 16 years; male, 56.1%). Hyponatremia was detected in 2.0% of the patients at baseline, and multivariate logistic analysis showed that the independent factors for hyponatremia were body mass index (odds ratio [OR] 0.91; 95% confidence interval [CI] 0.85-0.97), prescription of benzodiazepine (OR 2.31; 95% CI 1.39-3.86), blood hemoglobin level (OR 0.76; 95% CI 0.65-0.88), and serum C-reactive protein level (OR 1.27; 95% CI 1.04-1.54).

CONCLUSION

The cross-sectional analysis using baseline data from the FKR study revealed independent factors associated with hyponatremia in patients with decreased kidney function. Longitudinal analyses of the FKR cohort are needed to evaluate the effects of these factors on the prognosis of hyponatremia in patients with CKD.

Prevalence, Microbial Etiology and Risk Factors Associated With Healthcare Associated Infections Among End Stage Renal Disease Patients on Renal Replacement Therapy

End stage renal disease (ESRD) patients on renal replacement therapy (RRT) have an increased risk of morbidity and mortality due to healthcare associated infections (HCAIs). The aim of this study is to determine the prevalence, microbial etiology, and risk factors associated with HCAIs among ESRD patients on RRT. A multicenter, retrospective study was conducted from June to December 2019. ESRD patients with minimum of 6 months on RRT were included, while pregnant patients and patients <18 years were excluded. To reduce the risk of selection bias, all patients were randomly selected using a simple random sampling technique. The prevalence showing the proportion of patients that acquired HCAI since the initiation of dialysis until 2019 was calculated using the European patients' academy (EUPATI) formula. Risk factors were assessed using univariate and multivariate regression analysis. The prevalence of HCAI among ESRD patients was 174/400 (43.5%). Catheter related bloodstream infection (CRBSI) was the most common infection [64(36.8%)], followed by peritonitis [45(25.8%)] and pneumonia [37(21.2%)]. Out of 382 total pathogens identified, 204 (53.4%) were Gram positive and 162 (42.4%) were Gram negative. Both methicillin sensitive staphylococcus aureus (MSSA) and methicillin resistant staphylococcus aureus (MRSA) showed statistically significant associations (p<0.05) with CRBSI. Use of multiple accesses, increased blood sugar levels, low serum sodium levels and higher CRP concentration increased the occurrence of HCAIs. The burden of HCAIs among the patients undergoing RRT is high. Preventive strategies and optimum empirical therapy of antibiotics should be used to reduce the risk of these infections among ESRD patients.

Results of Salt Intake Restriction Monitored with the New Sodium Control Biosensor

INTRODUCTION

Adherence to a low-sodium (Na) diet is crucial in patients under hemodialysis, as it improves cardiovascular outcomes and reduces thirst and interdialytic weight gain. Recommended salt intake is lower than 5 g/day. The new 6008 CAREsystem monitors incorporate a Na module that offers the advantage of estimating patients' salt intake. The objective of this study was to evaluate the effect of dietary Na restriction for 1 week, monitored with the Na biosensor.

METHODS

A prospective study was conducted in 48 patients who maintained their usual dialysis parameters and were dialyzed with a 6008 CAREsystem monitor with activation of the Na module. Total Na balance, pre-/post-dialysis weight, serum Na (sNa), changes in pre- to post-dialysis sNa (ΔsNa), diffusive balance, and systolic and diastolic blood pressure were compared twice, once after 1 week of patients' usual Na diet and again after another week with more restricted Na intake.

RESULTS

Restricted Na intake increased the percentage of patients on a low-Na diet (<85 Na mmol/day) from 8% to 44%. Average daily Na intake decreased from 149 ± 54 to 95 ± 49 mmol, and interdialytic weight gain was reduced by 460 ± 484 g per session. More restricted Na intake also decreased pre-dialysis sNa and increased both intradialytic diffusive balance and ΔsNa. In hypertensive patients, reducing daily Na by more than 3 g Na/day lowered their systolic blood pressure.

CONCLUSIONS

The new Na module allowed objective monitoring of Na intake, which in turn could permit more precise personalized dietary recommendations in patients under hemodialysis.

Hyponatremia in peritoneal dialysis patients

Hyponatremia is the most common disorder of body fluid and electrolyte balance encountered in clinical practice, and also in peritoneal dialysis (PD) population. Depending on the severity and the speed of drop in sodium concentration, the symptoms can vary from asymptomatic hyponatremia to mild and non-specific symptoms or severe and life-threatening situations. Hyponatremia is associated with high morbidity and mortality. Its pathophysiology is complex, specifically in patients undergoing PD. The etiological workup can be cumbersome but is of paramount importance for early and appropriate treatment. In this article, we review the clinical manifestations as well as the pathophysiology and the specific etiologies of hyponatremia in peritoneal dialysis patients, and we propose a diagnostic algorithm.   

Dysnatremia and risk of bloodstream infection in dialysis patients

Background

Emerging data suggest that sodium disarrays including hyponatremia are potential risk factors for infection ensuing from impairments in host immunity, which may be exacerbated by coexisting conditions (i.e. mucosal membrane and cellular edema leading to breakdown of microbial barrier function). While dysnatremia and infection-related mortality are common in dialysis patients, little is known about the association between serum sodium levels and the risk of bloodstream infection in this population.

Methods

Among 823 dialysis patients from the national Biospecimen Registry Grant Program who underwent serum sodium testing over the period January 2008–December 2014, we examined the relationship between baseline serum sodium levels and subsequent rate of bloodstream infection. Bloodstream infection events were directly ascertained using laboratory blood culture data. Associations between serum sodium level and the incidence of bloodstream infection were estimated using expanded case mix–adjusted Poisson regression models.

Results

In the overall cohort, ∼10% of all patients experienced one or more bloodstream infection events during the follow-up period. Patients with both lower sodium levels <134 mEq/l and higher sodium levels ≥140 mEq/l had higher incident rate ratios (IRRs) of bloodstream infection in expanded case mix analyses (reference 136–<138 mEq/l), with adjusted IRRs of 2.30 [95% confidence interval (CI) 1.19–4.44], 0.77 (95% CI 0.32–1.84), 1.39 (95% CI 0.78–2.47), 1.88 (95% CI 1.08–3.28) and 1.96 (95% CI 1.08–3.55) for sodium levels <134, 134–<136, 138–<140, 140–<142 and ≥142 Eq/l, respectively.

Conclusions

Both lower and higher baseline serum sodium levels were associated with a higher rate of subsequent bloodstream infections in dialysis patients. Further studies are needed to determine whether correction of dysnatremia ameliorates infection risk in this population.

The impact of chronic pre-dialysis hyponatremia on clinical outcomes in maintenance hemodialysis patients

OBJECTIVE

Chronic pre-dialysis hyponatremia is not rare in maintenance hemodialysis (MHD) patients. However, the association between chronic pre-dialysis hyponatremia and mortality is uncertain due to multiple potential confounders such as hyperglycemia, fluid overload, and malnutrition. This study aimed to more comprehensively evaluate the association between chronic pre-dialysis hyponatremia and clinical outcomes in MHD patients.

METHODS

We analyzed the data of 194 MHD patients with regular real-time measurements of pre-dialysis serum sodium from July 2015 to March 2021. Hyponatremia was defined as SNa ≤ 135 mmol/L and normonatremia as SNa > 135 mmol/L and < 145 mmol/L. We evaluated the association of baseline pre-dialysis serum sodium (SNa) and time-averaged SNa (TASNa) levels with all-cause mortality or new major adverse cardiovascular events (MACE) in MHD patients. Furthermore, the SNa levels were glucose, serum albumin, and fluid overload adjusted. The associations between SNa levels and all-cause mortality or new MACE were analyzed using time-varying Cox regression models.

RESULTS

Among the total of 194 patients, 24 patients died and 45 new MACE occurred during a mean 35.2-month follow-up period. The baseline pre-dialysis SNa level was 137.1 ± 2.8 mmol/L (127-144 mmol/L). Kaplan-Meier survival analysis showed that there were no significant differences in all-cause mortality or new MACE between hyponatremia and normonatremia groups according to baseline pre-dialysis SNa or glucose-corrected SNa (gcSNa). The mean values of both TASNa and time-averaged glucose-corrected SNa (TAgcSNa) were 136.9 ± 2.4 mmol/L and 138.3 ± 2.0 mmol/L, respectively. Kaplan-Meier survival analysis showed that patients with pre-dialysis hyponatremia had higher all-cause mortality or new MACE compared with normonatremia patients whether grouped on TASNa or TAgcSNa. Cox models showed an increased risk of all-cause mortality and new MACE in MHD patients with pre-dialysis hyponatremia based on TASNa or TAgcSNa. Even after full adjustment including time-dependent age and dialysis vintage, gender, diabetes, time-averaged weight gain (TAWG), and serum albumin, patients with pre-dialysis hyponatremia based on TASNa (HR 2.89; 95% CI 1.18-7.04; model 3) or TAgcSNa (HR 5.03; 95% CI 1.87-13.57; model 3) had approximately twofold or fourfold greater risk of all-cause mortality, respectively, compared with those with normonatremia. The risk of new MACE was also significantly elevated in patients with pre-dialysis hyponatremia based on TASNa (HR 3.86; 95% CI 2.13-7.01; model 1) or TAgcSNa (HR 2.43; 95% CI 1.14-5.15; model 1). After adjustment for time-dependent age and dialysis vintage, gender, diabetes, TAWG, and serum albumin, patients with pre-dialysis hyponatremia based on TASNa (HR 2.33; 95% CI 1.16-4.68; model 3) had a higher risk of new MACE compared with those with normonatremia.

CONCLUSIONS

Pre-dialysis time-averaged hyponatremia is independently associated with increased risks of all-cause mortality or new MACE in MHD patients. The baseline SNa level is not a predictor of clinical outcomes due to its variation over time. Hyperglycemia, fluid overload, and malnutrition do not have a significant impact on the risk association between chronic hyponatremia and all-cause mortality or new MACE in MHD patients.

Epidemiology of haemodialysis outcomes

Haemodialysis (HD) is the commonest form of kidney replacement therapy in the world, accounting for approximately 69% of all kidney replacement therapy and 89% of all dialysis. Over the last six decades since the inception of HD, dialysis technology and patient access to the therapy have advanced considerably, particularly in high-income countries. However, HD availability, accessibility, cost and outcomes vary widely across the world and, overall, the rates of impaired quality of life, morbidity and mortality are high. Cardiovascular disease affects more than two-thirds of people receiving HD, is the major cause of morbidity and accounts for almost 50% of mortality. In addition, patients on HD have high symptom loads and are often under considerable financial strain. Despite the many advances in HD technology and delivery systems that have been achieved since the treatment was first developed, poor outcomes among patients receiving HD remain a major public health concern. Understanding the epidemiology of HD outcomes, why they might vary across different populations and how they might be improved is therefore crucial, although this goal is hampered by the considerable heterogeneity in the monitoring and reporting of these outcomes across settings.

This Review examines the epidemiology of haemodialysis outcomes — clinical, patient-reported and surrogate outcomes — across world regions and populations, including vulnerable individuals. The authors also discuss the current status of monitoring and reporting of haemodialysis outcomes and potential strategies for improvement.

Nearly 4 million people in the world are living on kidney replacement therapy (KRT), and haemodialysis (HD) remains the commonest form of KRT, accounting for approximately 69% of all KRT and 89% of all dialysis.

Dialysis technology and patient access to KRT have advanced substantially since the 1960s, particularly in high-income countries. However, HD availability, accessibility, cost and outcomes continue to vary widely across countries, particularly among disadvantaged populations (including Indigenous peoples, women and people at the extremes of age).

Cardiovascular disease affects over two-thirds of people receiving HD, is the major cause of morbidity and accounts for almost 50% of mortality; mortality among patients on HD is significantly higher than that of their counterparts in the general population, and treated kidney failure has a higher mortality than many types of cancer. Patients on HD also experience high burdens of symptoms, poor quality of life and financial difficulties.

Careful monitoring of the outcomes of patients on HD is essential to develop effective strategies for risk reduction. Outcome measures are highly variable across regions, countries, centres and segments of the population. Establishing kidney registries that collect a variety of clinical and patient-reported outcomes using harmonized definitions is therefore crucial.

Evaluation of HD outcomes should include the impact on family and friends, and personal finances, and should examine inequities in disadvantaged populations, who comprise a large proportion of the HD population.

Association between salt intake and long-term mortality in hemodialysis patients: A retrospective cohort study

Background

The association between salt intake and clinical outcomes in hemodialysis patients has been controversial. This study aimed to clarify the association between salt intake and mortality in hemodialysis patients.

Method

The present study included patients who underwent hemodialysis from June 1st 2016 to May 31st 2020. Corrected salt intake by ideal body weight was the main predictor of outcomes. Ideal body weight was calculated assuming that the ideal body mass index is 22 kg/m² for the Japanese population. The multivariate Cox proportional hazards model was used to determine the association between corrected salt intake and mortality, adjusting for potential confounders. The outcomes considered were all-cause mortality and cumulative incidence of cardiovascular events at year 4.

Result

A total of 492 adult patients were enrolled in the study. The mean daily salt intake and corrected salt intake at baseline were 9.5 g/day and 0.17 g/kg/day, respectively. The low corrected salt intake group (< 0.13 g/kg/day) demonstrated the highest 4-year all-cause mortality. No association was observed between corrected salt intake and the cumulative incidence of cardiovascular events. In multivariate Cox proportional hazards analysis, only the group with corrected salt intake of 0.16–0.20 g/kg/day was associated with a decreased hazard risk for all-cause death compared with the low corrected salt intake group.

Conclusion

The present study found that a low salt intake was associated with high all-cause mortality in hemodialysis patients. Reduced long-term survival may be attributed to malnutrition resulting from excessive salt restriction.

Dysnatremias in Chronic Kidney Disease: Pathophysiology, Manifestations, and Treatment

The decreased ability of the kidney to regulate water and monovalent cation excretion predisposes patients with chronic kidney disease (CKD) to dysnatremias. In this report, we describe the clinical associations and methods of management of dysnatremias in this patient population by reviewing publications on hyponatremia and hypernatremia in patients with CKD not on dialysis, and those on maintenance hemodialysis or peritoneal dialysis. The prevalence of both hyponatremia and hypernatremia has been reported to be higher in patients with CKD than in the general population. Certain features of the studies analyzed, such as variation in the cut-off values of serum sodium concentration ([Na]) that define hyponatremia or hypernatremia, create comparison difficulties. Dysnatremias in patients with CKD are associated with adverse clinical conditions and mortality. Currently, investigation and treatment of dysnatremias in patients with CKD should follow clinical judgment and the guidelines for the general population. Whether azotemia allows different rates of correction of [Na] in patients with hyponatremic CKD and the methodology and outcomes of treatment of dysnatremias by renal replacement methods require further investigation. In conclusion, dysnatremias occur frequently and are associated with various comorbidities and mortality in patients with CKD. Knowledge gaps in their treatment and prevention call for further studies.

Association of Pre-ESKD Hyponatremia with Post-ESKD Outcomes among Incident ESKD Patients

BACKGROUND

Hyponatremia is one of the most common electrolyte disturbances in advanced chronic kidney disease (CKD) and end-stage kidney disease (ESKD) patients and has been shown to be associated with higher mortality risk. However, the relationship between hyponatremia during late-stage CKD and the risk of poor outcomes after ESKD transition is unknown.

METHODS

We conducted a retrospective cohort study including 32,257 US veterans transitioning to ESKD from October 1, 2007 to March 30, 2015. We evaluated adjusted associations between the 3-month averaged pre-transition to ESKD serum sodium and all-cause mortality. Secondary outcomes included cardiovascular (CV) mortality, infection-related mortalities, and hospitalization rate.

RESULTS

Cohort mean±SD serum sodium was 139 ± 3 mEq/L, mean age was 67 ± 11 years, 98% were male, and 32% were African American. Over a median follow-up of 702 days (296, 1301) there were 17,162 deaths. Compared to the reference of 135-<144 mEq/L, the lowest serum sodium group (<130 mEq/L) had a 54% higher all-cause mortality risk (hazard ratio [HR]: 1.54, 95% confidence interval [CI]: 1.34, 1.76) in the fully adjusted model. Associations were similar for CV and infection-related mortality, and hospitalization outcomes.

CONCLUSIONS

Hyponatremia prior to ESKD transition is associated with higher risk of all-cause, CV, and infection-related mortalities and hospitalization rates after ESKD transition. Future studies evaluating management of pre-ESKD hyponatremia may be indicated to improve patient outcomes for those transitioning to ESKD.

Impact of Healthcare Associated Infections on Survival and Treatment Outcomes Among End Stage Renal Disease Patients on Renal Replacement Therapy

Background: Due to frequent hospitalizations, complex dialysis procedures and immune compromising effects of end stage renal disease (ESRD), patients on dialysis are more prone to healthcare associated infections (HCAIs). Objective: To study the impact of HCAIs on survival and treatment outcomes among ESRD patients on renal replacement therapy (RRT). Methodology: A multicenter, retrospective study was conducted from June to December 2019 at two public hospitals of Malaysia. ESRD patients with minimum of 6 months on RRT were included, while pregnant patients and patients <18 years were excluded. Multinomial logistic regression was performed to identify risk factors associated with unsuccessful treatment outcomes. Kaplan Meier analysis was performed to study the survival. Results: A total of 670 records were examined, of which 400 patients were included as per the inclusion criteria. The mean survival time of patients without HCAIs [22.7 (95%CI:22.1-23.2)] was higher than the patients with HCAIs [19.9 (95%CI:18.8-20.9)]. Poor survival was seen in patients with >2 comorbidities, >60 years of age, low hemoglobin concentration and high C-reactive protein levels. The most frequent treatment outcome was cured [113 (64.9%)], followed by death [37 (21.3%)] and treatment failure [17 (9.8%)]. Advancing age, and low hemoglobin concentration were independent risk factors associated with death, while recurrent HCAIs, use of central venous catheters, and low serum sodium levels were risk factors for treatment failure. Conclusion: The high burden of HCAIs is a profound challenge faced by patients on RRT, which not only effects the treatment outcomes but also contributes substantially to the poor survival among these patients.

A Systematic Review and Meta-Analysis: Hyponatremia Predicted All-Cause and Cardiovascular Mortality in Dialysis Population

BACKGROUND

Hyponatremia is one of the most common disorders of electrolytes. Some research studies reported that hyponatremia was closely associated with mortality in patients with dialysis. However, this viewpoint remains controversial.

OBJECTIVE

We aimed to do a systematic review and meta-analysis to assess the influence of hyponatremia on mortality in patients with dialysis.

METHODS

We identified the eligible studies that investigated the association between hyponatremia and mortality risk in patients under dialysis by searching systematically a series of databases including PubMed, Embase, Cochrane, Web of science, and Ovid from January 2011 to June 2020. Adjusted hazard ratios (HRs) with 95% confidence intervals (95% CIs) were pooled.

RESULTS

From 1,116 records identified, 12 studies including prospective and retrospective cohort studies met our inclusion criteria. We found hyponatremia both at baseline (HR: 1.50 and 95% CI: 1.41-1.59) and in time-varying (HR: 1.63 and 95% CI: 1.44-1.84) were significantly correlated to all-cause mortality after multivariable adjusted. By the subgroup analysis, the same results were presented in hemodialysis (HR: 1.48 and 95% CI: 1.38-1.59) or peritoneal dialysis patients (HR: 1.52 and 95% CI: 1.37-1.70). We also observed that lower serum sodium was independently associated with cardiovascular death.

CONCLUSIONS

Hyponatremia was independently associated with all-cause and cardiovascular mortality, and it might predict adverse outcomes of patients under dialysis.

Prevalence, risk factors and impact on outcomes of 30-day unexpected rehospitalization in incident peritoneal dialysis patients

Background

Rehospitalization is a major problem for end stage renal disease (ESRD) populations. However, researches on 30-day unexpected rehospitalzation of incident peritoneal dialysis (PD) patients were limited. This study aimed to investigate the prevalence, risk factors and impact on outcomes of 30-day unexpected rehospitalization in incident PD patients.

Methods

This was a retrospective cohort study. Patients who accepted PD catheter implantation in our centre from Jan 1, 2006 to Dec 31, 2013 and regular follow-up were included. The demographic characteristics, laboratory parameters, and rehospitalization data were collected and analyzed. The primary outcome was all-cause mortality, and the secondary outcomes included cardiovascular disease (CVD) mortality and technical failure.

Results

Totally 1632 patients (46.9 ± 15.3 years old, 60.1% male, 25.6% with diabetes) were included. Among them, 149 (9.1%) had a 30-day unexpected rehospitalization after discharge. PD-related peritonitis (n = 48, 32.2%), catheter malfunction (n = 30, 20.1%) and severe fluid overload (n = 19, 12.8%) were the top three causes for the rehospitalization. Multivariate logistic regression analysis showed that length of index hospital stays [Odds ratio (OR) =1.02, 95% confidence interval (CI) 1.00–1.03, P = 0.036) and hyponatremia (OR = 1.85, 95% CI 1.06–3.24, P = 0.031) were independently associated with the rehospitalization. Multivariate Cox regression analysis indicated that 30-day rehospitalization was an independent risk factor for all-cause mortality [Hazard ratio (HR) =1.52, 95% CI 1.07–2.16, P = 0.019) and CVD mortality (HR = 1.73, 95% CI 1.03–2.90, P = 0.038).

Conclusions

The prevalence of 30-day unexpected rehospitalization for incident PD patients in our centre was 9.1%. The top three causes for the rehospitalization were PD-related peritonitis, catheter malfunction and severe fluid overload. Thirty-day unexpected rehospitalization increased the risk of all-cause mortality and CVD mortality for PD patients.

Pre-dialysis Hyponatremia and Change in Serum Sodium Concentration During a Dialysis Session Are Significant Predictors of Mortality in Patients Undergoing Hemodialysis

Background

Previous studies have shown that hyponatremia is associated with greater mortality in hemodialysis (HD) patients. However, there have been few reports regarding the importance of the change in serum sodium (SNa) concentration (ΔSNa) during dialysis sessions. To investigate the relationships of pre-dialysis hyponatremia and ΔSNa during a dialysis session with mortality, we analyzed data from a national registry of Japanese patients with end-stage kidney disease.

Methods

We identified 178,114 patients in the database who were undergoing HD 3 times weekly. The study outcome was 2-year all-cause mortality, and the baseline SNa concentrations were categorized into quintiles. We evaluated the relationships of SNa concentration and ΔSNa with mortality using Cox proportional hazards models.

Results

During a 2-year follow-up period, 25,928 patients died. Each 1-mEq/l reduction in pre-HD SNa concentration was associated with a cumulatively greater risk of all-cause mortality (hazard ratio [HR], 1.05; 95% confidence interval [CI], 1.05–1.06). In contrast, a larger ΔSNa was associated with higher all-cause mortality (HR for a 1-mEq/l increase in ΔSNa, 1.02; 95% CI 1.01–1.02). The combination of low pre-HD SNa concentration and large ΔSNa was also associated with higher mortality (HR 1.09; 95% CI 1.05–1.13). Participants with the lowest SNa concentration (≤136 mEq/L) and the highest ΔSNa (>4 mEq/L) showed higher mortality than those with an intermediate pre-HD SNa concentration (137–140 mEq/L) and the lowest ΔSNa (≤2 mEq/L).

Conclusions

Lower pre-HD SNa concentration and higher ΔSNa are associated with a greater risk of mortality in patients undergoing HD.

Chronicity of Uncorrected Hyponatremia and Clinical Outcomes in Older Patients Undergoing Hip Fracture Repair

Background: Chronic hyponatremia is a risk factor for hip fracture but remains uncorrected in most patients. This study evaluated if preoperative chronicity of uncorrected hyponatremia influences outcomes after hip fracture repair.

Materials and Methods: Evaluated were older patients hospitalized for hip fracture repair between 2007 and 2012 with plasma sodium measured at admission and ≥1 preadmission outpatient measurement. Patients were classified as being normonatremic (NN; plasma sodium 135–145 mmol/L), chronic prolonged hyponatremia (CPH; ≥2 consecutive plasma sodium values <135 mmol/L over >90 days), or recent hyponatremia (one plasma sodium <135 mmol/L within 30 days before admission with previously normal plasma sodium). Length of hospital stay, in-hospital death, post-operative complications, 30-day readmission, and long-term mortality were the evaluated outcomes. Multivariable Cox regression was used to evaluate the association of hyponatremia status with outcomes.

Results: Among 1,571 eligible patients, 76.7% were NN, 14% had CPH, and 9.1% had RH. Compared with NN patients, CHN patients were older and had more prior heart failure, alcoholism, and anticonvulsant drug use. In multivariable analyses, neither CPH or RH was associated with hospital length of stay, in-hospital or 30-day death, or 30-day readmission, while RH was associated with post-operative sepsis [adjusted odds ratio (aOR) 1.84, 95% CI: 1.01–3.35). Only CPH was independently associated with long-term all-cause death (OR 1.53, 95% CI: 1.12–2.09).

Conclusions: Hyponatremia affects nearly 25% of patients undergoing hip fracture repair. Preoperative chronic untreated hyponatremia is associated with increased post-operative mortality following surgical repair of a hip fracture in older patients. Future studies should evaluate if correction of hyponatremia could decrease long-term mortality after hip fracture repair.

Hyponatremia in the Dialysis Population

Sodium derangements are among the most frequently encountered electrolyte disorders in patients with end-stage renal disease. As dialysis patients are predisposed to hyponatremia via multiple pathways, assessment of extracellular volume status is an essential first step in disentangling potential etiologic factors. In addition, multiple large population-based studies indicate that proxies of malnutrition (e.g., low body mass index, serum albumin, and serum creatinine levels) and loss of residual kidney function are important determinants of hyponatremia in dialysis patients. Among hemodialysis and peritoneal dialysis patients, evidence suggests that incrementally lower sodium levels are associated with increasingly higher death risk, highlighting the long-term risk of hyponatremia. Whereas in conventional survival models incrementally lower serum sodium concentrations are associated with worse mortality in hemodialysis patients, studies that have examined repeated measures of predialysis sodium have demonstrated mixed associations of time-varying sodium with higher mortality risk (i.e., U-shaped vs. inverse linear relationships). Although the causality of the hyponatremia-mortality association in dialysis patients remains uncertain, there are several plausible pathways by which lower sodium levels may lead to higher death risk, including central nervous system toxicity, falls and fractures, infection-related complications, and impaired cardiac function. Areas of uncertainty ripe for future studies include the following: (i) mechanistic pathways by which lower serum sodium levels are linked with higher mortality in dialysis patients, (ii) whether correction of sodium derangements improves outcomes, (iii) the optimal sodium target, and (iv) the impact of age and other sociodemographic factors on hyponatremia-outcome associations.

Syndrome of Inappropriate Antidiuresis

The syndrome of inappropriate antidiuresis (SIAD) is a common cause of hyponatremia in hospitalized children. SIAD refers to euvolemic hyponatremia due to nonphysiologic stimuli for arginine vasopressin production in the absence of renal or endocrine dysfunction. SIAD can be broadly classified as a result of tumors, pulmonary or central nervous system disorders, medications, or other causes such as infection, inflammation, and the postoperative state. The presence of hypouricemia with an elevated fractional excretion of urate can aid in the diagnosis. Treatment options include fluid restriction, intravenous saline solutions, oral sodium supplements, loop diuretics, oral urea, and vasopressin receptor antagonists (vaptans).

Low dialysate sodium levels for chronic haemodialysis

BACKGROUND

Cardiovascular (CV) disease is the leading cause of death in dialysis patients, and strongly associated with fluid overload and hypertension. It is plausible that low dialysate [Na+] may decrease total body sodium content, thereby reducing fluid overload and hypertension, and ultimately reducing CV morbidity and mortality.

OBJECTIVES

This review evaluated harms and benefits of using a low (< 138 mM) dialysate [Na+] for maintenance haemodialysis (HD) patients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 7 August 2018 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs), both parallel and cross-over, of low (< 138 mM) versus neutral (138 to 140 mM) or high (> 140 mM) dialysate [Na+] for maintenance HD patients were included.

DATA COLLECTION AND ANALYSIS

Two investigators independently screened studies for inclusion and extracted data. Statistical analyses were performed using random effects models, and results expressed as risk ratios (RR) for dichotomous outcomes, and mean differences (MD) or standardised MD (SMD) for continuous outcomes, with 95% confidence intervals (CI). Confidence in the evidence was assessed using GRADE.

MAIN RESULTS

We included 12 studies randomising 310 patients, with data available for 266 patients after dropout. All but one study evaluated a fixed concentration of low dialysate [Na+], and one profiled dialysate [Na+]. Three studies were parallel group, and the remaining nine cross-over. Of the latter, only two used a washout between intervention and control periods. Most studies were short-term with a median (interquartile range) follow-up of 3 (3, 8.5) weeks. Two were of a single HD session, and two of a single week's HD. Half of the studies were conducted prior to 2000, and five reported use of obsolete HD practices. Risks of bias in the included studies were often high or unclear, lowering confidence in the results.Compared to neutral or high dialysate [Na+], low dialysate [Na+] had the following effects on "efficacy" endpoints: reduced interdialytic weight gain (10 studies: MD -0.35 kg, 95% CI -0.18 to -0.51; high certainty evidence); probably reduced predialysis mean arterial blood pressure (BP) (4 studies: MD -3.58 mmHg, 95% CI -5.46 to -1.69; moderate certainty evidence); probably reduced postdialysis mean arterial BP (MAP) (4 studies: MD -3.26 mmHg, 95% CI -1.70 to -4.82; moderate certainty evidence); probably reduced predialysis serum [Na+] (7 studies: MD -1.69 mM, 95% CI -2.36 to -1.02; moderate certainty evidence); may have reduced antihypertensive medication (2 studies: SMD -0.67 SD, 95% CI -1.07 to -0.28; low certainty evidence). Compared to neutral or high dialysate [Na+], low dialysate [Na+] had the following effects on "safety" endpoints: probably increased intradialytic hypotension events (9 studies: RR 1.56, 95% 1.17 to 2.07; moderate certainty evidence); probably increased intradialytic cramps (6 studies: RR 1.77, 95% 1.15 to 2.73; moderate certainty evidence).Compared to neutral or high dialysate [Na+], low dialysate [Na+] may make little or no difference to: intradialytic BP (2 studies: MD for systolic BP -3.99 mmHg, 95% CI -17.96 to 9.99; diastolic BP 1.33 mmHg, 95% CI -6.29 to 8.95; low certainty evidence); interdialytic BP (2 studies:, MD for systolic BP 0.17 mmHg, 95% CI -5.42 to 5.08; diastolic BP -2.00 mmHg, 95% CI -4.84 to 0.84; low certainty evidence); dietary salt intake (2 studies: MD -0.21g/d, 95% CI -0.48 to 0.06; low certainty evidence).Due to very low quality of evidence, it is uncertain whether low dialysate [Na+] changed extracellular fluid status, venous tone, arterial vascular resistance, left ventricular mass or volumes, thirst or fatigue. Studies did not examine cardiovascular or all-cause mortality, cardiovascular events, or hospitalisation.

AUTHORS' CONCLUSIONS

It is likely that low dialysate [Na+] reduces intradialytic weight gain and BP, which are effects directionally associated with improved outcomes. However, the intervention probably also increases intradialytic hypotension and reduces serum [Na+], effects that are associated with increased mortality risk. The effect of the intervention on overall patient health and well-being is unknown. Further evidence is needed in the form of longer-term studies in contemporary settings, evaluating end-organ effects in small-scale mechanistic studies using optimal methods, and clinical outcomes in large-scale multicentre RCTs.

Predialysis hyponatremia and mortality in elderly patients beginning to undergo hemodialysis

BACKGROUND/AIMS

Predialysis hyponatremia has been recently reported to be associated with mortality in incident hemodialysis patients. However, whether hyponatremia is associated with unfavorable outcomes in elderly patients remains unknown. We hypothesized that nephrology referral inf luences hyponatremia, and aimed to define how nephrology referral affects the association between hyponatremia and mortality in the elderly.

METHODS

We retrospectively assessed mortality in 599 incident hemodialysis patients aged ≥ 70 at a tertiary university hospital, between 2000 and 2010. We analyzed 90-day and 1-year all-cause mortality (ACM) in relation to predialysis serum sodium (sNa). We divided the patients into two groups according to predialysis glucose-corrected sNa: hyponatremia (< 135 mmol/L) and normonatremia (135 to 145 mmol/L).

RESULTS

Low estimated glomerular filtration rate, high phosphorus, low albumin, nonpreparation of arteriovenous fistula or graft, and late referral were associated with a low sNa in the elderly. Among 599 patients, 106 and 174 patients died at the 90-day and 1-year follow-ups, respectively. Each 10-mmol/L increase in predialysis sNa tended to be associated with lower 90-day and 1-year ACM. When patients were stratified by nephrology referral, hyponatremia was associated with increased mortality in early referral group (90-day ACM: hazard ratio [HR] = 2.335, p = 0.041; 1-year ACM: HR = 1.790, p = 0.024). However, hyponatremia was not associated with mortality in late referral group.

CONCLUSION

Predialysis hyponatremia at hemodialysis initiation is associated with late referra.

Xerostomia, thirst, sodium gradient and inter-dialytic weight gain in hemodialysis diabetic vs. non-diabetic patients

Background

In hemodialysis (HD) patients, xerostomia and hyposalivation may intensify sensations of thirst, and contribute to the intake of fluids and excessive inter-dialytic weight gain (IWG). Since IWG is regarded to be higher in diabetic patients than in non-diabetics HD enhancing their mortality, it is crucial to define plausible underlying causes. Therefore, the study investigates factors contributing to the increased IWG in diabetic HD patients.

Material and Methods

The study included 97 HD patients (38 diabetics) receiving hemodialysis. All participants completed surveys comprising the Dialysis Thirst Inventory (DTI) and Xerostomia Inventory. Unstimulated whole saliva flow rate (USWFR) was measured, with USWFR below 0.1 mL/min being regarded as hyposalivation. Additionally, pre- and post-dialysis serum sodium concentration, sodium gradient and IWG were assessed. In diabetic HD patients, hemoglobin A1c (HbA1c) level was measured.

Results

Significantly higher scores were found in diabetic than non-diabetic HD patients with regard to DTI (21.2±7.7 vs. 17.1±6.2: Z=2.44, p=0.03) and xerostomia (40.5±6.1 vs. 29.9±14.4: Z=4.15, p=0.003). Hyposalivation was observed more often in diabetic HD patients (Z=2.23, p=0.04). IGW was significantly higher in participants with diabetes (Z=2.44, p=0.03), as was the pre-dialysis sodium serum (Z=3.4, p=0.008). High levels of HbA1c were associated with lower levels of serum sodium (r=-0.67 p<0.05). HbA1c positively correlated with pre-dialysis sodium gradient (r=0.66 p<0.05). However, multiple regression analysis found that the only predictors of increased IWG (>4.8 IWG%) in diabetic patients remained saliva flow rate and pre-dialysis sodium gradient.

Conclusions

Concomitant diabetes in hemodialysis patients appears to intensify subjective xerostomia and thirst sensation. It also leads to excessive IWG by the increase of pre-dialysis serum sodium gradient.

Key words:Diabetes mellitus, hemodialysis, hyposalivation, inter-dialytic weight gain, sodium gradient.

Hospitalizations in Dialysis Patients in Canada: A National Cohort Study

Background:

Hospitalizations of chronic dialysis patients have not been previously studied at a national level in Canada. Understanding the scope and variables associated with hospitalizations will inform measures for improvement.

Objective:

To describe the risk of all-cause and infection-related hospitalizations in patients on dialysis.

Design:

Retrospective cohort study using health care administrative databases.

Setting:

Provinces and territories across Canada (excluding Manitoba and Quebec).

Patients:

Incident chronic dialysis patients with a dialysis start date between January 1, 2005, and March 31, 2014. Patients with a prior history of kidney transplantation were excluded.

Measurements:

Patient characteristics were recorded at baseline. Dialysis modality was treated as a time-varying covariate. The primary outcomes of interest were all-cause and dialysis-specific infection-related hospitalizations.

Methods:

Crude rates for all-cause hospitalization and infection-related hospitalization were determined per patient year (PPY) at 7 and 30 days, and at 3, 6, and 12 months postdialysis initiation. A stratified, gamma-distributed frailty model was used to assess repeat hospital admissions and to determine the inter-recurrence dependence of hospitalizations within individuals, as well as the hazard ratio (HR) attributed to each covariate of interest.

Results:

A total of 38 369 incident chronic dialysis patients were included: 38 088 adults and 281 pediatric patients (age less than 18 years). There were 112 374 hospitalizations, of which 11.5% were infection-related hospitalizations. The all-cause hospitalization rate was similar for all adult age groups (age 65 years and older: 1.40, 1.35, and 1.18 admissions PPY at 7 days, 30 days, and 6 months, respectively). The all-cause hospitalization rate was higher for pediatric patients (1.67, 2.48, and 2.47 admissions PPY at 7 days, 30 days, and 6 months, respectively; adjusted HR: 2.73, 95% confidence interval [CI]: 2.37-3.15, referent age group: 45-64 years). Within the first 7 days after dialysis initiation, patients on peritoneal dialysis had a higher risk of all-cause hospitalization (HR: 1.27, 95% CI: 1.07-1.50) and infection-related hospitalization (HR: 2.05, 95% CI: 1.19-3.55) compared with patients on hemodialysis. Beyond 7 days, the risk did not differ significantly by dialysis modality. Female sex and Indigenous race were significant risk factors for all-cause hospitalization.

Limitations:

The cohort had too few home hemodialysis patients to examine this subgroup. The outcome of infection-related hospitalization was determined using diagnostic codes. Dialysis patients from Manitoba and Quebec were not included.

Conclusions:

In Canada, the rates of hospitalization were not influenced by dialysis modality beyond the initial 7-day period following dialysis initiation; however, the rate of hospitalization in pediatric patients was higher than in adults at every time frame examined.

Serum sodium and mortality in a national peritoneal dialysis cohort

Background

Sodium disarrays are common in peritoneal dialysis (PD) patients, and may be associated with adverse outcomes in this population. However, few studies of limited sample size have examined the association of serum sodium with mortality in PD patients, with inconsistent results. We hypothesized that both hypo- and hypernatremia are associated with higher death risk in a nationally representative cohort of US PD patients.

Methods

We sought to examine the association of serum sodium over time and mortality among 4687 adult incident PD patients from a large US dialysis organization who underwent one or more serum sodium measurements within the first 3 months of dialysis over January 2007 to December 2011. We examined the association of time-dependent and baseline sodium with all-cause mortality as a proxy of short- and long-term sodium-mortality associations, respectively. Hazard ratios were estimated using Cox models with three adjustment levels: minimally adjusted, case-mix adjusted, and case-mix + laboratory adjusted.

Results

In time-dependent analyses, sodium levels <140 mEq/L were associated with incrementally higher death risk in case-mix models (ref: 140 to <142 mEq/L); following laboratory covariate adjustment, associations between lower sodium and higher mortality remained significant for levels <136 mEq/L. In analyses using baseline values, sodium levels <140 mEq/L were associated with higher mortality risk across all models (ref: 140 to <142 mEq/L).

Conclusions

In PD patients, lower time-dependent and baseline sodium levels were independently associated with higher death risk. Further studies are needed to determine whether correction of dysnatremia improves longevity in this population.

Associations of dysnatremias with mortality in chronic kidney disease

Background

Hyponatremia and hypernatremia are associated with death in the general population and those with chronic kidney disease (CKD). We studied the associations between dysnatremias, all-cause mortality and causes of death in a large cohort of Stage 3 and 4 CKD patients.

Methods

We included 45 333 patients with Stage 3 and 4 CKDs followed in a large healthcare system. Associations between hyponatremia (<136 mmol/L) and hypernatremia (>145), and all-cause mortality and causes of death (cardiovascular, malignancy related and non-cardiovascular/non-malignancy related) were studied using Cox proportional hazards and competing risk models.

Results

Dysnatremias were found in 9.2% of the study population. In separate multivariable Cox proportional hazards models using baseline serum sodium levels and time-dependent repeated measures, both hyponatremia and hypernatremia were associated with all-cause mortality. In the competing risk analyses, hyponatremia was significantly associated with increased risk for various cause-specific mortality categories [cardiovascular (hazard ratio, HR 1.16, 95% confidence interval, CI: 1.04, 1.30), malignancy related (HR 1.48, 95% CI: 1.33, 1.65) and non-cardiovascular/non-malignancy deaths (HR 1.25, 95% CI: 1.13, 1.39)], while hypernatremia was significantly associated with higher non-cardiovascular/non-malignancy mortality only (HR 1.36, 95% CI: 1.08, 1.72).

Conclusions

In those with CKD, hyponatremia was associated with all-cause mortality, cardiovascular, malignancy and non-cardiovascular/non-malignancy-related deaths. Hypernatremia was associated with all-cause and non-cardiovascular/non-malignancy-related deaths. Further studies are needed to elucidate the mechanisms of differences in cause-specific death among CKD patients with hyponatremia and hypernatremia.

Hyponatremia and increased risk of dementia: A population-based retrospective cohort study

Hyponatremia is the most common electrolyte disorder and also a predictor of mild cognition impairment. However, the association between hyponatremia and dementia in long follow up periods is rarely investigated. A retrospective cohort study was performed using the claims data of all insured residents who were covered by Taiwan’s universal health insurance from 2000 to 2011. A total of 4900 hyponatremia patients and 19545 matched comparisons were recruited for the analysis. The incidences of hyponatremia and dementia were diagnosed with clinical protocol and defined using the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM). Cox proportional hazard regression and Kaplan–Meier curves were used for the analyses. Independent of adjusting factors, hyponatremia patients had 2.36-fold higher chances of suffering dementia, including Alzheimer’s disease (AD) and non-AD dementia, than the comparisons. Severe hyponatremia patients had higher risks of suffering dementia than the non-severe hyponatremia patients (adjusted hazard ratio: 4.29 (95% CI: 3.47–5.31) versus 2.08 (95% CI: 1.83–2.37)). A dose response relationship was observed between hyponatremia and dementia. Those hyponatremia patients with baseline or incident stroke had significantly higher chances of suffering dementia compared with those patients without hyponatremia and stroke. Stroke is a significant modifier of the relationship between hyponatremia and dementia. Cerebrovascular disease after incident hyponatremia must be prevented to reduce the incidence of dementia.

Copeptin Associates with Cause-Specific Mortality in Patients with Impaired Renal Function: Results from the LURIC and the 4D Study

BACKGROUND

In chronic kidney disease (CKD) arginine vasopressin (AVP) cannot efficiently act via renal V2-receptors. AVP is upregulated leading to augmented activation of V1a- and V1b-receptors, which might contribute to the increase in cardiovascular and infectious complications in CKD. Here, we evaluate copeptin, a surrogate of AVP, and its association with cause specific mortality among patients within the whole spectrum of renal function.

METHODS

Copeptin was measured in baseline samples from the LURIC (n = 3131 patients with coronary angiograms) and the 4D-Study (n = 1241 type 2 diabetic hemodialysis patients). Patients were stratified into 4 groups: estimated glomerular filtration rate (eGFR) ≥90 mL/min/1.73 m², 60-89 mL/min/1.73 m², <60 mL/min/1.73 m², and hemodialysis. The association of copeptin with mortality was assessed by Cox proportional hazards regression during 9.9 years of median follow-up in the Ludwigshafen Risk and Cardiovascular Health (LURIC) study and 4 years of median follow-up in the German Diabetes Dialysis Study (4D-Study).

RESULTS

Median copeptin increased with decreasing eGFR: 5.6 [interquartile range (IQR), 3.1-8.1] pmol/L (eGFR ≥90 mL/min/1.73 m²), 6.7 (2.9-10.5) pmol/L (eGFR 60-89 mL/min/1.73 m²), 15.3 (6.7-23.9) pmol/L (eGFR <60 mL/min/1.73 m²), and 80.8 (51.2-122) pmol/L (hemodialysis), respectively. Per SD increase in copeptin, the risk of coronary, infectious, and all-cause mortality increased by 25, 30, and 15% [hazard ratios (HR), 1.25; 95% CI, 1.13-1.39; HR, 1.30; 95% CI, 0.98-1.71; and HR, 1.15; 95% CI, 1.05-1.25], respectively, in patients with eGFR 60-89 mL/min/1.73 m². Except for coronary death, results were similar among patients with more advanced renal disease. No significant association was found in patients with normal renal function.

CONCLUSIONS

Copeptin concentrations were independently associated with coronary, infectious, and all-cause mortality in patients with renal impairment. In patients with normal renal function no significant association was found.

The Economic Burden of Hyponatremia: Systematic Review and Meta-Analysis

BACKGROUND

Hyponatremia is the most common electrolyte abnormality observed in clinical practice. Several studies have demonstrated that hyponatremia is associated with an increased length of hospital stay and of hospital resource utilization. To clarify the impact of hyponatremia on the length of hospitalization and costs, we performed a meta-analysis based on published studies that compared hospital length of stay and cost between patients with and without hyponatremia.

METHODS

An extensive Medline, Embase, and Cochrane search was performed to retrieve all studies published up to April 1, 2015 using the following words: "hyponatremia" or "hyponatraemia" AND "hospitalization" or "hospitalisation." A meta-analysis was performed including all studies comparing duration of hospitalization and hospital readmission rate in subjects with and without hyponatremia.

RESULTS

Of 444 retrieved articles, 46 studies satisfied the inclusion criteria, encompassing a total of 3,940,042 patients; among these, 757,763 (19.2%) were hyponatremic. Across all studies, hyponatremia was associated with a significantly longer duration of hospitalization (3.30 [2.90-3.71; 95% CIs] mean days; P < .000). Similar results were obtained when patients with associated morbidities were analyzed separately. Furthermore, hyponatremic patients had a higher risk of readmission after the first hospitalization (odds ratio 1.32 [1.18-1.48; 95% CIs]; P < .000). A meta-regression analysis showed that the hyponatremia-related length of hospital stay was higher in males (Slope = 0.09 [0.05-0.12; 95% CIs]; P = .000 and Intercept = -1.36 [-3.03-0.32; 95% CIs]; P = .11) and in elderly patients (Slope = 0.002 [0.001-0.003; 95% CIs]; P < .000 and Intercept = 0.89 [0.83-0.97; 95% CIs]; P < .001). A negative association between serum [Na(+)] cutoff and duration of hospitalization was detected. No association between duration of hospitalization, serum [Na(+)], and associated morbidities was observed. Finally, when only US studies (n = 8) were considered, hyponatremia was associated with up to around $3000 higher hospital costs/patient when compared with the cost of normonatremic subjects.

CONCLUSIONS

This meta-analysis confirms that hyponatremia is associated with a prolonged hospital length of stay and higher risk of readmission. These observations suggest that hyponatremia may represent one important determinant of the hospitalization costs.

Laboratory Profiles of Patients on Hemodialysis - A Retrospective One Year Study in a Rural Tertiary Care Hospital

INTRODUCTION

The global prevalence of chronic kidney disease (CKD) is estimated to be 8-16%. Studies have shown that the increased mortality in patients with CKD is due to anemia that leads to cardiovascular disease (CVD), also known as "Cardio renal anemia syndrome". The present study was undertaken to look into the laboratory profiles of end stage renal disease (ESRD) patients.

AIM

To study the laboratory profiles of End stage renal disease (ESRD) patients coming for hemodialysis.

MATERIALS AND METHODS

The study was a retrospective, cross- sectional study done by collecting data from the medical case records of all patients during a period of one year from January 1(st) 2014 to December 31(st) 2014. Records of a total of 140 patients who underwent hemodialysis during this period were taken. The laboratory profiles that was recorded included haemoglobin, serum sodium, potassium, chloride, fasting glucose, calcium and phosphorus.

RESULTS

The mean age of the subjects was 53.5±14.5 yrs. All the patients had moderate anaemia. There was a significant difference in the mean systolic and diastolic blood pressure, serum creatinine and serum urea values between males and females. The mean serum calcium levels were low.

CONCLUSION

The present study is the first such study in this rural area and shows evidence of a relatively young population with ESRD having moderate anaemia and hypertension. There is evidence of hypocalcaemia and serum phosphorus is on the higher end of the normal range. These findings are usually associated with a higher risk of mortality. With the explosion of diabetes and hypertension in India, chronic kidney disease should be diagnosed and managed as early as possible if not prevented.

Pre-dialysis serum sodium and mortality in a national incident hemodialysis cohort

BACKGROUND

A consistent association between low serum sodium measured at a single-point-in-time (baseline sodium) and higher mortality has been observed in hemodialysis patients. We hypothesized that both low and high time-varying sodium levels (sodium levels updated at quarterly intervals as a proxy of short-term exposure) are independently associated with higher death risk in hemodialysis patients.

METHODS

We examined the association of baseline and time-varying pre-dialysis serum sodium levels with all-cause mortality among adult incident hemodialysis patients receiving care from a large national dialysis organization during January 2007-December 2011. Hazard ratios were estimated using multivariable Cox models accounting for case-mix+laboratory covariates and incrementally adjusted for inter-dialytic weight gain, blood urea nitrogen and glucose.

RESULTS

Among 27 180 patients, a total of 7562 deaths were observed during 46 194 patient-years of follow-up. Median (IQR) at-risk time was 1.4 (0.6, 2.5) years. In baseline analyses adjusted for case-mix+laboratory results, sodium levels <138 mEq/L were associated with incrementally higher mortality risk, while the association of sodium levels ≥140 mEq/L with lower mortality reached statistical significance only for the highest level of pre-dialysis sodium (reference: 138-<140 mEq/L). In time-varying analyses, we observed a U-shaped association between sodium and mortality such that sodium levels <138 and ≥144 mEq/L were associated with higher mortality risk. Similar patterns were observed in models incrementally adjusted for inter-dialytic weight gain, blood urea nitrogen and glucose.

CONCLUSIONS

We observed a U-shaped association of time-varying pre-dialysis serum sodium and all-cause mortality in hemodialysis patients, suggesting that both hypo- and hypernatremia carry short-term risk in this population.

Hyponatremia Predicts New-Onset Cardiovascular Events in Peritoneal Dialysis Patients

Background and Aim

Cardiovascular (CV) disease is the leading cause of morbidity and mortality in patients on peritoneal dialysis (PD). Hyponatremia was recently shown to be a modifiable factor that is strongly associated with increased mortality in PD patients. However, the clinical impact of hyponatremia on CV outcomes in these patients is unclear.

Methods

To determine whether a low serum sodium level predicts the development of CV disease, we carried out a prospective observational study of 441 incident patients who started PD between January 2000 and December 2005. Time-averaged serum sodium (TA-Na) levels were determined to investigate the ability of hyponatremia to predict newly developed CV events in these patients.

Results

During a mean follow-up of 43.2 months, 106 (24.0%) patients developed new CV events. The cumulative incidence of new-onset CV events after the initiation of PD was significantly higher in patients with TA-Na levels ≤ 138 mEq/L than in those with a TA-Na > 138 mEq/L. After adjustment for multiple potentially confounding covariates, an increase in TA-Na level was found to be associated with a significantly lower risk of CV events (subdistribution hazard ratio per 1 mEq/L increase, 0.90; 95% confidence interval, 0.83–0.96; p = 0.003). Patients with a TA-Na ≤ 138 mEq/L had a 2.31-fold higher risk of suffering a CV event.

Conclusions

These results provide evidence of a clear association between low serum sodium and new-onset CV events after dialysis initiation in PD patients. Whether the correction of hyponatremia for this indication provides additional protection for the development of CV disease in these patients remains to be addressed in interventional studies.

Treatment of hyponatremic encephalopathy with a 3% sodium chloride protocol: a case series

BACKGROUND

3% sodium chloride solution is the accepted treatment for hyponatremic encephalopathy, but evidence-based guidelines for its use are lacking.

STUDY DESIGN

A case series.

SETTING & PARTICIPANTS

Adult patients presenting to the emergency department of a university hospital with hyponatremic encephalopathy, defined as serum sodium level < 130 mEq/L with neurologic symptoms of increased intracranial pressure without other apparent cause, and treated with a continuous infusion of 500mL of 3% sodium chloride solution over 6 hours through a peripheral vein.

PREDICTORS

Hyponatremic encephalopathy defined as serum sodium level < 130 mEq/L with neurologic symptoms of increased intracranial pressure without other apparent cause.

OUTCOMES

Change in serum sodium level within 48 hours, improvement in neurologic symptoms, and clinical evidence of cerebral demyelination, permanent neurologic injury, or death within 6 months' posttreatment follow-up.

RESULTS

There were 71 episodes of hyponatremic encephalopathy in 64 individuals. Comorbid conditions were present in 86% of individuals. Baseline mean serum sodium level was 114.1±0.8 (SEM) mEq/L and increased to 117.9±1.3, 121.2±1.2, 123.9±1.0, and 128.3±0.8 mEq/L at 3, 12, 24, and 48 hours following the initiation of 3% sodium chloride solution treatment, respectively. There was a marked improvement in central nervous system symptoms within hours of therapy in 69 of 71 (97%) episodes. There were 12 deaths, all of which occurred following the resolution of hyponatremic encephalopathy and were related to comorbid conditions, with 75% of deaths related to sepsis. No patient developed neurologic symptoms consistent with cerebral demyelination at any point during the 6-month follow-up period.

LIMITATIONS

Lack of a comparison group and follow-up neuroimaging studies. Number of cases is too small to provide definitive assessment of the safety of this protocol.

CONCLUSIONS

3% sodium chloride solution was effective in reversing the symptoms of hyponatremic encephalopathy in the emergency department without producing neurologic injury related to cerebral demyelination on long-term follow-up in this case series.

Hyponatremia as a predictor of mortality in peritoneal dialysis patients

BACKGROUND AND AIM

Hyponatremia is common in patients with chronic kidney disease and is associated with increased mortality in hemodialysis patients. However, few studies have addressed this issue in peritoneal dialysis (PD) patients.

METHODS

This prospective observational study included a total of 441 incident patients who started PD between January 2000 and December 2005. Using time-averaged serum sodium (TA-Na) levels, we aimed to investigate whether hyponatremia can predict mortality in these patients.

RESULTS

Among the baseline parameters, serum sodium level was positively associated with serum albumin (β = 0.145; p = 0.003) and residual renal function (RRF) (β = 0.130; p = 0.018) and inversely associated with PD ultrafiltration (β = -0.114; p = 0.024) in a multivariable linear regression analysis. During a median follow-up of 34.8 months, 149 deaths were recorded. All-cause death occurred in 81 (55.9%) patients in the lowest tertile compared to 37 (25.0%) and 31 (20.9%) patients in the middle and highest tertiles, respectively. After adjusting for multiple potentially confounding covariates, increased TA-Na level was associated with a significantly decreased risk of all-cause (HR per 1 mEq/L increase, 0.79; 95% CI, 0.73-0.86; p<0.001) and infection-related (HR per 1 mEq/L increase, 0.77; 95% CI, 0.70-0.85; p<0.001) deaths.

CONCLUSIONS

This study showed that hyponatremia is an independent predictor of mortality in PD patients. Nevertheless, whether correcting hyponatremia improves patient survival is unknown. Future interventional studies should address this question more appropriately.

Management of hyponatremia in various clinical situations

OPINION STATEMENT

Hyponatremia is the most common electrolyte abnormality in both inpatient and outpatient settings. The condition primarily results from the combination of impaired free water excretion due to elevated vasopressin levels in conjunction with a source of free water intake. Recent studies have revealed that even mild and asymptomatic hyponatremia is associated with deleterious consequences. It is an independent risk factor for mortality and is also associated with increased length of hospitalization and hospital costs. Even mild chronic hyponatremia can result in subtle neurologic impairment and bone demineralization, leading to falls and associated bone fractures in the elderly. Hyponatremia can be a difficult condition to treat, with varying therapeutic strategies based on the etiology, severity, duration, and extent of neurologic symptoms. The ideal magnitude of correction is also controversial, as both inadequate therapy and overly aggressive therapy can result in neurologic injury. Formulas that have been devised to aid in the treatment of hyponatremia can be inaccurate in that they fail to adequately account for the renal response to therapy. Hyponatremic encephalopathy is the most serious complication of hyponatremia, and can result in permanent neurologic impairment or death if left untreated. Individuals most at risk for developing hyponatremic encephalopathy are postmenarchal women, children under 16 years of age, patients with central nervous system disease or hypoxemia, and patients in the postoperative setting. The preferred therapy for hyponatremic encephalopathy is a 100-ml bolus of 3 % sodium chloride (513 mEq/L) administered in repeated doses until symptoms reverse, with the goal of increasing the serum sodium 5-6 mEq/L. Vasopressin (V2) antagonists (vaptans) are not appropriate for the management of acute hyponatremic encephalopathy, as the onset of action is not sufficiently rapid and the increase in sodium is not predictable. Vaptans are primarily indicated for the treatment of asymptomatic hyponatremia due to SIAD that is refractory to conventional measures.