Development and Validation of Equations to Estimate 24-H Urinary Sodium Excretion from Urine Samples of Patients with Chronic Kidney Disease

INTRODUCTION

The assessment of sodium intake is difficult due to low accuracy of dietary records and to the inconvenience of 24-h urine collections. Therefore, equations based on spot urine samples have been proposed to estimate sodium intake. In this study, we aimed to develop and to validate equations to estimate 24-h urinary sodium excretion (24hUNa) from several urine samples in chronic kidney disease (CKD) patients.

METHODS

Cross-sectional study with 76 CKD patients (males 55.3%; age: 64.5 [56.0-69.0] years; glomerular filtration rate 27.8 [24.7-32.1] mL/min). Sodium excretion was measured in 12-h daytime and 12-h nighttime collections; spot 1 (first urine of the day) and spot 2 (second urine of the day). By multivariable linear regression analysis, 4 equations were developed. The equations' accuracy was evaluated by P30 test. Association between estimated and measured 24hUNa was assessed by intraclass correlation coefficient (ICC); mean differences and limits of agreement by Bland-Altman plot. Data from 51 CKD patients of other CKD outpatient clinic were used to validate the equation developed from spot 2.

RESULTS

The 4 equations showed significant (p < 0.001) ICC and relatively good accuracy when compared to 24hUNa (Daytime: ICC = 0.89; P30 = 84%; Nighttime: ICC = 0.90; P30 = 83%; spot 1: ICC = 0.85; P30 = 78%; and spot 2: ICC = 0.70; P30 = 76%). In validation set, the equation from spot 2 was moderately accurate (P30 = 67%). Mean bias and ICC were 19.9 mmol/day and 0.58 (p = 0.001), respectively. A high sensitivity (97%) and specificity (89%) were found for a cutoff of 3.6 g of sodium/day.

CONCLUSION

Equations derived from 12 h collections better performed than spot urine when compared to gold standard 24hUNa. The equation from spot 2 showed good sensitivity to identify excessive sodium intake.

Anemia and iron deficiency among chronic kidney disease Stages 3-5ND patients in the Chronic Kidney Disease Outcomes and Practice Patterns Study: often unmeasured, variably treated

Background

International variation in anemia assessment and management practices in chronic kidney disease (CKD) is poorly understood.

Methods

We performed a cross-sectional analysis of anemia laboratory monitoring, prevalence and management in the prospective Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps). A total of 6766 participants with CKD Stages 3a–5ND from nephrology clinics in Brazil, France, Germany and the USA were included.

Results

Among patients with anemia (hemoglobin <12 g/dL), 36–58% in Brazil, the USA and Germany had repeat hemoglobin measured and 40–61% had iron indices measured within 3 months of the index hemoglobin measurement. Anemia was more common in the USA and Brazil than in France and Germany across CKD stages. Higher ferritin and lower iron saturation (TSAT) levels were observed with lower hemoglobin levels, and higher ferritin with more advanced CKD. The proportion of anemic patients with ferritin <100 ng/mL or TSAT <20% ranged from 42% in Brazil to 53% in France and Germany, and of these patients, over 40% in Brazil, Germany and the USA, compared with 27% in France, were treated with oral or intravenous iron within 3 months after hemoglobin measurement. The proportion of patients with hemoglobin <10 g/dL treated with erythropoiesis-stimulating agents ranged from 28% in the USA to 57% in Germany.

Conclusions

Hemoglobin and iron stores are measured less frequently than per guidelines. Among all regions, there was a substantial proportion of anemic patients with iron deficiency who were not treated with iron, highlighting an area for practice improvement in CKD care.

Identifying critically important vascular access outcomes for trials in haemodialysis: an international survey with patients, caregivers and health professionals

Background

Vascular access outcomes reported across haemodialysis (HD) trials are numerous, heterogeneous and not always relevant to patients and clinicians. This study aimed to identify critically important vascular access outcomes.

Method

Outcomes derived from a systematic review, multi-disciplinary expert panel and patient input were included in a multilanguage online survey. Participants rated the absolute importance of outcomes using a 9-point Likert scale (7–9 being critically important). The relative importance was determined by a best–worst scale using multinomial logistic regression. Open text responses were analysed thematically.

Results

The survey was completed by 873 participants [224 (26%) patients/caregivers and 649 (74%) health professionals] from 58 countries. Vascular access function was considered the most important outcome (mean score 7.8 for patients and caregivers/8.5 for health professionals, with 85%/95% rating it critically important, and top ranked on best–worst scale), followed by infection (mean 7.4/8.2, 79%/92% rating it critically important, second rank on best–worst scale). Health professionals rated all outcomes of equal or higher importance than patients/caregivers, except for aneurysms. We identified six themes: necessity for HD, applicability across vascular access types, frequency and severity of debilitation, minimizing the risk of hospitalization and death, optimizing technical competence and adherence to best practice and direct impact on appearance and lifestyle.

Conclusions

Vascular access function was the most critically important outcome among patients/caregivers and health professionals. Consistent reporting of this outcome across trials in HD will strengthen their value in supporting vascular access practice and shared decision making in patients requiring HD.

Considerable international variation exists in blood pressure control and antihypertensive prescription patterns in chronic kidney disease

Although blood pressure control is a major goal in chronic kidney disease, no worldwide overview of either its achievement or antihypertensive prescriptions is currently available. To evaluate this we compared crude prevalence of uncontrolled blood pressure among 17 cohort studies, including 34 602 individuals with estimated glomerular filtration rate under 60 ml/min/1.73 m² and treated hypertension across four continents, and estimated observed to expected prevalence ratios, adjusted for potential confounders. Crude prevalence of blood pressure of 140/90 mm Hg or more varied from 28% to 61% and of blood pressure of 130/80 or more from 54% to 84%. Adjusted prevalence ratios indicated poorer hypertension control than expected in cohorts from European countries, India, and Uruguay, and better control in patients from North American and high-income Asian countries. Four antihypertensive drug classes or more were prescribed to more than 30% of participants in North American and some European cohorts, but this practice was less common elsewhere. Renin angiotensin-aldosterone system inhibitors were the most common antihypertensive drugs, prescribed for 54% to 91% of cohort participants. Differences for other drug classes were much stronger, ranging from 11% to 79% for diuretics, 22% to 70% for beta-blockers, and 27% to 75% for calcium-channel blockers. The confounders studied explain only a part of the international variation in blood pressure control among individuals with chronic kidney disease. Thus, considerable heterogeneity in prescription patterns worldwide calls for further investigation into the impact of different approaches on patient outcomes.

Hydration Status and Kidney Health of Factory Workers Exposed to Heat Stress: A Pilot Feasibility Study

Dehydration associated with heat stress increases the risk of workplace injury or illness, decreases productivity, and may contribute to the chronic kidney disease epidemic identified in outdoor workers from hot climates. There is limited research on the effects of chronic occupational heat stress among indoor workers. We aimed to test the feasibility of measuring markers of hydration and kidney function in foundry factory workers in Southern Brazil, exposed and not exposed to heat stress. Factory workers exposed to heat stress (wet bulb globe temperature ≥28.9) and not exposed to heat were identified by management and invited to participate. Clinical and biochemical markers of hydration and kidney function were evaluated before and after a single 8.5 h work shift (lunch time not included). Feasibility outcomes included rates of enrolment, % completion of study protocols, and time to complete data collection. This study was deemed feasible with 80% enrolment and 90% completion of the protocol. Among the preselected workers, the enrolment rate was 91%. All subjects completed the physiological measures and blood collection and 95% completed the urine studies. Mean time to complete data collection pre-shift was 19.1 ± 4.2 min and post-shift: 14.3 ± 4.0 min. Workers exposed to heat stress had a greater decline in estimated glomerular filtration rate compared to controls over the work shift (–13 ± 11 vs. –5 ± 7 mL/min; p < 0.01). We demonstrated the feasibility and challenges of conducting future hydration and kidney function research among indoor factory workers. Further study is needed to determine if exposure to indoor heat contributes to a decline in kidney function.

Economic and quality of life burden of anemia on patients with CKD on dialysis: a systematic review

Aims: The overall cost and health-related quality of life (HRQoL) associated with current treatments for chronic kidney disease (CKD)-related anemia are not well characterized. A systematic literature review (SLR) was conducted on the costs and HRQoL associated with current treatments for CKD-related anemia among dialysis-dependent (DD) patients. Materials and methods: The authors searched the Cochrane Library, MEDLINE, EMBASE, NHS EED, and NHS HTA for English-language publications. Original studies published between January 1, 2000 and March 17, 2017 meeting the following criteria were included: adult population; study focus was CKD-related anemia; included results on patients receiving iron supplementation, red blood cell transfusion, or erythropoiesis stimulating agents (ESAs); reported results on HRQoL and/or costs. Studies which included patients with DD-CKD, did not directly compare different treatments, and had designs relevant to the objective were retained. HRQoL and cost outcomes, including healthcare resource utilization (HRU), were extracted and summarized in a narrative synthesis. Results: A total of 1,625 publications were retrieved, 15 of which met all inclusion criteria. All identified studies included ESAs as a treatment of interest. Two randomized controlled trials reported that ESA treatment improves HRQoL relative to placebo. Across eight studies comparing HRQoL of patients achieving high vs low hemoglobin (Hb) targets, aiming for higher Hb targets with ESAs generally led to modest HRQoL improvements. Two studies reported that ESA-treated patients had lower costs and HRU compared to untreated patients. One study found that aiming for higher vs lower Hb targets led to reduced HRU, while two other reported that this led to a reduction in cost-effectiveness. Limitations: Heterogeneity of study designs and outcomes; a meta-analysis could not be performed. Conclusions: ESA-treated patients undergoing dialysis incurred lower costs, lower HRU, and had better HRQoL relative to ESA-untreated patients. However, treatment to higher Hb targets led to modest HRQoL improvements compared to lower Hb targets.

An international Delphi survey helped develop consensus-based core outcome domains for trials in peritoneal dialysis

Shared decision-making about clinical care options in end-stage kidney disease is limited by inconsistencies in the reporting of outcomes and the omission of patient-important outcomes in trials. Here we generated a consensus-based prioritized list of outcomes to be reported during trials in peritoneal dialysis (PD). In an international, online, three-round Delphi survey, patients/caregivers and health professionals rated the importance of outcomes using a 9-point Likert scale (with 7-9 indicating critical importance) and provided comments. Using a Best-Worst Scale (BWS), the relative importance of outcomes was estimated. Comments were analyzed thematically. In total, 873 participants (207 patients/caregivers and 666 health professionals) from 68 countries completed round one, 629 completed round two and 530 completed round three. The top outcomes were PD-related infection, membrane function, peritoneal dialysis failure, cardiovascular disease, death, catheter complications, and the ability to do usual activities. Compared with health professionals, patients/caregivers gave higher priority to six outcomes: blood pressure (mean difference, 0.4), fatigue (0.3), membrane function (0.3), impact on family/friends (0.1), peritoneal thickening (0.1) and usual activities (0.1). Four themes were identified that underpinned the reasons for ratings: contributing to treatment longevity, preserving quality of life, escalating morbidity, and irrelevant and futile information and treatment. Patients/caregivers and health professionals gave highest priority to clinical outcomes. In contrast to health professionals, patients/caregivers gave higher priority to lifestyle-related outcomes including the impact on family/friends and usual activities. Thus, prioritization will inform a core outcome set to improve the consistency and relevance of outcomes for trials in PD.

Impact of Glucose Exposure on Outcomes of a Nation-Wide Peritoneal Dialysis Cohort - Results of the BRAZPD II Cohort

Background: Data investigating the association of glucose exposure with technique failure and patient survival are limited to retrospective cohorts and was never tested outside Asia and considering the presence of competing risks.

Methods: Prospective multicenter cohort study of incident peritoneal dialysis patients where the association of cumulative glucose exposure in 6, 12, and 24 months with patient survival and technique failure was tested using Cox regression analysis and competing risk analysis.

Results: We analyzed 4367 incident peritoneal dialysis patients with mean age 59.0 ± 15.8 years, 43.9% were diabetics, 46.7% males and 64.4% Caucasians. Glucose exposure was not associated with patient survival independent of the time of exposure and even after adjustments for confounders. In contrast, higher glucose exposure was associated with more technique failure in the Cox and competing risk models. The higher risk for technique failure was found in the subgroup exposed to the higher amount of glucose to a maximum of 86% in the model analyzing cumulative glucose exposure for 1 year.

Conclusion: Glucose exposure was associated with technique failure but not with patient survival.

Design and methodology of the impact of HemoDiaFIlTration on physical activity and self-reported outcomes: a randomized controlled trial (HDFIT trial) in Brazil

BACKGROUND

End stage renal disease (ESRD) patients require a renal replacement therapy (RRT) to filter accumulated toxins and remove excess water, which are associated with impaired physical function. Hemodialysis (HD) removes middle-molecular weight (MMW) toxins less efficiently compared to hemodiafiltration (HDF); we hypothesized HDF may improve physical function. We detailed the design and methodology of the HDFIT protocol that is testing whether changing from HD to HDF effects physical activity levels and various outcomes.

METHODS

HDFIT is a prospective, multi-center, unblinded, randomized control trial (RCT) investigating the impact of dialysis modality (HDF verses HD) on objectively measured physical activity levels, self-reported quality of life, and clinical/non-clinical outcomes. Clinically stable patients with HD vintage of 3 to 24 months without any severe limitation ambulation were recruited from sites throughout southern Brazil. Eligible patients were randomized in a 1:1 ratio to either: 1) be treated with high volume online HDF for 6 months, or 2) continue being treated with high-flux HD. This study includes run-in and randomization visits (baseline), 3- and 6-month study visits during the interventional period, and a 12-month observational follow up. The primary outcome is the difference in the change in steps per 24 h on dialysis days from baseline to the 6-month follow up in patients treated with HDF versus HD. Physical activity is being measured over one week at study visits with the ActiGraph ( www.actigraphcorp.com ). For assessment of peridialytic differences during the dialysis recovery period, we will analyze granular physical activity levels based on the initiation time of HD on dialysis days, or concurrent times on non-dialysis days and the long interdialytic day.

DISCUSSION

In this manuscript, we provide detailed information about the HDFIT study design and methodology. This trial will provide novel insights into peridialytic profiles of physical activity and various self-reported, clinical and laboratory outcomes in ESRD patients treated by high volume online HDF versus high-flux HD. Ultimately, this investigation will elucidate whether HDF is associated with patients having better vitality and quality of life, and less negative outcomes as compared to HD.

TRIAL REGISTRATION

Registered on ClinicalTrials.gov on 20 April 2016 ( NCT02787161 ).

Inhibition of the sodium-glucose co-transporter 2 in the elderly: clinical and mechanistic insights into safety and efficacy

The prevalence of type 2 diabetes mellitus (T2DM) in the elderly grew sharply over the last decade. Reduced insulin sensitivity and secretory capacity, weight gain, sarcopenia, and elevated adiposity are all common metabolic and body changes in the aging population that favor an increased risk of hypoglycemia, frailty syndrome, falls, and cognitive dysfunction. First line antidiabetic therapy is frequently not safe in older individuals because of its high risk of hypoglycemia and prevalent co-morbid diseases, such as chronic kidney disease, osteoporosis, cardiovascular disease, and obesity. Sodium-glucose cotransporter 2 inhibitor (SGLT2i) is a new class of antidiabetic therapy that inhibits glucose and sodium reabsorption on renal proximal convoluted tubule. Its effect is well demonstrated in various clinical scenarios in the younger population. This review and metanalysis describe particularities of the SGLT2i on the elderly, with mechanistic insights of the potential benefit and remaining challenges about the use of these drugs in this important age group. Further, we will present a meta-analysis of the main effects of SGLT2i reported in post-hoc studies in which the median age of the subgroups analyzed was over 60 years. Despite the absence of specific clinical trials for this population, our findings suggest that SGLT2i therapy on older individuals is effective to lower glucose and maintain its effect on systolic blood pressure and body weight.

Low-Fiber Intake Is Associated With High Production of Intraperitoneal Inflammation Biomarkers

OBJECTIVE

Fiber intake influences disturbances in the gastrointestinal tract and is associated with systemic inflammation in the general population. Systemic and intraperitoneal inflammation play an important role in defining outcomes in peritoneal dialysis (PD), but the relationship between dietary fiber intake and inflammatory biomarkers has not yet been reported in the population on PD. The objective of the present study is to analyze whether or not fiber intake in patients on PD is associated with serum and intraperitoneal levels of inflammatory biomarkers.

DESIGN AND METHODS

Adult and clinically stable PD patients were included in this observational and cross-sectional study. Fiber intake was assessed by means of a dietary survey and calculated using the DietPro program 5.6i. The population was divided into two groups according to the median fiber intake. We investigated interleukin (IL)-1β, IL-6, tumor necrosis factor-α, monocyte chemoattractant protein-1 (MCP-1), B-cell-activating factor, and plasminogen-activator inhibitor-1 in both serum and peritoneal fluid. The latter was determined after a dwell time of 4 hours.

RESULTS

Fifty-two patients (42% men; aged 53 ± 14 years, 36% diabetics) were evaluated. Low intake of dietary fiber was found in 90% of patients, with a median of 12.2 g per day (3.4-33.3). The group with the highest fiber intake presented lower intraperitoneal levels of IL-6, IL-8, and MCP-1. In contrast, only MCP-1 was lower in the serum of those who consumed more fiber. All the associations remained significant after adjustment for confounders with plasminogen-activator inhibitor-1 included.

CONCLUSIONS

Patients on PD frequently present inadequate dietary fiber intake, which appears to have an association with the inflammatory response, particularly in the intraperitoneal component. Further prospective studies, evaluating whether or not a dietetic intervention with a focus on fiber intake affects these biomarkers and clinical outcomes, are essential to determine causality and clinical relevance.

Patient and Caregiver Priorities for Outcomes in Peritoneal Dialysis: Multinational Nominal Group Technique Study

BACKGROUND AND OBJECTIVES

The absence of accepted patient-centered outcomes in research can limit shared decision-making in peritoneal dialysis (PD), particularly because PD-related treatments can be associated with mortality, technique failure, and complications that can impair quality of life. We aimed to identify patient and caregiver priorities for outcomes in PD, and to describe the reasons for their choices.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients on PD and their caregivers were purposively sampled from nine dialysis units across Australia, the United States, and Hong Kong. Using nominal group technique, participants identified and ranked outcomes, and discussed the reasons for their choices. An importance score (scale 0-1) was calculated for each outcome. Qualitative data were analyzed thematically.

RESULTS

Across 14 groups, 126 participants (81 patients, 45 caregivers), aged 18-84 (mean 54, SD 15) years, identified 56 outcomes. The ten highest ranked outcomes were PD infection (importance score, 0.27), mortality (0.25), fatigue (0.25), flexibility with time (0.18), BP (0.17), PD failure (0.16), ability to travel (0.15), sleep (0.14), ability to work (0.14), and effect on family (0.12). Mortality was ranked first in Australia, second in Hong Kong, and 15th in the United States. The five themes were serious and cascading consequences on health, current and impending relevance, maintaining role and social functioning, requiring constant vigilance, and beyond control and responsibility.

CONCLUSIONS

For patients on PD and their caregivers, PD-related infection, mortality, and fatigue were of highest priority, and were focused on health, maintaining lifestyle, and self-management. Reporting these patient-centered outcomes may enhance the relevance of research to inform shared decision-making.

Diagnostic performance of salivary urea nitrogen dipstick to detect and monitor acute kidney disease in patients with malaria

Background

Acute kidney injury (AKI) is a common complication of malaria. In low resource settings, a lack of diagnostic tools and delayed treatment of malaria associated AKI lead to significant morbidity and mortality. The aim of this study was to assess the diagnostic performance of salivary urea nitrogen (SUN) dipstick to detect and monitor kidney disease [KD = AKI or acute kidney disease (AKD) without AKI] in malaria patients in Angola.

Methods

Patients 11–50 years old admitted with malaria at the Josina Machel (Maria-Pia) Hospital, Luanda, Angola, between 2nd March and 10th May 2016 were enrolled in this study. All participants had serum creatinine (sCr), blood urea nitrogen (BUN) and SUN dipstick tested at the time of recruitment and daily for up to 4 days. AKD without AKI refers to acute renal impairment which do not fulfilled the main criteria for AKI (increases in the baseline serum creatinine and/or decreases in urine output) according defined by the kidney disease improving global outcomes (KDIGO) guideline.

Results

Eight-six patients were admitted with malaria diagnosis (mean age 21.5 ± 9.4 years, 71% male) and 27 (32%) were diagnosed with KD. The mean (± SD) sCr and BUN of the KD group at admission (day 0) were 5.38 (± 5.42) and 99.4 (± 61.9) mg/dL, respectively. Three (3.5%) patients underwent haemodialysis and eight (9.3%) died within the first 4 days of hospital admission [5 (62.5%) with KD; 3 (37.5%) without kidney disease; p = 0.047]. The SUN threshold for KD diagnosis was tested pad #5 (SUN > 54 mg/dL). At this threshold, the SUN dipstick had a sensitivity of 67% and specificity of 98% to diagnose KD. The area under the receiver operating characteristics curve (ROC) for KD diagnosis on admission was 0.88 (95% CI 0.79–0.96). The SUN dipstick was most accurate at higher levels of BUN.

Conclusion

The SUN dipstick had reasonable sensitivity and excellent specificity when used to diagnose KD in a cohort of patients with malaria in a resource-limited setting. Given the severity of presenting illness and kidney injury, the SUN dipstick diagnostic threshold was high (test pad #5). SUN may be used to detect AKI in patients with malaria in low resources settings, thus facilitating earlier access to adequate treatment, which may improve survival.

Electronic supplementary material

The online version of this article (10.1186/s12936-018-2627-4) contains supplementary material, which is available to authorized users.

Hypertension in patients on dialysis: diagnosis, mechanisms, and management

Hypertension (blood pressure > 140/90 mm Hg) is very common in patients undergoing regular dialysis, with a prevalence of 70-80%, and only the minority has adequate blood pressure (BP) control. In contrast to the unclear association of predialytic BP recordings with cardiovascular mortality, prospective studies showed that interdialytic BP, recorded as home BP or by ambulatory blood pressure monitoring in hemodialysis patients, associates more closely with mortality and cardiovascular events. Although BP is measured frequently in the dialysis treatment environment, aspects related to the measurement technique traditionally employed may be unsatisfactory. Several other tools are now available and being used in clinical trials and in clinical practice to evaluate and treat elevated BP in chronic kidney disease (CKD) patients. While we wait for the ongoing review of the CKD Blood Pressure KIDGO guidelines, there is no guideline for the dialysis population addressing this important issue. Thus, the objective of this review is to provide a critical analysis of the information available on the epidemiology, pathogenic mechanisms, and the main pillars involved in the management of blood pressure in stage 5-D CKD, based on current knowledge.

A Cross-Sectional Study of Growth and Metabolic Bone Disease in a Pediatric Global Cohort Undergoing Chronic Hemodialysis

OBJECTIVE

We sought to assess worldwide differences among pediatric patients undergoing hemodialysis. Because practices differ widely regarding nutritional resources, treatment practice, and access to renal replacement therapy, investigators from the Pediatric Investigation and Close Collaboration to examine Ongoing Life Outcomes, the pediatric subset of the MONitoring Dialysis Outcomes Cohort (PICCOLO MONDO) performed this cross-sectional study. We hypothesized that growth would be better in developed countries, possibly at the expense of bone mineral disease.

STUDY DESIGN

In this cross-sectional study, we analyzed growth by height z score and recommended age-specific bone mineral metabolism markers from 225 patients <18 years of age maintained on hemodialysis, between the years of 2000 to 2012 from 21 countries in different regions.

RESULTS

The patients' median age was 16 (IQR 14-17) years, and 45% were females. A height z score less than the third percentile was noted in 34% of the cohort, whereas >66% of patients reported normal heights, with patients from North America having the greatest proportion (>80%). More than 70% of the entire cohort had greater than the age-recommended levels of phosphorus, particularly in the Asia-Pacific and North America, where we also observed the greatest body mass index z score (0.99 ± 1.6) and parathyroid hormone levels (557.1 [268.4-740.5]). Below-recommended parathyroid hormone levels were noted in 26% and elevated levels in 61% of the entire sample, particularly in the Asia Pacific region. Lower-than-recommended calcium levels were noted in 36% of the entire cohort, particularly in Latin America.

CONCLUSIONS

We found regional differences in growth- and age-adjusted bone mineral metabolism markers. Children from North America had the best growth, received the most dialysis, but also had the worst phosphate control and body mass index z scores.

Uremia Impacts VE-Cadherin and ZO-1 Expression in Human Endothelial Cell-to-Cell Junctions

Endothelial dysfunction in uremia can result in cell-to-cell junction loss and increased permeability, contributing to cardiovascular diseases (CVD) development. This study evaluated the impact of the uremic milieu on endothelial morphology and cell junction’s proteins. We evaluated (i) serum levels of inflammatory biomarkers in a cohort of chronic kidney disease (CKD) patients and the expression of VE-cadherin and Zonula Occludens-1 (ZO-1) junction proteins on endothelial cells (ECs) of arteries removed from CKD patients during renal transplant; (ii) ECs morphology in vitro under different uremic conditions, and (iii) the impact of uremic toxins p-cresyl sulfate (PCS), indoxyl sulfate (IS), and inorganic phosphate (Pi) as well as of total uremic serum on VE-cadherin and ZO-1 gene and protein expression in cultured ECs. We found that the uremic arteries had lost their intact and continuous endothelial morphology, with a reduction in VE-cadherin and ZO-1 expression. In cultured ECs, both VE-cadherin and ZO-1 protein expression decreased, mainly after exposure to Pi and uremic serum groups. VE-cadherin mRNA expression was reduced while ZO-1 was increased after exposure to PCS, IS, Pi, and uremic serum. Our findings show that uremia alters cell-to-cell junctions leading to an increased endothelial damage. This gives a new perspective regarding the pathophysiological role of uremia in intercellular junctions and opens new avenues to improve cardiovascular outcomes in CKD patients.

Peritonitis as a risk factor for long-term cardiovascular mortality in peritoneal dialysis patients: The case of a friendly fire?

AIM

Since the impact of peritonitis on long-term non-infectious mortality has not been investigated until the present, the aim of this study was to analyze the impact of peritonitis on long-term cardiovascular (CV) mortality in a large peritoneal dialysis (PD) cohort.

METHODS

The analysis was based on BRAZPD II, a national prospective cohort study that recruited patients in Brazilian centres from December 2004 to January 2011. Incident adult PD patients with at least 90 days on treatment were included in the analysis. Cardiovascular death occurring after a minimum of 30 days after a peritonitis episode was considered the primary endpoint. Cox regression analysis for time-dependent variables was used for the adjustments.

RESULTS

There were 2405 episodes of peritonitis in 5707 patients (48% males, 44% diabetes, 73% hypertensive). Patients with one episode of peritonitis presented a 22% increase in the hazard ratio of late CV mortality compared to those who never experienced peritonitis (HR1.22; CI95%1.01-1.47). Adjusted hazard for CV mortality showed a stepwise negative effect on survival for each additional peritonitis episode of infection: two episodes (HR1.78; CI95%1.31-2.42), three episodes (HR2.81; CI95%1.83-4.32) and four episodes (HR3.84; CI95%2.01-7.32).

CONCLUSION

Peritonitis was an independent predictor of CV mortality and the frequency of peritonitis was strongly associated with an increase in this risk. This is the first study to demonstrate the impact of peritonitis on late cardiovascular mortality of PD patients, suggesting a link between acute inflammation and cardiovascular outcomes.