Reduced plasma zinc levels, lipid peroxidation, and inflammation biomarkers levels in hemodialysis patients: implications to cardiovascular mortality

Inflammation and all-cause mortality in patients undergoing peritoneal dialysis

OBJECTIVE

This study aimed to evaluate inflammatory biomarkers in patients undergoing peritoneal dialysis and investigate their association with all-cause mortality or transfer to hemodialysis.

METHODS

This prospective cohort study included 43 patients undergoing peritoneal dialysis. Plasma levels of cytokines were measured using flow cytometry and capture enzyme-linked immunosorbent assay. Biomarkers were categorized based on their respective median values. Survival analysis was conducted using the Kaplan-Meier estimator, considering two outcomes: all-cause mortality and transfer to hemodialysis.

RESULTS

After adjusting for confounding factors, plasma levels above the median of the levels of CCL2 and plasma, as well as below the median of TNF-α, and the median of dialysate IL-17 levels, were associated with an increased risk of experiencing the specified outcomes after approximately 16 months of follow-up.

CONCLUSION

These findings suggest that inflammatory biomarkers may be a valuable tool for predicting all-cause mortality and transfer to hemodialysis in patients undergoing peritoneal dialysis.

Serum Zinc and Copper Concentrations and Dyslipidemia as Risk Factors of Cardiovascular Disease in Adults: Data Mining Techniques

This study aimed to examine the relationship between serum cholesterol levels and the ratio of zinc (Zn) and copper (Cu) in the blood serum and the incidence of cardiovascular disease (CVD). In Phase I of the study, 9704 individuals between the age of 35 and 65 years were recruited. Phase II of the cohort study comprised 7561 participants who completed the 10-year follow-up. The variables which were measured at the baseline of the study included gender, age, systolic blood pressure (SBP), diastolic blood pressure (DBP); biochemical parameters including serum Cu, Zn, copper-zinc ratio (Cu/Zn), zinc-copper ratio (Zn/Cu); fasted lipid profile consisting of triglycerides (TG), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL) as well as fasting serum glucose, and triglycerides-glucose (TyG) index. Decision tree (DT) and logical regression (LR) models were applied to examine the relationship between the aforementioned factors and CVD. CVD was diagnosed in 837 individuals (378 males and 459 females) out of 7561 participants. According to the LR models, SBP, TC, HDL, age, Zn/Cu, and TyG index for males and SBP, age, TyG index, HDL, TC, Cu/Zn, and Cu for females had the highest correlation with CVD (p-value ≤ 0.033). Based on the DT algorithm, 88% of males with SPB < 129.66 mmHg, younger age (age < 53 years), TyG index < 9.53, 173 ≤ TC < 187 mg/dL, and HDL ≥ 32 mg/dL had the lowest risk of CVD. Also, 98% of females with SBP < 128 mmHg, TyG index < 9.68, age < 44, TC < 222 mg/dL, and HDL ≥ 63.7 mg/dL had the lowest risk of CVD. It can be concluded that the Zn/Cu for men and Cu/Zn for women, along with dyslipidemia and SBP, could significantly predict the risk of CVD in this cohort from northeastern Iran.

Trace Elements Status and Their Associations With Related Antioxidant Enzyme Activities in Patients Receiving Peritoneal Dialysis and Hemodialysis

OBJECTIVE

It remains ambiguous as to whether the status of trace elements would affect their related enzyme activities toward defending a possible higher oxidative stress in patients receiving peritoneal dialysis (PD) or hemodialysis (HD) treatment. We investigated copper (Cu), zinc (Zn), and selenium (Se) status in patients receiving PD or HD treatments and further determined the association of these trace elements with their related antioxidant capacities in those patients.

METHODS

Sixty PD and 80 HD patients before and after HD treatment had their blood drawn. Demographic, clinical, and 24-hour diet recall data were recorded and collected. Plasma trace elements, oxidative stress indicators, and antioxidant enzyme activities were measured.

RESULTS

Patients receiving PD or HD treatments experienced similar Zn and Cu intakes. PD and HD patients displayed adequate mean plasma Cu, Zn, and Se levels. Patients receiving PD treatment showed significantly higher levels of Cu, Zn, advanced oxidation protein products (AOPPs), and superoxide dismutase (SOD) activity, but had significantly lower levels of Se and total antioxidant capacity when compared to levels in the HD patients at the pre-HD session. The levels of 3 trace elements and AOPP increased significantly, while the levels of glutathione (GSH), oxidized glutathione (GSSG), GPx, and SOD activities decreased significantly after receiving HD treatment than did the levels in the pre-HD session. Plasma Cu, Se, and Zn levels had a different correlation with plasma AOPP level, GPx, and SOD activities during PD, pre- or post-HD sessions. Plasma Cu, Zn, and Se levels did not have any association with their associated enzyme activities in patients with PD, while plasma Cu and Zn levels may have influenced SOD activity in HD patients.

CONCLUSIONS

An adequate Cu, Zn, and Se status is required in order to help their associated enzyme activity cope with increased oxidative stress during PD or HD sessions.

Estimating the association between systemic Interleukin-6 and mortality in the dialysis population. Re-analysis of the global fluid study, systematic review and meta-analysis

BACKGROUND

Systemic inflammation, measured as circulating Interleukin-6 (IL-6) levels, is associated with cardiovascular and all-cause mortality in chronic kidney disease. However, this has not been convincingly demonstrated in a systematic review or a meta-analysis in the dialysis population. We provide such evidence, including a re-analysis of the GLOBAL Fluid Study.

METHODS

Mortality in the GLOBAL fluid study was re-analysed using Cox proportional hazards regression with IL-6 levels as a covariate using a continuous non-logarithmic scale. Literature searches of the association of IL-6 levels with mortality were conducted on MEDLINE, EMBASE, PyschINFO and CENTRAL. All studies were assessed for risk of bias using the QUIPS tool. To calculate a pooled effect size, studies were grouped by use of IL-6 scale and included in the meta-analysis if IL-6 was analysed as a continuous linear covariate, either per unit or per 10 pg/ml, in both unadjusted or adjusted for other patient characteristics (e.g. age, comorbidity) models. Funnel plot was used to identify potential publication bias.

RESULTS

Of 1886 citations identified from the electronic search, 60 were included in the qualitative analyses, and 12 had sufficient information to proceed to meta-analysis after full paper screening. Random effects meta-analysis of 11 articles yielded a pooled hazard ratio (HR) per pg/ml of 1.03, (95% CI 1.01, 1.03), [Formula: see text]= 81%. When the analysis was confined to seven articles reporting a non-adjusted HR the result was similar: 1.03, per pg/ml (95% CI: 1.03, 1.06), [Formula: see text]=92%. Most of the heterogeneity could be attributed to three of the included studies. Publication bias could not be determined due to the limited number of studies.

CONCLUSION

This systematic review confirms the adverse association between systemic IL-6 levels and survival in people treated with dialysis. The heterogeneity that we observed may reflect differences in study case mix.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO - CRD42020214198.

Interleukin-6 levels can be used to estimate cardiovascular and all-cause mortality risk in dialysis patients: A meta-analysis and a systematic review

BACKGROUND

Although previous studies have explored the correlation of interleukin (IL)-6 with mortality risk in dialysis patients, the findings have been conflicting. Hence, this meta-analysis aimed to comprehensively assess the use of IL-6 measurement for estimating cardiovascular mortality and all-cause mortality in dialysis patients.

METHODS

The Embase, PubMed, Web of Science, and MEDLINE databases were searched to identify relevant studies. After screening out the eligible studies, the data were extracted.

RESULTS

Twenty-eight eligible studies with 8370 dialysis patients were included. Pooled analyses revealed that higher IL-6 levels were related to increased cardiovascular mortality risk (hazard ratio [HR] = 1.55, 95% confidence interval [CI]: 1.20-1.90) and all-cause mortality risk (HR = 1.11, 95% CI: 1.05-1.17) in dialysis patients. Further subgroup analyses suggested that higher IL-6 levels were associated with elevated cardiovascular mortality in hemodialysis patients (HR = 1.59, 95% CI: 1.36-1.81) but not in peritoneal dialysis patients (HR = 1.56, 95% CI: 0.46-2.67). Moreover, sensitivity analyses indicated that the results were robust. Egger's test revealed potential publication bias among studies exploring the correlation of IL-6 levels with cardiovascular mortality (p = .004) and all-cause mortality (p < .001); however, publication bias was not observed when using Begg's test (both p > .05).

CONCLUSIONS

This meta-analysis reveals that higher IL-6 levels could indicate higher risks of cardiovascular mortality and all-cause mortality in dialysis patients. These findings suggest that monitoring IL-6 cytokine may help to enhance dialysis management and improve the general prognosis of patients.

Clinical Significance of Trace Element Zinc in Patients with Chronic Kidney Disease

The trace element zinc is essential for diverse physiological processes in humans. Zinc deficiency can impair growth, skin reproduction, immune function, maintenance of taste, glucose metabolism, and neurological function. Patients with chronic kidney disease (CKD) are susceptible to zinc deficiency, which is associated with erythropoiesis-stimulating agent (ESA) hypo-responsive anemia, nutritional problems, and cardiovascular diseases as well as non-specific symptoms such as dermatitis, prolonged wound healing, taste disturbance, appetite loss, or cognitive decline. Thus, zinc supplementation may be useful for the treatment of its deficiency, although it often causes copper deficiency, which is characterized by several severe disorders including cytopenia and myelopathy. In this review article, we mainly discuss the significant roles of zinc and the association between zinc deficiency and the pathogenesis of complications in patients with CKD.

Do trace elements play a role in coronary artery calcification in hemodialysis patients?

PURPOSE

Abnormalities of trace elements have previously been linked to inflammatory processes in hemodialysis (HD) patients. We aimed to establish the trace element status of maintenance HD patients, to investigate the relationship between coronary artery calcification scores (CACs) and whole blood levels of trace elements.

METHODS

Patients undergoing HD in three times a week for > 6 months and age-and sex-matched controls were included from October 2015 to June 2016. Data were collected from patient files. All subjects' whole blood levels of trace elements were measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). CACs for patients were assessed by multi-detector computed tomography.

RESULTS

The 35 patients (male, 60%) with a mean age of 45.7 ± 10.4 years and 35 controls were included. HD patients showed significantly lower levels of selenium and uranium and higher cadmium (Cd), cobalt, lithium, manganese, nickel, lead, platinum, tin, strontium, and thallium levels compared to controls. Coronary artery calcification (CAC) was present in 21 patients (60%), and median CACs were 14.2 (IQR 0-149). Patients with CACs > median were significantly older, had a higher prevalence of hypertension and lower ALP levels than patients with CACs ≤ median. No significant differences in whole blood levels of trace elements were found between patients with CACs > median and patients with CACs ≤ median. A near significance was noted in median whole blood levels of Cd between these groups (P = 0.096). According to multivariate analysis, age was the only independent determinant for CAC development.

CONCLUSION

Age is independently associated with coronary vascular calcification. High Cd levels might play a role in CAC development in HD patients.

Serum Zinc Levels in Chronic Kidney Disease Patients, Hemodialysis Patients, and Healthy Controls: Systematic Review and Meta-Analysis

OBJECTIVES

Patients with chronic kidney disease (CKD) are susceptible to changes in zinc homeostasis through anorexia and dietary restrictions, as well as hemodialysis (HD). Changes in zinc homeostasis might predispose CKD and HD patients to specific adverse effects, including erythropoietin-resistant anemia, oxidative stress, atherosclerosis, and cardiovascular disease. Because serum zinc levels are rarely measured in CKD and HD patients, zinc supplementations do not represent a routine therapy for CKD and dialysis patients. Therefore, in this meta-analysis, we aimed to assess serum zinc levels in CKD and HD patients compared with healthy controls (HC). In addition, we investigated whether HD affects serum zinc levels by comparing serum zinc levels in HD versus CKD patients and comparing serum zinc pre- versus post-HD.

DESIGN AND METHODS

A comprehensive search of databases was conducted to identify either observational studies or randomized trials that assessed serum zinc levels in either CKD and/or HD patients in comparison to HC. We conducted a random-effects meta-analysis.

RESULTS

Our meta-analysis included 42 studies with a total of 4,161 participants, of whom 460 were CKD patients, 2,047 were HD patients, and 1,654 were HCs. Both CKD and HD patients showed lower serum zinc levels compared with HC (mean difference = -22.86 μg/dL, 95% CI -33.25 to -12.46; mean difference = -13.64 μg/dL, 95% CI -21.47 to -53.80, respectively). CKD and HD patients showed no significant difference in serum zinc levels (mean difference = 15.39, 95% CI -8.91 to 39.68). Pre-HD serum zinc levels were significantly lower than those post-HD (mean difference = -7.51 μg/dL, 95% CI -14.24 to -0.78).

CONCLUSION

In the current study, the serum zinc levels were lower in CKD and HD patients compared to HCs and appears to be more common than reported in daily clinical practice. It may be beneficial to assess serum zinc levels in CKD and HD patients. More research on zinc in kidney disease is encouraged.

Serum zinc values, ankle brachial index and mortality in hemodialysis patients

Introduction

The atherosclerotic state of haemodialysis (HD) patients may be influenced by heavy metals. The purpose of our study was to assess the relationship between serum zinc (Zn) ankle brachial index (ABI) as a non-invasive diagnostic tool for atherosclerosis, and mortality in chronic haemodialysis (HD) patients.

Methods

Sixty one HD patients were included (mean age 61.2 ± 13.8 years). The ABI was measured with an automated measuring device (ABPI MD, MESI®, Slovenia). Two groups of patients were formed based on the median value of Zn (14.1 mcmol/l). The average observation time was 2.8 years. Comorbidities (arterial hypertension (AH), diabetes mellitus (DM), dyslipidaemia), smoking and oral nutritional supplements (ONS) consumption were noted. Survival rates were analysed by Kaplan–Meier and Cox regression was used to determine the influence of Zn, ABI, AH, DM, dyslipidaemia, smoking and ONS.

Results

Zn values were between 9.2 and 23.5 mcmol/l (14.4 ± 2.34), ABI values ranged from 0.8 to 1.4 (1.14 ± 0.12). Patients with lower Zn values had lower ABI (p = 0.036). Mean survival time of patients with higher Zn values was 985 days ± 277 days and with lower Zn values 1055 ± 143 days. Six (19.4%) patients with lower Zn and five (16.7%) patients with higher Zn died. We found statistically insignificant lower survival in patients with higher Zn. We failed to find any predictor of all-cause mortality, except for ONS consumption (95% CI 1.6–33.3; p = 0.012).

Conclusions

Lower Zn is associated with lower ABI in HD patients, but we found no impact of Zn on patient survival.

Micronutrients and Renal Outcomes: A Prospective Cohort Study

Background: Micronutrients are essential in maintaining normal human physiology. Data regarding the association between micronutrients and renal outcomes in chronic kidney disease (CKD) are lacking. Methods: This prospective observational cohort study enrolled 261 patients with CKD stages 1−5 and 30 subjects with normal renal function. Baseline serum zinc (Zn), selenium (Se), chromium, manganese, and copper, and laboratory tests were performed at enrolment. The primary endpoint was the presence of end-stage renal disease (ESRD) requiring long-term renal replacement therapy. Results: The median follow-up periods of renal and non-renal survivals were 67.78 and 29.03 months, respectively. Multiple linear regression showed that Zn and Se (β ± SE: 24.298 ± 8.616, p = 0.005; 60.316 ± 21.875, p = 0.006, respectively) levels were positively correlated with renal function. Time to ESRD was significantly longer for those with Zn levels ≥1287.24 ng/g and Se levels ≥189.28 ng/g (both p < 0.001). Cox regression analysis identified a higher Zn level as an independently negative predictor of ESRD after adjusting for renal function (hazard ratio, 0.450, p = 0.019). Conclusion: Serum Se and Zn concentrations are positively associated with renal function and better renal outcomes. A higher Zn concentration could independently predict better renal survival.

Role of Zinc in Diabetic Kidney Disease

Diabetic Kidney Disease (DKD) represents the most common cause of Chronic Kidney Disease (CKD) in developed countries. Approximately 30% to 40% of diabetes mellitus (DM) subjects develop DKD, and its presence significantly increases the risk for morbidity and mortality. In this context, Zinc seems to have a potential role in kidney and body homeostasis in diabetic individuals as well as in patients at a high risk of developing this condition. This essential element has functions that may counteract diabetes-related risk factors and complications, which include stabilization of insulin hexamers and pancreatic insulin storage and improved glycemic control. In our review, we analyzed the current knowledge on the role of zinc in the management of renal impairment in course of DM. Several studies underline the critical role of zinc in reducing oxidative stress levels, which is considered the common denominator of the mechanisms responsible for the progression of kidney disease. Reaching and maintaining a proper serum zinc level could represent a valuable target to reduce symptoms related to DM complications and contrast the progression of kidney impairment in patients with the high risk of developing end-stage renal disease. In conclusion, analyzing the beneficial role of zinc in this review would advance our knowledge on the possible strategies of DM and DKD treatment.

The Role of Zinc in Cardiovascular Disease

Zinc is an essential trace element due to its role as a key part of human enzymatic activity. As a cofactor in metalloenzymes and metalloproteins, zinc participates in diverse biological functions, including gene transcription, translation, and replication, phagocytosis, and immunoglobulin and cytokine production. In this review, we will focus on the role of zinc in the cardiovascular system, including heart failure, vascular calcification, and myocardial infarction. We will further highlight the role of zinc in cardiovascular pathology in individuals with chronic kidney disease, and type II diabetes mellitus, groups uniquely at risk for cardiovascular morbidity and mortality.

Association of Zinc Deficiency with Development of CVD Events in Patients with CKD

Deficiency of the micronutrient zinc is common in patients with chronic kidney disease (CKD). The aim of this review is to summarize evidence presented in literature for consolidation of current knowledge regarding zinc status in CKD patients, including those undergoing hemodialysis. Zinc deficiency is known to be associated with various risk factors for cardiovascular disease (CVD), such as increased blood pressure, dyslipidemia, type 2 diabetes mellitus, inflammation, and oxidative stress. Zinc may protect against phosphate-induced arterial calcification by suppressing activation of nuclear factor kappa light chain enhancer of activated B. Serum zinc levels have been shown to be positively correlated with T₅₀ (shorter T₅₀ indicates higher calcification propensity) in patients with type 2 diabetes mellitus as well as those with CKD. Additionally, higher intake of dietary zinc was associated with a lower risk of severe abdominal aortic calcification. In hemodialysis patients, the beneficial effects of zinc supplementation in relation to serum zinc and oxidative stress levels was demonstrated in a meta-analysis of 15 randomized controlled trials. Thus, evidence presented supports important roles of zinc regarding antioxidative stress and suppression of calcification and indicates that zinc intake/supplementation may help to ameliorate CVD risk factors in CKD patients.

Association between Serum Zinc Levels and Clinical Index or the Body Composition in Incident Hemodialysis Patients

Background: The relationships between serum zinc levels and body composition or clinical outcomes of incident hemodialysis (HD) patients remain unclear. Methods: This prospective observational study examined the relationships between serum zinc levels and clinical indexes, including body composition, in 142 incident HD patients using a bioelectrical impedance analysis. Patients were divided into three groups according to baseline serum zinc levels: tertile, <45, 45–59, and ≥60 µg/dL. The reference group was set as ≥60 µg/dL. Cox’s regression analysis was performed to investigate the relationships between serum zinc categories and cardiovascular events and all-cause mortality after adjustments for potential confounders. Results: Serum zinc levels positively correlated with the nutritional index and negatively correlated with fluid volume markers. In a mean follow-up of 2.5 years, there were 20 cases of cardiovascular events and 15 of all-cause mortality. In the Cox’s regression analysis for cardiovascular events and all-cause mortality, the hazard ratio increased with a decrease in serum zinc levels, but was not significant. Conclusion: Serum zinc levels were associated with nutritional and fluid volume markers in incident HD patients. To clarify the relationship between serum zinc levels and cardiovascular events or mortality, further studies with a larger number of cases will be necessary.

Dietary Patterns and Health Outcomes among African American Maintenance Hemodialysis Patients

The association between dietary patterns and health outcomes, such as quality of life (QOL), in maintenance hemodialysis (MHD) patients with certain racial backgrounds has not been studied in detail. QOL is a powerful outcome measure in which dietary patterns could be a modifying factor. This study is a secondary analysis examining the association between dietary patterns and health outcomes in 101 African American (AA) maintenance hemodialysis (MHD) patients participating in the Palm Tocotrienols in Chronic Hemodialysis (PATCH) study. Quality of life (QOL) was assessed using the Kidney Disease Quality of Life 36-item survey (KDQOL-36™). Blood samples were analyzed for lipids, lipoprotein subfractions, and inflammatory markers. Food intake was measured using six non-consecutive 24-h dietary recalls over 15 months. Implausible energy intake reports were screened out by comparing reported energy intake (rEI) with predicted total energy expenditure (pTEE). Cluster analysis, using the k-means algorithm, identified two distinct dietary patterns in the study population: a high "sugar sweetened beverage" pattern (hiSSB) and a low "sugar sweetened beverage pattern" (loSSB). In the hiSSB group, consumption of SSB accounted for ~28% of energy intake, while SSB represented only 9% of energy intake in the loSSB group. The hiSSB group was characterized by a higher intake of total calories, sugar and percentage of kilocalories from carbohydrates, whereas the percentage of kilocalories from protein and fat was lower. While additional micronutrient intakes differed between groups (vitamin C, zinc, chromium), these were significantly lower than recommended values in the entire cohort. Patients in the hiSSB group presented with lower high-density lipoprotein cholesterol (HDL-C), lower large HDL particles and smaller low density lipoprotein (LDL) particle diameters. Antidepressant usage was significantly higher in the hiSSB group. Patients in the hiSSB group scored lower across all five KDQOL domains and scored significantly lower in the mental composite domain. MHD patients following a hiSSB dietary pattern had smaller dense LDL particles, lower HDL-C, and a lower QOL. Suboptimal intakes of fruits, vegetables, and grains as well as key micronutrients were evident in both patterns.

Potential Role of Nutrient Intake and Malnutrition as Predictors of Uremic Oxidative Toxicity in Patients with End-Stage Renal Disease

Oxidative stress is an important risk factor for cardiovascular disease and death in hemodialysis (HD) patients. However, whether biochemical and nutritional markers might be useful to stratify HD patients according to the risk of oxidative damage remains unclear. We investigated whether low-cost and easily available parameters such as the profile of nutrients intake, nutritional status, and antioxidant defenses can predict lipid and protein oxidation in HD patients. Forty-nine HD patients (women = 20, men = 29), ranging from 18 to 65 years of age (73.5%) were submitted to biochemical and nutritional analysis. At least 93.9% of HD patients had malnutrition. A patient's stratification according to nutritional risk was highly coherent with anthropometric parameters and nutrients intake, which were complementarily used as markers of malnutrition. Nutritional stratification was unable to reveal differences in the oxidative status. On the other hand, carbohydrate and zinc intake, serum zinc (Zn), glutathione peroxidase (GPx) activity, total antioxidant capacity (TAC), and nonprotein antioxidants (npAC) in serum were predictive markers of lipid (R 2 = 0.588, P < 0.001) and protein (R 2 = 0.581, P < 0.001) oxidation. Interestingly, GPx activity, TAC, and npAC exhibited good (>80% < 90%) or excellent (>90%) accuracy to estimate lipid oxidation (P ≤ 0.01). Regarding the prediction of protein oxidation, GPx activity and TAC presented regular accuracy (>70% < 80%), and Zn serum levels exhibited good sensitivity (P ≤ 0.01). Herein, we provided evidence that clinical characteristics relevant to predict different levels of lipid and protein oxidation in HD patients can be easily obtained, during routine hospital visits by means of the combined analyses of biochemical and nutritional parameters.

Effect of Zinc Supplementation on Maintenance Hemodialysis Patients: A Systematic Review and Meta-Analysis of 15 Randomized Controlled Trials

We aimed to examine the effects of zinc supplementation on nutritional status, lipid profile, and antioxidant and anti-inflammatory therapies in maintenance hemodialysis (MHD) patients. We performed a systematic review and meta-analysis of randomized, controlled clinical trials of zinc supplementation. Metaregression analyses were utilized to determine the cause of discrepancy. Begg and Egger tests were performed to assess publication bias. Subgroup analysis was utilized to investigate the effects of zinc supplementation in certain conditions. In the crude pooled results, we found that zinc supplementation resulted in higher serum zinc levels (weighted mean difference [WMD] = 28.489; P < 0.001), higher dietary protein intake (WMD = 8.012; P < 0.001), higher superoxide dismutase levels (WMD = 357.568; P = 0.001), and lower levels of C-reactive protein (WMD = −8.618; P = 0.015) and malondialdehyde (WMD = −1.275; P < 0.001). The results showed no differences in lipid profile. In the metaregression analysis, we found that serum zinc levels correlated positively with intervention time (β = 0.272; P = 0.042) and varied greatly by ethnicity (P = 0.023). Results from Begg and Egger tests showed that there was no significant bias in our meta-analysis (P > 0.1). Results of subgroup analysis supported the above results. Our analysis shows that zinc supplementation may benefit the nutritional status of MHD patients and show a time-effect relationship.

Nutrition and dietary intake and their association with mortality and hospitalisation in adults with chronic kidney disease treated with haemodialysis: protocol for DIET-HD, a prospective multinational cohort study

INTRODUCTION

Adults with end-stage kidney disease (ESKD) treated with haemodialysis experience mortality of between 15% and 20% each year. Effective interventions that improve health outcomes for long-term dialysis patients remain unproven. Novel and testable determinants of health in dialysis are needed. Nutrition and dietary patterns are potential factors influencing health in other health settings that warrant exploration in multinational studies in men and women treated with dialysis. We report the protocol of the "DIETary intake, death and hospitalisation in adults with end-stage kidney disease treated with HaemoDialysis (DIET-HD) study," a multinational prospective cohort study. DIET-HD will describe associations of nutrition and dietary patterns with major health outcomes for adults treated with dialysis in several countries.

METHODS AND ANALYSIS

DIET-HD will recruit approximately 10,000 adults who have ESKD treated by clinics administered by a single dialysis provider in Argentina, France, Germany, Hungary, Italy, Poland, Portugal, Romania, Spain, Sweden and Turkey. Recruitment will take place between March 2014 and June 2015. The study has currently recruited 8000 participants who have completed baseline data. Nutritional intake and dietary patterns will be measured using the Global Allergy and Asthma European Network (GA(2)LEN) food frequency questionnaire. The primary dietary exposures will be n-3 and n-6 polyunsaturated fatty acid consumption. The primary outcome will be cardiovascular mortality and secondary outcomes will be all-cause mortality, infection-related mortality and hospitalisation.

ETHICS AND DISSEMINATION

The study is approved by the relevant Ethics Committees in participating countries. All participants will provide written informed consent and be free to withdraw their data at any time. The findings of the study will be disseminated through peer-reviewed journals, conference presentations and to participants via regular newsletters. We expect that the DIET-HD study will inform large pragmatic trials of nutrition or dietary interventions in the setting of advanced kidney disease.

Increased dialysate MCP-1 is associated with cardiovascular mortality in peritoneal dialysis patients: a prospective observational study

BACKGROUND

The aim of this study was to investigate the association between the dialysate MCP-1 (dMCP-1) and systemic inflammatory and nutritional markers in peritoneal dialysis (PD) patients. In addition, we examined the prognostic value of dMCP-1 on all-cause or cardiovascular mortality in these patients.

METHODS

We prospectively followed 169 prevalent PD patients from April 1st 2008 to December 31st 2012. At baseline, dMCP-1 and serum biochemical parameters including high sensitivity CRP (hs-CRP) and albumin were checked. All-cause mortality and cause of death were evaluated during the follow-up period. Based on the median level of dMCP-1, patients were classified as either low or high dMCP-1 groups.

RESULTS

Mean age, hs-CRP, and D/Pcr ratio at 4 h were significantly higher, while serum albumin levels and %lean body mass (LBM) were significantly lower in the high dMCP-1 group. During the mean follow-up period of 47.7 months, all-cause mortality and cardiovascular mortality rate were significantly higher in the high dMCP-1 group (9.6 and 6.3 per 100 person-years, respectively) compared to the low dMCP-1 group (5.1 and 3.1 per 100 person-years, respectively; p = 0.021, 0.038). In multivariate Cox analysis, high dMCP-1 was a significant independent predictor of all-cause mortality (hazard ratio: 1.83, 95% confidence interval: 1.03-3.24, p = 0.039).

CONCLUSIONS

dMCP-1 levels are closely correlated with nutritional and systemic inflammatory markers in PD patients. In addition, increased dMCP-1 is significantly associated with higher all-cause and cardiovascular mortality. These findings suggest that local peritoneal inflammation could contribute to poor clinical outcomes in PD patients.