Trace elements and vitamins in maintenance dialysis patients

Vitamin Supplement Use in Patients With CKD: Worth the Pill Burden?

All vitamins play essential roles in various aspects of body function and systems. Patients with chronic kidney disease (CKD), including those receiving dialysis, may be at increased risk of developing vitamin deficiencies due to anorexia, poor dietary intake, protein energy wasting, restricted diet, dialysis loss, or inadequate sun exposure for vitamin D. However, clinical manifestations of most vitamin deficiencies are usually subtle or undetected in this population. Testing for circulating levels is not undertaken for most vitamins except folate, B12, and 25-hydroxyvitamin D because assays may not be available or may be costly to perform and do not always correlate with body stores. The last systematic review through 2016 was performed for the Kidney Disease Outcome Quality Initiative (KDOQI) 2020 Nutrition Guideline update, so this article summarizes the more recent evidence. We review the use of vitamins supplementation in the CKD population. To date there have been no randomized trials to support the benefits of any vitamin supplementation for kidney, cardiovascular, or patient-centered outcomes. The decision to supplement water-soluble vitamins should be individualized, taking account the patient's dietary intake, nutritional status, risk of vitamins deficiency/insufficiency, CKD stage, comorbid status, and dialysis loss. Nutritional vitamin D deficiency should be corrected, but the supplementation dose and formulation need to be personalized, taking into consideration the degree of 25-hydroxyvitamin D deficiency, parathyroid hormone levels, CKD stage, and local formulation. Routine supplementation of vitamins A and E is not supported due to potential toxicity. Although more trial data are required to elucidate the roles of vitamin supplementation, all patients with CKD should undergo periodic assessment of dietary intake and aim to receive various vitamins through natural food sources and a healthy eating pattern that includes vitamin-dense foods.

Consenso de expertos sobre la eficacia clínica y directrices sobre la terapia de oxígeno transdérmico continuo para la cicatrización de las heridas complejas o difíciles de cicatrizar

INTRODUCTION

Oxygen is pivotal for wound healing. Its lack or hypoxia can delay this process, especially in individuals with comorbidities, potentially resulting in complex or hard-to-heal wounds. The Colombian Association of Diabetes (ACD) and the Colombian Association of Internal Medicine (ACMI) collaborated with a diverse group of experts to provide recommendations on the efficacy and best practices of continuous transdermal oxygen therapy (TOTc) in the care of such wounds.

METHOD

A modified Delphi technique was employed to obtain controlled feedback and responses. Experts from various disciplines engaged in reviewing and discussing numerous relevant scientific studies, focusing on the role of TOTc in treating chronic ulcers.

RESULTS

Continuous transdermal oxygen therapy has proven to be an effective and safe treatment for chronic and/or hard-to-heal ulcers. This therapy directly addresses the wound's oxygen deficiency, providing an environment conducive to healing. Significant benefits were observed, including the acceleration of the healing process, wound size reduction, and an enhancement in patient quality of life. Its efficacy was found across various ulcer etiologies, underscoring its therapeutic versatility.

CONCLUSIONS

Continuous transdermal oxygen therapy is effective and safe for treating chronic and hard-to-heal ulcers. It's crucial to address each case individually and through a multidisciplinary approach to maximize this therapy's benefits. Both evidence and clinical experience back its utility across a variety of ulcer etiologies.

Nutritional Adequacy of Essential Nutrients in Low Protein Animal-Based and Plant-Based Diets in the United States for Chronic Kidney Disease Patients

OBJECTIVES

The nutritional adequacy of both animal-based and plant-based low protein diets (LPDs) and moderate protein diets that are recommended for patients with chronic kidney disease have not been well examined. We therefore analyzed the nutrient content of three representative LPDs and moderate protein diets (lacto-ovo vegetarian, omnivorous, and vegan) containing foods that are likely to be prescribed for nondialyzed chronic kidney disease or chronic dialysis patients in the United States to determine the nutritional adequacy at different levels of protein intake.

METHODS

Theoretical 3-day menus were developed as per current renal dietary guidelines to model each diet at 7 different levels of protein intake (0.5-1.2 g/kilograms body weight/day [g/kg/d]). The diets were analyzed for their content of essential amino acids (EAAs) and other essential nutrients.

RESULTS

At an a priori recognized inadequate dietary protein level of 0.5 g/kg/d, all 3 diets failed to meet the Recommended Dietary Allowances (RDAs) for the following EAAs: histidine, leucine, lysine, and threonine. The omnivorous LPD met both the RDA and Estimated Average Requirement at levels of 0.6 g protein/kg/d or more. The lacto-ovo and vegan diets at 0.6 and 0.8 g protein/kg/d, respectively, were below the RDA for lysine. The amounts of several other vitamins and minerals were not uncommonly reduced below the RDA or Adequate Intake with all 3 LPDs.

CONCLUSION

In comparison to omnivorous LPDs, both vegan and lacto-ovo LPDs are more likely to be deficient in several EAAs and other essential nutrients. To provide sufficient amounts of all EAA, vegan and lacto-ovo LPDs must be carefully planned to include adequate amounts of appropriate dietary sources. Supplements of some other essential nutrients may be necessary with all three LPDs.

Homocysteine exchange across skeletal muscle in patients with chronic kidney disease

Sites and mechanisms regulating the supply of homocysteine (Hcy) to the circulation are unexplored in humans. We studied the exchange of Hcy across the forearm in CKD patients (n = 17, eGFR 20 ± 2 ml/min), in hemodialysis (HD)-treated patients (n = 14) and controls (n = 9). Arterial Hcy was ~ 2.5 folds increased in CKD and HD patients (p < 0.05-0.03 vs. controls). Both in controls and in patients Hcy levels in the deep forearm vein were consistently greater (+~7%, p < 0.05-0.01) than the corresponding arterial levels, indicating the occurrence of Hcy release from muscle. The release of Hcy from the forearm was similar among groups. In all groups arterial Hcy varied with its release from muscle (p < 0.03-0.02), suggesting that muscle plays an important role on plasma Hcy levels. Forearm Hcy release was inversely related to folate plasma level in all study groups but neither to vitamin B12 and IL-6 levels nor to muscle protein net balance. These data indicate that the release of Hcy from peripheral tissue metabolism plays a major role in influencing its Hcy plasma levels in humans and patients with CKD, and that folate is a major determinant of Hcy release.

Was hat die Ernährung mit der Wundheilung zu tun?

Bei einer Störung im Ablauf der Wundheilung kann es zu einem verzögerten oder fehlenden Wundverschluss kommen. Als ein möglicher Störfaktor gilt die Ernährung. Man muss zwischen quantitativer und qualitativer Mangelernährung unterscheiden. Gerade übergewichtige Patienten leiden oft an einer qualitativen Mangelernährung und Sarkopenie.

Spezifische Erkrankungen machen eine entsprechende diätetische Nahrungsempfehlung notwendig. So findet man bei dialysepflichtigen Patienten, Dekubitus-Patienten und Ulcus cruris-Patienten oft einen Eiweißmangel. Auch niedrige Level an Vitamin C, Zink, Folsäure, Vitamin D oder Spurenelementen können die Wundheilung negativ beeinflussen.

Größere prospektive Studien sollten klären, ob eine Substitution dieser Mangelzustände den gewünschten positiven Effekt auf die Wundheilung hat. Es erscheint aber sinnvoll, eine ausgewogene Ernährung und an die individuellen Ernährungsgewohnheiten angepasste Verbesserung der Aufnahme von Vitaminen, Spurenelementen und Eiweißen anzustreben.

Serum trace metal association with response to erythropoiesis stimulating agents in incident and prevalent hemodialysis patients

Alterations in hemodialysis patients' serum trace metals have been documented. Early studies addressing associations levels of serum trace metals with erythropoietic responses and/or hematocrit generated mixed results. These studies were conducted prior to current approaches for erythropoiesis stimulating agent (ESA) drug dosing guidelines or without consideration of inflammation markers (e.g. hepcidin) important for regulation of iron availability. This study sought to determine if the serum trace metal concentrations of incident or chronic hemodialysis patients associated with the observed ESA response variability and with consideration to ESA dose response, hepcidin, and high sensitivity C-reactive protein levels. Inductively-coupled plasma-mass spectrometry was used to measure 14 serum trace metals in 29 incident and 79 prevalent dialysis patients recruited prospectively. We compared these data to three measures of ESA dose response, sex, and dialysis incidence versus dialysis prevalence. Hemoglobin was negatively associated with ESA dose and cadmium while positively associated with antimony, arsenic and lead. ESA dose was negatively associated with achieved hemoglobin and vanadium while positively associated with arsenic. ESA response was positively associated with arsenic. Vanadium, nickel, cadmium, and tin were increased in prevalent patients. Manganese was increased in incident patients. Vanadium, nickel, and arsenic increased with time on dialysis while manganese decreased. Changes in vanadium and manganese were largest and appeared to have some effect on anemia. Incident and prevalent patients' chromium and antimony levels exceeded established accepted upper limits of normal.

KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for nutrition in kidney diseases since 1999. Since the publication of the first KDOQI nutrition guideline, there has been a great accumulation of new evidence regarding the management of nutritional aspects of kidney disease and sophistication in the guidelines process. The 2020 update to the KDOQI Clinical Practice Guideline for Nutrition in CKD was developed as a joint effort with the Academy of Nutrition and Dietetics (Academy). It provides comprehensive up-to-date information on the understanding and care of patients with chronic kidney disease (CKD), especially in terms of their metabolic and nutritional milieu for the practicing clinician and allied health care workers. The guideline was expanded to include not only patients with end-stage kidney disease or advanced CKD, but also patients with stages 1-5 CKD who are not receiving dialysis and patients with a functional kidney transplant. The updated guideline statements focus on 6 primary areas: nutritional assessment, medical nutrition therapy (MNT), dietary protein and energy intake, nutritional supplementation, micronutrients, and electrolytes. The guidelines primarily cover dietary management rather than all possible nutritional interventions. The evidence data and guideline statements were evaluated using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

The effect of hemodialysis, peritoneal dialysis and renal transplantation on nutritional status and serum micronutrient levels in patients with end-stage renal disease; Multicenter, 6-month period, longitudinal study

PURPOSE

Nutritional status and micronutrient levels of end stage renal disease (ESRD) patients may vary depending on the mode of renal replacement therapy (RRT). We aimed to compare the effects of hemodialysis, peritoneal dialysis (PD) and renal transplantation (RT) on micronutrient levels and nutritional status in ESRD patients.

PATIENTS AND METHODS

A total of 77 ESRD patients who had not received RRT were included in this prospective longitudinal study. All ESRD patients underwent a blood serum analysis that assessed the micronutrients such as selenium, copper, zinc, chromium, retinol, thiamine and vitamin B6 as well as a nutritional status assessment. After the baseline assessments and the initiation of RRT was accomplished, all patients were followed for 6 months.

RESULTS

The study showed significant improvements in subjective global assessment scores (percentage increases in score A were 26.6 and 36.6; p = 0.039 and p = 0.001; respectively), mid-arm circumference and the skin-fold thicknesses (p < 0.001, p < 0.001; respectively) in the RT and hemodialysis groups. The examinations at sixth month revealed a significant increase in body weight (4.8 kg; p = 0.002) and albumin levels (0.6 g/dL; p < 0.001) in only RT group. Zinc, thiamin and vitamin B6 were the most deficient micronutrients (44.1 %, 24.7 % and 35.1 %; respectively) in ESRD patients. There was a significant increase in selenium and retinol levels (p = 0.020 and p < 0.001; respectively) but a significant decrease in thiamin levels (p = 0.041) in RT patients. A significant increase in retinol levels (p = 0.028) and a significant decrease in thiamin levels (p = 0.022) was observed in the hemodialysis patients. However, no significant change in micronutrient levels was observed in the PD patients.

CONCLUSION

The results support the recommendation that ESRD patients should be supplemented with water-soluble vitamins, especially thiamine and vitamin B6, and trace elements, especially zinc. RT appears to be superior to other modes of RRT when examining SGA score, anthropometric measurements, albumin and micronutrient levels.

Actual diet and nutritional deficiencies status in children on peritoneal dialysis at the Vietnam National Hospital of Pediatrics

Nutrition is essential for children with end-stage renal disease, especially for those suffering from peritoneal dialysis (PD). Although the number of PD children has increased annually at the Vietnam National Hospital of Pediatrics, studies about the diet and nutritional deficiencies status of PD children is still limited. The aim of this study was to describe the actual diet and status of nutritional deficiencies of PD patients. This cross-sectional study was conducted on 31 PD children aged 2-15 years old using the 24-h dietary recall and biochemical parameters in blood (albumin, hemoglobin, calcium, sodium, potassium, and chloride). The energy intake was lowest in children over 13-year-old with only 32.9% of dietary reference intakes (DRIs). Carbohydrate intake among 10-15-year-old children was 38.1% of DRIs. Daily consumption of sodium was 65.6% and 33%-35% of DRIs for children under and over three-year-old, respectively. In comparison with DRIs, daily consumption of magnesium, iron, and calcium of over 10-year-old children was lower than that of younger children. In terms of vitamins, B-group vitamins, Vitamin C achieved the recommended levels except Vitamin A (63.0%) and Vitamin D (20.0%). The prevalence of children with serum albumin concentration lower than the normal range was 45.2% and prevalence of anemia was 51.6%. The proportion of children with decreased plasma calcium, sodium, and potassium levels was 83.8%, 77.4%, and 12.9%, respectively. PD children's diet lacks energy, protein, lipid, carbohydrate, as well as micronutrients. The prevalence of nutritional deficiencies is remarkably high in PD children.

Antioxidant Supplementation in Renal Replacement Therapy Patients: Is There Evidence?

The disruption of balance between production of reactive oxygen species and antioxidant systems in favor of the oxidants is termed oxidative stress (OS). To counteract the damaging effects of prooxidant free radicals, all aerobic organisms have antioxidant defense mechanisms that are aimed at neutralizing the circulating oxidants and repair the resulting injuries. Antioxidants are either endogenous (the natural defense mechanisms produced by the human body) or exogenous, found in supplements and foods. OS is present at the early stages of chronic kidney disease, augments progressively with renal function deterioration, and is further exacerbated by renal replacement therapy. End-stage renal disease patients, on hemodialysis (HD) or peritoneal dialysis (PD), suffer from accelerated OS, which has been associated with increased risk for mortality and cardiovascular disease. During HD sessions, the bioincompatibility of dialyzers and dialysate trigger activation of white blood cells and formation of free radicals, while a significant loss of antioxidants is also present. In PD, the bioincompatibility of solutions, including high osmolality, elevated lactate levels, low pH, and accumulation of advanced glycation end-products trigger formation of prooxidants, while there is significant loss of vitamins in the ultrafiltrate. A number of exogenous antioxidants have been suggested to ameliorate OS in dialysis patients. Vitamins B, C, D, and E, coenzyme Q10, L-carnitine, a-lipoic acid, curcumin, green tea, flavonoids, polyphenols, omega-3 polyunsaturated fatty acids, statins, trace elements, and N-acetylcysteine have been studied as exogenous antioxidant supplements in both PD and HD patients.

Determining Serum Zinc and Magnesium Levels in Hemodialysis Patients Could be Helpful for Clinicians

Trace element determination is requested rarely for critically ill patients in Iran, due to the underestimation of the trace element determination by Iranian physicians. The aim was to compare the levels of Zn and Mg in a group of hemodialysis patients and normal individuals. This study shows that trace element determination is helpful for management of hemodialysis patients. Fifty-three hemodialysis patients and 51 control individuals were randomly analyzed for Zn and Mg serum levels. Comparison of before or after dialysis and with normal individuals was done and receiver operating characteristics (ROC) curves were plotted to evaluate the analytical sensitivity and specificity of Zn and Mg determination. Confidence interval for all statistical methods was 95 %. Zinc serum levels were decreased after hemodialysis insignificantly (P = 0.201) but Mg levels were decreased significantly (P = 0.000). Both Zn and Mg levels, before and after hemodialysis were meaningfully lower than normal controls (P < 0.05). ROC analysis showed that the area under the curve was high for Zn levels both before and after hemodialysis but it was high for Mg only before hemodialysis. Current study shows that serum Zn and Mg measurements can have clinical importance. Both before and after hemodialysis, serum Zn = 297.5 µg/L and Mg = 2.295 µg/L are proposed as cut-off values with about 90 % specificity, for monitoring of these two element in hemodialysis patients. It is suggested that clinicians consider the measurement of these trace elements for hemodialysis patients routinely or periodically as clinical chemistry tests.

Development and application of novelty pretreatment method for the concurrent quantitation of eleven water-soluble B vitamins in ultrafiltrates after renal replacement therapy

Continous renal replacement therapy (CRRT) is particularly recommended for septic shock patients in intensive care units. The CRRT technique used most frequently is high volume continuous veno-venous haemofiltration. It provides a high rate of clearance of uremic toxins and inflammatory cytokines. However, it should also be taken into account that substances important for homeostasis may be concurrently unintentionally removed. Accordingly, water-soluble vitamins can be removed during continuous renal replacement therapy, and the estimate of the loss is critical to ensure appropriate supplementation. The aim of this work was to develop a simple methodology for a purification step prior to the LC-MS/MS determination of water-soluble vitamins in ultrafiltrate samples. For this purpose, two types of resin and a mix of resins were used as sorbents for the purification step. Moreover, parameters such as the amount of resin and the extraction time were optimized. The LC-MS/MS method was developed and validated for final determination of 11 vitamins. The results demonstrated the high purification capability of DEAE Sephadex resin with recoveries between 65 and 101% for water-soluble vitamins from ultrafiltrate samples. An optimized method was applied to assess the loss of B-group vitamins in patients after 24h of renal replacement therapy. The loss of vitamins B2, B6 pyridoxamine, B6 pyridoxal, B7, B1, and B5 in ultrafiltrates was similar in all patients. In the native ultrafiltrates, vitamins B6 pyridoxine, B9 and B12 were not detected.

Impact of dialyzer membrane flux on metal clearance in hemodialysis patients

Deficiency of essential trace elements (such as Cu or Zn) and accumulation of potentially toxic trace elements (as Cd or Pb) are both known to have adverse effects in hemodialysis (HD) patients. Up to our knowledge, no studies about the permeability of low and high flux polysulfone membranes on metal ions during hemodialysis are available. Therefore, the aim of the present study was to address this issue. Forty one hemodialysis patients (19 were using high flux polysulfone membrane while the remaining were using low flux one) participated in the study. Blood levels of Cu, Zn, Cd and Pb were determined by graphite furnace atomic absorption spectrometry among HD patients, before and after dialysis session, as well as among matched 40 healthy persons. Blood concentrations of Cu and Zn in the whole hemodialysis group was significantly lower than those of the healthy control group, on the other hand the toxic metals (Cd and Pb) levels were observed to be significantly higher among HD patients compared to the normal persons. Among the hemodialysis group, there were no significant differences between the low and high flux dialyzer groups in terms of pre-dialysis blood levels of Cu, Zn, Cd and Pb. In addition, significantly decreased levels of all metal ions were observed after dialysis sessions using either low or high flux membranes. An exception was Pb which did not show any difference between pre-dialysis and post-dialysis values in the low flux groupIn conclusion Zn and Cu deficiencies should be considered in the treatment of these patients. High flux membranes are more efficient than low flux ones in removing excess Cd and Pb. Therefore, when high flux membranes are used, chelation therapy might not be required for Cd and Pb overload.

MICS, an easily ignored contributor to arterial calcification in CKD patients

In chronic kidney disease (CKD), simultaneous mineral and skeleton changes are prevalent, known as CKD-mineral bone disorder (CKD-MBD). Arterial calcification (AC) is a clinically important complication of CKD-MBD. It can increase arterial stiffness, which leads to severe cardiovascular events. However, current treatments have little effect on regression of AC, as its mechanisms are still unclear. There are multiple risk factors of AC, among which Malnutrition-Inflammation Complex Syndrome (MICS) is a new and crucial one. MICS, a combined syndrome of malnutrition and inflammation, generally begins at the early stage of CKD and becomes obvious in end-stage renal disease (ESRD). It was linked to reverse epidemiology and associated with increased cardiovascular mortality in ESRD patients. Recent data suggest that MICS can trigger CKD-MBD and accelerate the course of AC. In this present review, we summarize the recent understanding about the aggravating effects of MICS on AC and discuss the possible underlying mechanisms. A series of findings indicate that targeting MICS will provide a potential strategy for treating AC in CKD.

Dietary Quality and Adherence to Dietary Recommendations in Patients Undergoing Hemodialysis

BACKGROUND

The multiple dietary restrictions recommended to hemodialysis patients may be difficult to achieve and, at the same time, may result in nutritional deficiencies rendering a poor dietary quality. We here assess the dietary quality and adherence to renal-specific guideline recommendations among hemodialysis patients from a single center in Canary Islands, Spain.

METHODS

Cross-sectional study, including 91 patients undergoing maintenance hemodialysis. Clinical data and 3-day dietary records were collected. We compared patient's reported nutrients intake with guideline recommendations. We also evaluated their alignment with current American Heart Association dietary guidelines for cardiovascular prevention.

RESULTS

Seventy-seven percent and 50% of patients consumed less than the recommended daily energy and protein, respectively. Although half of the patients met the recommendations for dietary fat intake, this was accounted by an excess of saturated fat in 92% of them. Only 22% consumed sufficient fiber. A very small proportion of patients (less than 50%) met the requirements for vitamins and other micronutrients. Insufficient dietary intake was observed in most patients for all vitamins except for cobalamin. Similarly, inadequate dietary intake was observed for many minerals, by both excess (phosphorus, calcium, sodium, and potassium) and defect (magnesium). Most patients met the recommendations for iron and zinc in their diets.

CONCLUSIONS

A large proportion of hemodialysis patients at our center did not meet current renal-specific dietary recommendations. The quality of the diet was considered poor and proatherogenic according to American Heart Association guidelines.

Dietary restrictions in dialysis patients: is there anything left to eat?

A significant number of dietary restrictions are imposed traditionally and uniformly on maintenance dialysis patients, whereas there is very little data to support their benefits. Recent studies indicate that dietary restrictions of phosphorus may lead to worse survival and poorer nutritional status. Restricting dietary potassium may deprive dialysis patients of heart-healthy diets and lead to intake of more atherogenic diets. There is little data about the survival benefits of dietary sodium restriction, and limiting fluid intake may inherently lead to lower protein and calorie consumption, when in fact dialysis patients often need higher protein intake to prevent and correct protein-energy wasting. Restricting dietary carbohydrates in diabetic dialysis patients may not be beneficial in those with burnt-out diabetes. Dietary fat including omega-3 fatty acids may be important caloric sources and should not be restricted. Data to justify other dietary restrictions related to calcium, vitamins, and trace elements are scarce and often contradictory. The restriction of eating during hemodialysis treatment is likely another incorrect practice that may worsen hemodialysis induced hypoglycemia and nutritional derangements. We suggest careful relaxation of most dietary restrictions and adoption of a more balanced and individualized approach, thereby easing some of these overzealous restrictions that have not been proven to offer major advantages to patients and their outcomes and which may in fact worsen patients' quality of life and satisfaction. This manuscript critically reviews the current paradigms and practices of recommended dietary regimens in dialysis patients including those related to dietary protein, carbohydrate, fat, phosphorus, potassium, sodium, and calcium, and discusses the feasibility and implications of adherence to ardent dietary restrictions and future research.

Wound Healing in Patients With Impaired Kidney Function

Renal impairment has long been known to affect wound healing. However, information on differences in the spectrum of wound healing depending on the type of renal insufficiency is limited. Acute kidney injury (AKI) may be observed with different wound types. On one hand, it follows acute traumatic conditions such as crush injury, burns, and post-surgical wounds, and on the other hand, it arises as simultaneous targeting of skin and kidneys by autoimmune-mediated vasculitis. Chronic kidney disease (CKD) and end-stage renal disease (ESRD) often occur in older people, who have limited physical mobility and predisposition for developing pressure-related wounds. The common risk factors for poor wound healing, generally observed in patients with CKD and ESRD, include poorly controlled diabetes mellitus, neuropathy, peripheral vascular disease, chronic venous insufficiency, and aging. ESRD patients have a unique spectrum of wounds related to impaired calcium-phosphorus metabolism, including calciphylaxis, in addition to having the risk factors presented by CKD patients. Overall, there is a wide range of uremic toxins: they may affect local mechanisms of wound healing and also adversely affect the functioning of multiple systems. In the present literature review, we discuss the association between different types of renal impairments and their effects on wound healing and examine this association from different aspects related to the management of wounds in renal impairment patients.

Dietary intake of trace elements, minerals, and vitamins of patients on chronic hemodialysis

PURPOSE

We aimed to estimate dietary intakes of trace elements, minerals, and vitamins in hemodialysis patients (HDP) of three centers in one metropolitan and two urban areas of Italy.

METHODS

Daily dietary intake was assessed using a 3-day diet diary in 128 HDP.

RESULTS

Mean daily intakes of trace elements were as follows: zinc, 7.6 ± 5.4 mg; copper, 14.3 ± 11.8 mg; selenium, 28.3 ± 18.1 μg; and iron, 7.2 ± 4.1 mg (7.8 ± 2.6 mg in women, 6.9 ± 2.4 mg in men). The distribution of patients by daily intakes of trace elements showed most were under the recommended values, with the exception of copper intake, which was much higher. Mean daily intakes of minerals were as follows: magnesium, 174.4 ± 94.3 mg; phosphorus, 842.6 ± 576.8 mg; calcium, 371.8 ± 363.7 mg; potassium, 1,616.2 ± 897.3 mg; and sodium, 1,350 ± 1,281 mg. Mean daily intakes of vitamins were as follows: vitamin A, 486.1 ± 544.6 μg; vitamin B1, 0.86 ± 0.7 mg; vitamin B2, 1.1 ± 0.7 mg; vitamin B3, 13.3 ± 8.1 mg; vitamin C, 47.8 ± 50.3 mg; and vitamin E, 9.5 ± 3.6 mg. The distribution of patients by daily intakes of vitamins showed most were under the recommended values. Daily intakes of trace elements and vitamins were similar among the three centers and did not differ between dialysis and non-dialysis days.

CONCLUSIONS

Many HDP have daily dietary intakes of trace elements and vitamins below the recommended values, whereas the intake of copper is much higher.

The insufficiency intake of dietary micronutrients associated with malnutrition-inflammation score in hemodialysis population

The relations between dietary micronutrient, nutritional status and inflammation in hemodialysis patients are still unclear. A cross-sectional study was performed in hemodialysis population. 75 hemodialysis patients from South China participated in the dietary and nutritional assessment. Clinical and dietary data were collected. Nutritional status was assessed by Malnutrition-Inflammation Score (MIS) in addition to related anthropometric measurements. And according to the MIS score, the whole hemodialysis patients were divided into normal nutrition group and malnutrition group. The results showed that mid arm circumference (MAC) negatively correlated with MIS (r = −0.425; P = 0.002). The area under the ROC curve (AUC) for MAC was 0.737 (0.614–0.859). Comparing with the normal nutritional group, lower dietary selenium (Se), copper (Cu), iodine (I) and manganese (Mn) intake were observed among patients with malnutrition (P<0.05). While no significant differences of diverse vitamins were found. In conclusion, MAC was effective indicator for assessing nutritional and inflammatory status (P<0.05). The reduction of dietary Se, Cu, I and Mn intake level may be alarming markers for malnutrition and inflammatory status in hemodialysis patients.

Low plasma α-tocopherol concentrations and adverse clinical outcomes in diabetic hemodialysis patients

BACKGROUND AND OBJECTIVES

Trials with the antioxidant vitamin E have failed to show benefit in the general population. Considering the different causes of death in ESRD, this study investigated the association between plasma concentrations of α-tocopherol and specific clinical outcomes in diabetic hemodialysis patients.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

In 1046 diabetic hemodialysis patients (participants of the German Diabetes and Dialysis Study), α-tocopherol was measured in plasma by reversed-phase HPLC. By Cox regression analyses, hazard ratios were determined for prespecified end points according to baseline plasma α-tocopherol levels: sudden death (n=134), myocardial infarction (n=172), stroke (n=89), combined cardiovascular events (n=398), fatal infection (n=107), and all-cause mortality (n=508).

RESULTS

Patients had a mean age of 66±8 years, and mean plasma α-tocopherol level was 22.8±9.6 µmol/L. Levels of α-tocopherol were highly correlated to triglycerides (r=0.63, P<0.001). Patients in the lowest α-tocopherol quartile had (in unadjusted analyses) a 79% higher risk of stroke and a 31% higher risk of all-cause mortality compared with patients in the highest quartile. The associations were attenuated after adjustment for confounders (hazard ratiostroke=1.56, 95% confidence interval=0.75-3.25; hazard ratiomortality=1.22, 95% confidence interval=0.89-1.69, respectively). There was no association between α-tocopherol and myocardial infarction, sudden death, or infectious death.

CONCLUSIONS

Plasma α-tocopherol concentrations were not independently associated with cardiovascular outcomes, infectious deaths, or all-cause mortality in diabetic hemodialysis patients. The lack of association can partly be explained by a confounding influence of malnutrition, which should be considered in the planning of trials to reduce cardiovascular risk in dialysis patients.

Effect of short-term intravenous ascorbic acid on reducing ferritin in hemodialysis patients

Resistance to recombinant erythropoietin (rEPO) in hemodialysis patients may be due to inadequate iron recruitment and defect in iron use. In this cross over randomized clinical trial, 30 hemodialysis patients with serum ferritin levels of ≥500 ng/ml, hemoglobin ≤11.0 g/dl, and transferrin saturation (TSAT) of 20% or less were administrated intravenous iron (50-100 mg/wk) and rEPO (120-360 U/kg/wk) for 6 months. Patients were excluded if there was a clear explanation for rEPO hyporesponsiveness. Patients were divided into two groups. Group1 received standard care and 500 mg of intravenous ascorbic acid (IVAA) with each dialysis session in the first week of each month for a total of 3 months. Group 2 received standard care only. After 2 month washout period, groups were crossed over. Each month hemoglobin (Hb) was assessed. Iron, TIBC (transferrin iron binding capacity), TSAT, iPTH (intact parathyroid hormone), liver enzymes, albumin and cholesterol levels were measured every 3 months. After 3 months of intervention, Hb significantly increased from 10.11 to 12.19 g/dl (P <0 0.001; 95% confidence interval [CI] 2.7-1.4) and TSAT increased from 18.9 to 28.1% (P = 0.008; 95% CI 0.09-3), while ferritin and serum iron declined significantly from 1391 to 938 ng/ml (P = 0.001; 95% CI 216-689), 97.2 to 64.6 (P = 0.001; 95% CI 14.8-50.4) in the study group. Change of Hb over time in IVAA group was significant (P < 0.0005). There were significant differences between two groups in change of Hb level over time (P < 0.0005) and treatment effect (P = 0.002). Baseline laboratory tests were similar in the two groups and there was no carry over effect at phase 2. We showed that low amount of IVAA could reduce ferritin level and enhance Hb and TSAT, suggesting improved iron utilization.

Diagnostic pitfalls in spine surgery: masqueraders of surgical spine disease

Disorders of the spine are common in clinical medicine, and spine surgery is being performed with increasing frequency in the US. Although many patients with an established diagnosis of a true surgically treatable lesion are referred to a neurosurgeon, the evaluation of patients with spinal disorders can be complex and fraught with diagnostic pitfalls. While “common conditions are common,” astute clinical acumen and vigilance are necessary to identify lesions that masquerade as surgically treatable spine disease that can lead to erroneous diagnosis and treatment. In this review, the authors discuss musculoskeletal, peripheral nerve, metabolic, infectious, inflammatory, and vascular conditions that mimic the syndromes produced by surgical lesions. It is possible that nonsurgical and surgical conditions coexist at times, complicating treatment plans and natural histories. Awareness of these diagnoses can help reduce diagnostic error, thereby avoiding the morbidity and expense associated with an unnecessary operation.

Dietary micronutrient intake in peritoneal dialysis patients: relationship with nutrition and inflammation status

OBJECTIVE

To compare dietary intake of micronutrients by peritoneal dialysis (PD) patients according to their nutrition and inflammatory statuses.

DESIGN

This cross-sectional study evaluated 73 patients using subjective global assessment, 24-hour dietary recall, and markers of inflammation [C-reactive protein (CRP), tumor necrosis factor α, and interleukin 6].

RESULTS

Half the patients had an inadequate micronutrient intake. Compared with dietary reference intakes, malnourished patients had lower intakes of iron (11 mg) and of vitamins C (45 mg) and B6 (0.8 mg). Malnourished and well-nourished patients both had lower intakes of sodium (366 mg, 524 mg respectively), potassium (1555 mg, 1963 mg), zinc (5 mg, 7 mg), calcium (645 mg, 710 mg), magnesium (161 mg, 172 mg), niacin (8 mg, 9 mg), folic acid (0.14 mg, 0.19 mg), and vitamin A (365 μg, 404 μg). Markers of inflammation were higher in malnourished than in well-nourished subjects. Compared with patients in lower quartiles, patients in the highest CRP quartile had lower intakes (p < 0.05) of sodium (241 mg vs 404 mg), calcium (453 mg vs 702 mg), vitamin B2 (0.88 mg vs 1.20 mg), and particularly vitamin A (207 μg vs 522 μg).

CONCLUSIONS

Among PD patients, half had inadequate dietary intakes of iron, zinc, calcium and vitamins A, B6, C, niacin, and folic acid. Lower micronutrient intakes were associated with malnutrition and inflammation. Patients with inflammation had lower intakes of sodium, calcium, and vitamins A and B2. Micronutrient intake must be investigated in various populations so as to tailor adequate supplementation.

Trace minerals in patients with end-stage renal disease

The kidneys are famously responsible for maintaining external balance of prevalent minerals, such as sodium, chloride, and potassium. The kidney's role in handling trace minerals is more obscure to most nephrologists. Similarly, the impact of kidney failure on trace mineral metabolism is difficult to anticipate. The associated dietary modifications and dialysis create the potential for trace mineral deficiencies and intoxications. Indeed, there are numerous reports of dialysis-associated mishaps causing mineral intoxication, notable for the challenge of assigning causation. Equally challenging has been the recognition of mineral deficiency syndromes, amid what is often a cacophony of multiple comorbidities that vie for the attention of clinicians who care for patients with chronic kidney disease. In this paper, I review a variety of minerals, some of which are required for maintenance of normal human physiology (the U.S. Food and Drug Administration's list of essential minerals), and some that have attracted attention in the care of dialysis patients. For each mineral, I will discuss its role in normal physiology and will review reported deficiency and toxicity states. I will point out the interesting inter-relationships between several of the elements. Finally, I will address the special concerns of aluminum and magnesium as they pertain to the dialysis population.

Euthyroid Sick Syndrome and Nutritional Status are Correlated with Hyposelenemia in Hemodialysis Patients

Background

Maintenance hemodialysis (HD) patients have altered levels of thyroid hormone (TH) in euthyroid sick syndrome, along with low T3 levels and several nutritional metabolic disturbances. Selenium (Se) is an essential trace element for living organisms, which has been shown to play a major role in thyroid hormone levels and the nutritional metabolism. The aims of the present study were to assess the changes in serum levels of selenium and their correlation with disorders of the endocrine and nutritional metabolism in HD patients.

Methods

Fifty-three uremic patients with hemodialysis were evaluated; 30 healthy volunteers served as controls. Baseline serum concentrations of total triiodothyronine (TT3), free triiodothyronine (FT3), total thyroxine (TT4), and free thyroxine (FT4) were determined by radioimmunoassay (RIA). Serum levels of thyroid-stimulating hormone (TSH) and intact parathyroid hormone (iPTH) were measured by a sensitive immunoradiometric assay (IRMA). Serum selenium was analyzed using Hitachi Z- 2000 polarized Zeeman atomic absorption spectrometry. Other metabolic variables were measured in all patients and control subjects. Multiple correlation analysis was performed among variables.

Results

Higher serum triglyceride, LDL-C, ApoB and lower albumin, HDL-C levels were found in subjects with HD. Mean serum selenium concentration was significantly lower in the HD group than in the control group (p<0.01). The levels of serum TT3 and FT3 in HD patients were significantly lower than in healthy control subjects (p<0.01; p<0.05, respectively), but TT4, FT4 and TSH were not different. However, serum iPTH levels were significantly higher in patients than in controls (p<0.01). In the group of HD patients, serum selenium levels were significantly positively correlated with albumin, HDL-C, TT3 and FT3; and negatively correlated with triglyceride (TG), LDL-C, ApoB and iPTH. Both serum TT3 and FT3 levels were significantly positively correlated with HDL-C; and negatively correlated with TG, LDL-C and ApoB.

Conclusions

These data suggest that hyposelenemia in HD patients correlated with euthyroid sick syndrome with low T3 levels, and nutritional status with hyperlipidemia and hypoalbuminemia which might be involved in dysfunction in the endocrine and nutrition metabolism in dialysis patients.

Involvement of oxidative stress in the impairment in biliary secretory function induced by intraperitoneal administration of aluminum to rats

We have shown that aluminum (Al) induces cholestasis associated with multiple alterations in hepatocellular transporters involved in bile secretory function, like Mrp2. This work aims to investigate whether these harmful effects are mediated by the oxidative stress caused by the metal. For this purpose, the capability of the antioxidant agent, vitamin E, to counteract these alterations was studied in male Wistar rats. Aluminum hydroxide (or saline in controls) was administered ip (27 mg/kg body weight, three times a week, for 90 d). Vitamin E (600 mg/kg body weight) was coadministered, sc. Al increased lipid peroxidation (+50%) and decreased hepatic glutation levels (-43%) and the activity of glutation peroxidase (-50%) and catalase (-88%). Vitamin E counteracted these effects total or partially. Both plasma and hepatic Al levels reached at the end of the treatment were significantly reduced by vitamin E (-40% and -44%, respectively; p<0.05). Al increased 4 times the hepatic apoptotic index, and this effect was fully counteracted by vitamin E. Bile flow was decreased in Altreated rats (-37%) and restored to normality by vitamin E. The antioxidant normalized the hepatic handling of the Mrp2 substrates, rose bengal, and dinitrophenyl-S-glutathione, which was causally associated with restoration of Mrp2 expression. Our data indicate that oxidative stress has a crucial role in cholestasis, apoptotic/necrotic hepatocellular damage, and the impairment in liver transport function induced by Al and that vitamin E counteracts these harmful effects not only by preventing free-radical formation but also by favoring Al disposal.

Serum zinc and copper levels in children with chronic renal failure

We evaluated changes in serum zinc (Zn) and copper (Cu) levels in two groups of children with chronic renal failure (CRF)--children with CRF who were on regular hemodialysis (Group 1, n=40) and children with CRF who were on conservative management (Group 2, n=31)--and in one group of healthy children (Group 3, n=30). All of the participants in the study were between 5-18 years old, and the composition of the three groups was almost identical with respect to age and sex. The length of time the children in Group 1 had been on hemodialysis varied between 3 and 52 months (mean: 20.97+/-14.8 months). To evaluate the impact of the duration of dialysis on serum levels of Zn, we further sub-divided Group 1 patients into two subgroups: Subgroup A patients (n=20) had been on hemodialysis therapy for less than 18 months (mean: 8.85+/-4.83 months); Subgroup B patients (n=20) had been on hemodialysis therapy for longer than 18 months (mean: 33.1+/-10.86 months). The PIXE (proton-induced X-ray emission) was used for measuring the trace elements.

RESULTS

The mean serum level of Zn was lower in the Group 1 (hemodialysis group) children than in the children of Group 2 (on conservative management) and group 3 (healthy children) (p<0.001), but the difference was not significant between Groups 2 and 3. No significant differences in serum levels of Cu were found among the three groups. The serum level of Zn was lower in Subgroup B than in Subgroup A (p<0.001). The correlation test showed that there was an inverse linear relation between the length of time the child was on the hemodialysis regimen and serum Zn levels.

CONCLUSION

Chronic hemodialysis may lead to abnormalities in the serum levels of some trace elements in children with CRF that increase in severity with increasing duration of hemodialysis. Deficiencies of these trace elements--zinc in particular--may contribute to various conditions and symptoms in children undergoing chronic hemodialysis.

Effect of Intravenous Ascorbic Acid in Hemodialysis Patients With EPO-Hyporesponsive Anemia and Hyperferritinemia

BACKGROUND

Although erythropoietin (EPO)-hyporesponsive anemia in hemodialysis patients most commonly results from iron deficiency, the contributory role of chronic inflammation and oxidative stress in its pathogenesis is poorly understood. We conducted an open-label prospective study to assess the effect of vitamin C, an antioxidant, on EPO-hyporesponsive anemia in hemodialysis patients with unexplained hyperferritinemia.

METHODS

Forty-six of 262 patients in an inner-city hemodialysis center met the inclusion criteria (administration of intravenous iron and EPO for > or = 6 months at a dose > or = 450 U/kg/wk, average 3-month hemoglobin [Hb] level < or = 11.0 g/dL [< or = 110 g/L], ferritin level > or = 500 ng/mL (microg/L), and transferrin saturation [TSAT] < or = 50%). Patients were excluded if they had a clear explanation for the EPO hyporesponsiveness. Four patients refused to participate. The remaining patients were randomly assigned; 20 patients to receive standard care and 300 mg of intravenous vitamin C with each dialysis session (group 1) and 22 patients to receive standard care only (group 2). Study duration was 6 months. During the study, 1 patient from group 1 was removed (upper gastrointestinal bleeding) from final analysis. Monthly assessment included Hb level, mean corpuscular volume, iron level, iron-binding capacity, ferritin level, TSAT, and Hb content in reticulocytes. In addition, biointact parathyroid hormone, aluminum, C-reactive protein (CRP), and liver enzymes were measured every 3 months.

RESULTS

Age, sex, race, and time on dialysis therapy were similar in both groups. At 6 months, Hb levels significantly increased from 9.3 to 10.5 g/dL (93.0 to 105.0 g/L) in group 1, but not group 2 (9.3 to 9.6 g/dL [93.0 to 96.0 g/L]; P = 0.0001). Similarly, TSAT increased from 28.9% to 37.3% in group 1, but not group 2 (28.7% to 29.3%; P = 0.0001). EPO dose (477 to 429 versus 474 to 447 U/kg/wk), iron-binding capacity (216 to 194 versus 218 to 257 microg/dL [38.7 to 34.7 versus 39 to 46 micromol/L]), and CRP level (2.8 to 0.9 versus 2.8 to 2.2 mg/dL) decreased significantly in group 1, but not in controls. Changes in Hb content in reticulocytes and ferritin level also were statistically significant in group 1. There was no change in biointact parathyroid hormone levels. Although serum iron levels and intravenous iron doses changed within each group, changes were equal between the 2 groups.

CONCLUSION

In hemodialysis patients with refractory anemia and hyperferritinemia, vitamin C improved responsiveness to EPO, either by augmenting iron mobilization from its tissue stores or through antioxidant effects.

Multinutrient Oral Supplements and Tube Feeding in Maintenance Dialysis: A Systematic Review and Meta-Analysis

BACKGROUND

This systematic review aims to determine the potential benefits of enteral multinutrient support (oral or tube) in patients with chronic kidney disease (CKD) receiving maintenance dialysis.

METHODS

Studies of multinutrient oral supplements and enteral tube feeding that involved comparisons of nutritional support versus routine care (ie, usual diet), disease-specific formulae (with adapted macronutrient and micronutrient composition for use in maintenance dialysis patients) versus standard formulae, and enteral tube feeding versus parenteral nutrition are included in this review. The outcome measures sought were clinical (quality of life, complications, and mortality), biochemical (albumin and electrolyte levels), and nutritional (dietary intake and anthropometry). Meta-analyses were performed when possible.

RESULTS

This review of 18 studies (5 randomized controlled trials [RCTs], 13 non-RCTs) suggests that enteral nutritional support increased total (energy and protein) intake and increased serum albumin concentration by 0.23 g/dL (2.3 g/L; 95% confidence interval, 0.037 to 0.418 g/dL [0.37 to 4.18 g/L]; 1 RCT, 2 non-RCTs), with little effect on electrolyte status (serum phosphate and potassium). Few studies reported clinical outcome, and there was insufficient information to compare disease-specific versus standard formulae or enteral versus parenteral nutrition.

CONCLUSION

This systematic review suggests that enteral multinutrient support significantly increases serum albumin concentrations and improves total dietary intake. This may improve clinical outcome, especially in malnourished patients, but insufficient published data exist to examine this. Additional research is required to investigate clinical, economic, and nutritional consequences of using oral supplements and tube feeding (using standard or disease-specific feeds) in patients with CKD receiving maintenance dialysis.