The effect of increased frequency of hemodialysis on vitamin C concentrations: an ancillary study of the randomized Frequent Hemodialysis Network (FHN) daily trial

Assessment and management of vitamin status in children with CKD stages 2-5, on dialysis and post-transplantation: clinical practice points from the Pediatric Renal Nutrition Taskforce

Children with chronic kidney disease (CKD) are at risk for vitamin deficiency or excess. Vitamin status can be affected by diet, supplements, kidney function, medications, and dialysis. Little is known about vitamin requirements in CKD, leading to practice variation.The Pediatric Renal Nutrition Taskforce (PRNT), an international team of pediatric kidney dietitians and pediatric nephrologists, was established to develop evidence-based clinical practice points (CPPs) to address challenges and to serve as a resource for nutritional care. Questions were formulated using PICO (Patient, Intervention, Comparator, Outcomes), and literature searches undertaken to explore clinical practice from assessment to management of vitamin status in children with CKD stages 2-5, on dialysis and post-transplantation (CKD2-5D&T). The CPPs were developed and finalized using a Delphi consensus approach. We present six CPPs for vitamin management for children with CKD2-5D&T. We address assessment, intervention, and monitoring. We recommend avoiding supplementation of vitamin A and suggest water-soluble vitamin supplementation for those on dialysis. In the absence of evidence, a consistent structured approach to vitamin management that considers assessment and monitoring from dietary, physical, and biochemical viewpoints is needed. Careful consideration of the impact of accumulation, losses, comorbidities, and medications needs to be explored for the individual child and vitamin before supplementation can be considered. When supplementing, care needs to be taken not to over-prescribe. Research recommendations are suggested.

Interventions for fatigue in people with kidney failure requiring dialysis

BACKGROUND

Fatigue is a common and debilitating symptom in people receiving dialysis that is associated with an increased risk of death, cardiovascular disease and depression. Fatigue can also impair quality of life (QoL) and the ability to participate in daily activities. Fatigue has been established by patients, caregivers and health professionals as a core outcome for haemodialysis (HD).

OBJECTIVES

We aimed to evaluate the effects of pharmacological and non-pharmacological interventions on fatigue in people with kidney failure receiving dialysis, including HD and peritoneal dialysis (PD), including any setting and frequency of the dialysis treatment.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 18 October 2022 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Studies evaluating pharmacological and non-pharmacological interventions affecting levels of fatigue or fatigue-related outcomes in people receiving dialysis were included. Studies were eligible if fatigue or fatigue-related outcomes were reported as a primary or secondary outcome. Any mode, frequency, prescription, and duration of therapy were considered.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted data and assessed the risk of bias. Treatment estimates were summarised using random effects meta-analysis and expressed as a risk ratio (RR) or mean difference (MD), with a corresponding 95% confidence interval (CI) or standardised MD (SMD) if different scales were used. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Ninety-four studies involving 8191 randomised participants were eligible. Pharmacological and non-pharmacological interventions were compared either to placebo or control, or to another pharmacological or non-pharmacological intervention. In the majority of domains, risks of bias in the included studies were unclear or high. In low certainty evidence, when compared to control, exercise may improve fatigue (4 studies, 217 participants (Iowa Fatigue Scale, Modified Fatigue Impact Scale, Piper Fatigue Scale (PFS), or Haemodialysis-Related Fatigue scale score): SMD -1.18, 95% CI -2.04 to -0.31; I2 = 87%) in HD. In low certainty evidence, when compared to placebo or standard care, aromatherapy may improve fatigue (7 studies, 542 participants (Fatigue Severity Scale (FSS), Rhoten Fatigue Scale (RFS), PFS or Brief Fatigue Inventory score): SMD -1.23, 95% CI -1.96 to -0.50; I2 = 93%) in HD. In low certainty evidence, when compared to no intervention, massage may improve fatigue (7 studies, 657 participants (FSS, RFS, PFS or Visual Analogue Scale (VAS) score): SMD -1.06, 95% CI -1.47, -0.65; I2 = 81%) and increase energy (2 studies, 152 participants (VAS score): MD 4.87, 95% CI 1.69 to 8.06, I2 = 59%) in HD. In low certainty evidence, when compared to placebo or control, acupressure may reduce fatigue (6 studies, 459 participants (PFS score, revised PFS, or Fatigue Index): SMD -0.64, 95% CI -1.03 to -0.25; I2 = 75%) in HD. A wide range of heterogenous interventions and fatigue-related outcomes were reported for exercise, aromatherapy, massage and acupressure, preventing our capability to pool and analyse the data. Due to the paucity of studies, the effects of pharmacological and other non-pharmacological interventions on fatigue or fatigue-related outcomes, including non-physiological neutral amino acid, relaxation with or without music therapy, meditation, exercise with nandrolone, nutritional supplementation, cognitive-behavioural therapy, ESAs, frequent HD sections, home blood pressure monitoring, blood flow rate reduction, serotonin reuptake inhibitor, beta-blockers, anabolic steroids, glucose-enriched dialysate, or light therapy, were very uncertain. The effects of pharmacological and non-pharmacological treatments on death, cardiovascular diseases, vascular access, QoL, depression, anxiety, hypertension or diabetes were sparse. No studies assessed tiredness, exhaustion or asthenia. Adverse events were rarely and inconsistently reported.

AUTHORS' CONCLUSIONS

Exercise, aromatherapy, massage and acupressure may improve fatigue compared to placebo, standard care or no intervention. Pharmacological and other non-pharmacological interventions had uncertain effects on fatigue or fatigue-related outcomes in people receiving dialysis. Future adequately powered, high-quality studies are likely to change the estimated effects of interventions for fatigue and fatigue-related outcomes in people receiving dialysis.

Spontaneous haematomas and haematochezia due to vitamin C deficiency in a haemodialysis patient

A man in his 50s with dialysis-dependent end-stage renal disease, several weeks history of progressive skin bruising and acute-onset gastrointestinal bleeding presented to the emergency department following a syncopal event during routine haemodialysis owing to profound hypotension. He was found to have a severe normocytic, normochromic anaemia requiring several blood transfusions. He followed a diet lacking fruits and vegetables and stopped taking renal multivitamins. All parameters of coagulation were unremarkable, but serum vitamin C level was undetectable, supporting a diagnosis of scurvy. Although typically associated with individuals who are at risk of malnourishment, such as those with alcohol use disorder, malabsorption, and those who experience homelessness, scurvy should be considered in patients receiving renal replacement therapy as vitamin C is removed during haemodialysis.

Reduced Plasma Ascorbate and Increased Proportion of Dehydroascorbic Acid Levels in Patients Undergoing Hemodialysis

Ascorbate functions as an electron donor and scavenges free radicals. Dehydroascorbic acid (DHA), the oxidized form of ascorbate, is generated as a result of these reactions. While low plasma ascorbate levels have been reported in hemodialysis patients worldwide, no studies have measured DHA because it is not generalized. In this study, we aimed to clarify whether plasma ascorbate levels are low in dialysis patients and whether plasma ascorbate levels fluctuate before and after dialysis. Moreover, we applied our previously established method to measure the plasma ascorbate and DHA levels in chronic kidney disease (CKD) stage G3–G5 non-hemodialysis-dependent patients, and pre- and post-dialysis plasma ascorbate and DHA levels in CKD stage G5D hemodialysis patients. The sample size was calculated using G-power software. The pre-dialysis plasma total ascorbate levels, including DHA, were significantly (56%) lower in hemodialysis patients than in non-hemodialysis-dependent CKD patients. After dialysis, there was a 40% reduction in the plasma total ascorbate levels. Hemodialysis increased the post-dialysis plasma proportions of DHA from 37% to 55%. The study results demonstrated lower plasma total ascorbate levels in hemodialysis patients compared with in non-hemodialysis-dependent CKD patients; these low levels in hemodialysis patients were further reduced by hemodialysis and increased DHA proportion.

Two Faces of Vitamin C in Hemodialysis Patients: Relation to Oxidative Stress and Inflammation

Hemodialysis (HD) is the most common method of renal replacement therapy. Besides toxins, it eliminates nutrients from the circulation, such as ascorbic acid (AA). HD-patients present AA deficiency more often than representatives of the general population, also due to dietary restrictions. This condition aggravates oxidative stress and inflammation related to uremia and extracorporeal circulation and increases cardiovascular risk followed by mortality. Supplementation of AA seems to be a promising approach in the treatment of hemodialysis patients. Many successful interventions restored plasma AA concentration in HD patients by enteral or intravenous supplementation, concomitantly inhibiting oxidative stress and inflammation. A significant number of studies reported opposite, serious pro-oxidant effects of AA. In this narrative review, we present studies, commenting on their limitations; on AA plasma or serum concentration and the influence of its supplementation on protein and lipid peroxidation, DNA damage, reactive oxygen species generation, paraoxonase activity, advanced glycation endproducts, and C-reactive protein (CRP) concentration. Moreover, in terms of safety, the possible development of oxalosis in HD patients regarding the intravenous or enteral route of AA administration is discussed. Unequivocal clinical results of recent studies on hemodialysis patients are displayed.

Benefits and risks of frequent or longer haemodialysis: weighing the evidence

Although the ability of individuals with end-stage renal disease to maintain body homoeostasis is equally impaired during all weekdays, conventional haemodialysis (HD) treatment is scheduled thrice weekly, containing two short and one long interdialytic interval. This intermittent nature of HD and the consequent fluctuations in volume, metabolic parameters and electrolytes have long been hypothesized to predispose to complications. Large observational studies link the first weekday with an increased risk of cardiovascular morbidity and mortality. Several schemes of frequent and/or longer, home or in-centre HD have been introduced, aiming to alleviate the above risks by both increasing total dialysis duration and reducing the duration of interdialytic intervals. Observational studies in this field have non-uniform results, showing that enhanced frequency in home (but not in-centre) HD is associated with reduced mortality. Evidence from the randomized Daily and Nocturnal Trials of the Frequent HD Network suggest the opposite, showing mortality benefits with in-centre daily but not with home nocturnal dialysis. Secondary analyses of these trials indicate that daily and nocturnal schedules do not have equal effects on intermediate outcomes. Alternative schemes, such as thrice weekly in-centre nocturnal HD or every-other-day HD, seem to also offer improvements in several intermediate endpoints, but need further testing with randomized trials. This review summarizes the effects of frequent and/or longer HD methods on hard and intermediate outcomes, attempting to provide a balanced overview of the field.