Effects of Hemodiafiltration versus Conventional Hemodialysis in Children with ESKD: The HDF, Heart and Height Study.

BACKGROUND: Hypertension and cardiovascular disease are common in children undergoing dialysis. Studies suggest that hemodiafiltration (HDF) may reduce cardiovascular mortality in adults, but data for children are scarce. METHODS: The HDF, Heart and Height study is a nonrandomized observational study comparing outcomes on conventional hemodialysis (HD) versus postdilution online HDF in children. Primary outcome measures were annualized changes in carotid intima-media thickness (cIMT) SD score and height SD score. RESULTS: We enrolled 190 children from 28 centers; 78 on HD and 55 on HDF completed 1-year follow-up. The groups were comparable for age, dialysis vintage, access type, dialysis frequency, blood flow, and residual renal function. At 1 year, cIMT SD score increased significantly in children on HD but remained static in the HDF cohort. On propensity score analysis, HD was associated with a +0.47 higher annualized cIMT SD score compared with HDF. Height SD score increased in HDF but remained static in HD. Mean arterial pressure SD score increased with HD only. Factors associated with higher cIMT and mean arterial pressure SD-scores were HD group, higher ultrafiltration rate, and higher ß2-microglobulin. The HDF cohort had lower ß2-microglobulin, parathyroid hormone, and high-sensitivity C-reactive protein at 1 year; fewer headaches, dizziness, or cramps; and shorter postdialysis recovery time. CONCLUSIONS: HDF is associated with a lack of progression in vascular measures versus progression with HD, as well as an increase in height not seen in the HD cohort. Patient-related outcomes improved among children on HDF correlating with improved BP control and clearances. Confirmation through randomized trials is required.

Assessing the hydration status of children with chronic kidney disease and on dialysis: a comparison of techniques.

Background: Fluid balance is pivotal in the management of children with chronic kidney disease (CKD) and on dialysis. Although many techniques are available to assess fluid status, there are only a few studies for children, of which none have been comparable against cardiovascular outcome measures. Methods: We performed a longitudinal study in 30 children with CKD5-5D and 13 age-matched healthy controls (71 measurements) to determine a correlation between optimal weight by bioimpedance spectroscopy (Wt-BIS) and clinical assessment (Wt-CA). The accuracy of Wt-BIS [relative overhydration (Rel-OH)] was compared against indicators of fluid status and cardiovascular measures. Results: There was poor agreement between Wt-CA and Wt-BIS in children on dialysis (P = 0.01), but not in CKD5 or control subjects. We developed a modified chart to plot Rel-OH against systolic blood pressure (SBP) z-score for the appropriate representation of volume status and blood pressure (BP) in children. In total, 25% of measurements showed SBP >90th percentile but not with concurrent overhydration. Rel-OH correlated with peripheral pulse pressure (P = 0.03; R = 0.3), higher N-terminal pro-brain natriuretic peptide (P = 0.02; R = 0.33) and left ventricular end-diastolic diameter (P = 0.05; R = 0.38). Central aortic mean and pulse pressure significantly associated with the left ventricular end-diastolic diameter (P = 0.03; R = 0.47 and P = 0.01; R = 0.50, respectively), but not with Rel-OH. SBP was positively associated with pulse wave velocity z-score (P = 0.04). In total, 40% of children on haemodialysis and 30% on peritoneal dialysis had increased left ventricular mass index. Conclusions: BIS provides an objective method for the assessment of hydration status in children on dialysis. We noted a marked discrepancy between BP and hydration status in children on dialysis that warrants further investigation.

Effect of haemodiafiltration vs conventional haemodialysis on growth and cardiovascular outcomes in children - the HDF, heart and height (3H) study.

BACKGROUND: Cardiovascular disease is prevalent in children on dialysis and accounts for almost 30% of all deaths. Randomised trials in adults suggest that haemodiafiltration (HDF) with high convection volumes is associated with reduced cardiovascular mortality compared to high-flux haemodialysis (HD); however paediatric data are scarce. We designed the haemodiafiltration, heart and height (3H) study to test the hypothesis that children on HDF have an improved cardiovascular risk profile, growth and nutritional status and quality of life, compared to those on conventional HD. We performed a non-randomised parallel-arm intervention study within the International Paediatric Haemodialysis Network Registry comparing children on HDF and conventional HD to determine annualised change in cardiovascular end-points and growth. Here we present the 3H study design and baseline characteristics of the study population. METHODS: 190 children were screened and 177 (106 on HD and 71 on HDF) recruited from 28 centres in 10 countries. There was no difference in age, underlying diagnosis, comorbidities, previous dialysis therapy, dialysis vintage, residual renal function, type of vascular access or blood flow between HD and HDF groups. High flux dialysers were used in 63% of HD patients and ultra-pure water was available in 52%. HDF patients achieved a median convection volume of 13.3 L/m2; this was associated with the blood flow rate only ((p = 0.0004, r = 0.42) and independent of access type (p = 0.38). DISCUSSION: This is the largest study on dialysis outcomes in children that involves deep phenotyping across a wide range of cardiovascular, anthropometric, nutritional and health-related quality of life measures, to test the hypothesis that HDF leads to improved cardiovascular and growth outcomes compared to conventional HD. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02063776 . The trial was prospectively registered on the 14 Feb 2014.

Assessing the human carcinogenic potential of tetrahydrofuran: I. Mode of action and human relevance analysis of the male rat kidney tumor.

In 1998, the National Toxicology Program concluded that inhalation exposure to tetrahydrofuran resulted in increased incidences of renal adenomas and carcinomas (combined) in male F344 rats and of hepatocellular adenomas and carcinomas (combined) in female B6C3F1 mice. In the present paper, the bioassay results and additional information are evaluated using the IPCS/ILSI Mode of Action/Human Relevance Framework to determine if the data are sufficient to describe the possible mode(s) of action (MOA) underlying the reported results for the rat renal tumor and to determine if any of these modes of action could be operative in humans. Preliminary analysis of the rat renal tumor data and related information suggested that a MOA could be described, but questions remained concerning the role that chronic progressive nephropathy (CPN) may play in the development of the lesions. In 2009, a Pathology Working Group concluded that the rat renal lesions resulted primarily from regenerative processes associated with advanced CPN. The renal tumor finding is considered not relevant to humans and should not be considered in any further risk assessment efforts on this chemical. A companion paper describes a similar analysis of the female mouse liver tumor finding.

Hemodiafiltration is associated with reduced inflammation, oxidative stress and improved endothelial risk profile compared to high-flux hemodialysis in children.

Randomized trials in adults have shown reduced all-cause and cardiovascular mortality on hemodiafiltration (HDF) compared to high-flux hemodialysis (HD), but the mechanisms leading to improved outcomes are not clear. We studied biomarkers of inflammation, oxidative stress, anti-oxidant capacity and endothelial dysfunction in 22 children (13 female, age 8-15 years). All children received HD for at least 3 months, and were then switched to HDF, keeping all dialysis related parameters and dialysis time constant. All the biomarkers of inflammation (ß2-microglobulin, IL-6, IL-10, high sensitive C-reactive protein [hsCRP]), oxidative stress (nitrotyrosine, advanced glycation end-products [AGEs], oxidized low density lipoprotein [ox-LDL] and anti-oxidant capacity) and endothelial dysfunction (asymmetric dimethyl arginine [ADMA], symmetric dimethyl arginine [SDMA]), were comparable between incident and prevalent patients on HD, suggesting that even a short dialysis vintage of 3 months on HD increases inflammation and endothelial stress. After 3 months of HDF therapy there was a significant reduction in ß2-microglobulin (p<0.001), hCRP, ADMA, SDMA, AGEs, ox-LDL (p<0.01 for all) and an increase in total antioxidant capacity (p<0.001) compared to HD. All children were maintained on the same dialyser, dialysis water quality, dialysis time and blood flow speeds suggesting that improved clearances on HDF led to an improved biomarker profile. Even in children with residual renal function there was a significant reduction in ß2 microglobulin, hsCRP, SDMA, ox-LDL and AGEs on HDF compared to HD. Children with a lower blood flow had higher inflammatory status (higher IL-6/IL-10 ratio; p = 0.04, r = -0.43). Children who achieved a higher convective volume (≥median 12.8L/m2) had lower ox-LDL (p = 0.02). In conclusion, we have shown that a significant improvement in inflammation, antioxidant capacity and endothelial risk profile is achieved even within a short time (3 months) on HDF compared to HD treatment. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02063776.