Zinc Deficient Intake in Hemodialysis Patients: A Path to a High Mortality Risk

Composite dietary antioxidant index is associated with renal anemia: a cross-sectional study

An increasing evidence suggested that chronic kidney disease (CKD) is closely related to oxidative stress, and dietary antioxidant intake can serve as a primary preventive measure for CKD. However, the relationship between composite dietary antioxidant index (CDAI) and renal anemia is not well understood. We postulated that elevated CDAI levels would be inversely related to a higher likelihood of renal anemia. The standardized calculation of CDAI was performed to investigate the relationship between them by a binary regression model. A non-linear relationship was examined through restricted cubic spline curves, and then pinpointed the inflection point. Subgroup analysis was then used to assess the robustness of the model. Finally 5880 participants were included in the study and a notable correlation between CDAI and renal anemia was found (P < 0.0001). In the multivariate linear regression model with adjustment for all confounding variables, the odds ratio (OR) and 95% confidence interval (CI) was 0.96 (0.94, 0.98; P < 0.0001), A non-linear relationship between CDAI and renal anemia was explored through restricted cubic splines, with a inflection at 6.005. Before the inflection point, for each unit rise in CDAI, the prevalence of renal anemia decreased by 5.7%. Subgroup analysis showed no statistically significant differences in interactions between any subgroups (P > 0.05). Our findings indicated a non-linear negative correlation between CDAI and renal anemia. The causal relationship still needs to be further clarified through large-scale prospective studies.

Water-soluble vitamins and trace elements in children with chronic kidney disease stage 5d

Children receiving maintenance dialysis (chronic kidney disease (CKD) stage 5d) have unique risk factors for micronutrient deficiency or toxicity. Children receiving chronic dialysis often require specialized diet plans that may provide more than the recommended daily allowance (RDA) of water-soluble vitamins and micronutrients, with or without the addition of a kidney-friendly vitamin. The following is a comprehensive review of current literature on disorders of micronutrients in this population including those of water-soluble vitamins (vitamin C and vitamin B complexes) and trace elements (copper, selenium, and zinc) and has three areas of focus: (1) the risk factors and clinical presentations of disorders of micronutrients, both deficiency and toxicity, (2) the tools to evaluate micronutrient status, and (3) the central role of renal dietitians in optimizing nutritional status from a micronutrient perspective.

Associations of Whole Blood Zinc Levels with Coronary Artery Calcification and Future Cardiovascular Events in CKD Patients

This study was conducted to compare the differences of the whole blood zinc concentration in patients with chronic kidney disease (CKD) as compared to healthy controls, and to explore the correlations of the whole blood zinc level with coronary artery calcification (CAC) and cardiovascular event (CVE) in CKD patients. A total of 170 CKD patients and 62 healthy controls were recruited. The whole blood zinc concentration was determined in using atomic absorption spectroscopy (AAS) method. The degrees of CAC were evaluated by Agatston score based on computed tomography (CT). Regular follow-up visits were performed to record the incidence of CVE, and risk factors were analyzed by COX proportional hazard model and Kaplan-Meier survival curve. There were statistically significant lower zinc levels in CKD patients than in healthy population. The prevalence of CAC was 58.82% in CKD patients. Correlation analysis showed that dialysis duration, intact parathyroid hormone (iPTH), alkaline phosphatase (ALP), 25-hydroxyvitamin D3 (25(OH)D3), neutrophil-lymphocyte ratio (NLR), total cholesterol (TC), and high-sensitive C-reactive protein (Hs-CRP) were positively correlated with CAC, while albumin (ALB), hemoglobin (Hb), and zinc levels were negatively associated with CAC. Further COX proportional hazard model demonstrated that moderate to severe CAC, NLR, phosphate, 25(OH)D3, iPTH, and high-density lipoprotein (HDL) were associated with an increased risk for CVE, while zinc levels, Hb, and ALB were inversely associated with a reduced risk for CVE. Kaplan-Meier curve showed that low zinc (zinc < 86.62 μmol/L) patients and moderate to severe CAC patients had lower survival respectively. Our study found the lower levels of zinc and higher prevalence of CAC in CKD patients; the low zinc is involved in the high incidence rate of moderate to severe CAC and CVE in CKD patients.

Recent Advances in the Nutritional Screening, Assessment, and Treatment of Japanese Patients on Hemodialysis

Patients on hemodialysis (HD) have a higher rate of protein-energy wasting (PEW) due to lower dietary intake of energy and protein (particularly on dialysis days) and greater loss of many nutrients in the dialysate effluent than other patients. The most well-known method of nutritional screening is the subjective global assessment. Moreover, the Global Leadership Initiative on MalnutIrition has developed the first internationally standardized method for diagnosing malnutrition; however, its use in patients on HD has not been established. In contrast, the nutritional risk index for Japanese patients on HD has recently been developed as a screening tool for malnutrition in patients on HD, based on the modified PEW criteria. These tools are beneficial for screening nutritional disorders, enabling registered dietitians to assess patients' dietary intake on dialysis and non-dialysis days and provide advice on dietary intake, especially immediately after dialysis cessation. Oral supplementation with enteral nutrients containing whey protein may also be administered when needed. In patients that experience adverse effects from oral supplementation, intradialytic parenteral nutrition (IDPN) should be combined with moderate dietary intake because IDPN alone cannot provide sufficient nutrition.

Comparison of Patient Survival According to Erythropoiesis-Stimulating Agent Type of Treatment in Maintenance Hemodialysis Patients

This study aimed to evaluate the difference in patient survival according to the type of erythropoiesis-stimulating agent (ESA) treatment used in the Korean hemodialysis (HD) population. This retrospective study analyzed the laboratory data from a national HD quality assessment program and the claims of Korea. Included participants were divided into three groups according to the type of ESA used during the 6 months of each assessment period as follows: the EP group (n = 38,043, epoetin-α or epoetin-β), the DP group (n = 10,054, darbepoetin-α), and the MR group (2253, continuous erythropoietin receptor activator). The ESA doses in the EP, DP, and MR groups were 6451 ± 3586, 5959 ± 3857, and 3877 ± 2275 unit/week, respectively. The erythropoiesis resistance indexes (ERIs) in the three groups were 10.7 ± 6.7, 9.9 ± 7.6, and 6.3 ± 4.1 IU/kg/g/dL, respectively. Kaplan−Meier curves revealed similar rates of patient survival among the three groups (p = 0.530). A multivariate Cox regression analysis showed that the hazard ratios in the DP group and MR group were 1.00 (p = 0.853) and 0.87 (p < 0.001), respectively, compared to that of the EP group. The hazard ratio in the MR group was 0.87 (p = 0.001) compared to that of the DP group. Our study shows that the MR group had comparable or better patient survival than the EP and DP groups in the multivariate analysis. However, the ESA doses and ERI were considerably different among the three groups. It was difficult to determine whether the better patient survival in the MR group originated from the ESA type, ESA dose, ERI, or other hidden factors.

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.

Association of Zinc with Anemia

Zinc is an essential trace element, and anemia is the most common blood disorder. The association of zinc with anemia may be divided into three major forms: (1) zinc deficiency contributing to anemia, (2) excess intake of zinc leading to anemia, and (3) anemia leading to abnormal blood-zinc levels in the body. In most cases, zinc deficiency coexists with iron deficiency, especially in pregnant women and preschool-age children. To a lesser extent, zinc deficiency may cooperate with other factors to lead to anemia. It seems that zinc deficiency alone does not result in anemia and that it may need to cooperate with other factors to lead to anemia. Excess intake of zinc is rare. However, excess intake of zinc interferes with the uptake of copper and results in copper deficiency that leads to anemia. Animal model studies indicate that in anemia, zinc is redistributed from plasma and bones to the bone marrow to produce new red blood cells. Inadequate zinc status (zinc deficiency or excess) could have effects on anemia; at the same time, anemia could render abnormal zinc status in the body. In handling anemia, zinc status needs to be observed carefully, and supplementation with zinc may have preventive and curative effects.