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

ABSTRACT: BACKGROUND:Reports on vitamin C in HD patients have shown effects of vitamin C deficiency in association with scurvy symptoms. Dialyzability of water soluble vitamins is high, and substantial losses in those who are dialyzed more frequently were hypothesized. The randomized FHN Daily Trial compared the effects of in-center HD six versus three times per week. We studied baseline correlations between vitamin C and potentially associated parameters, and the effect of more frequent HD on circulating vitamin C concentrations. METHODS:We studied vitamin C levels at baseline and months, 3, 5 and 11. Patients enrolled between 2007 and 2009 into the randomized FHN Daily trial in the East Coast consortium were approached for participation. Predialysis plasma samples were processed with metaphosphoric acid and frozen at -?70?°C for measurement with HPLC. Regression models between baseline log-transformed vitamin C and hemoglobin, CRP, eKt/V, ePCR and PTH, and a linear mixed-effects model to estimate the effect size of more frequent HD on plasma vitamin C, were constructed. RESULTS:We studied 44 subjects enrolled in the FHN Daily trial (50?±?12?years, 36% female, 29% Hispanics and 64% blacks, 60% anuric). Vitamin C correlated significantly with predialysis hemoglobin (r?=?0.3; P?=?0.03) and PTH (r?=?-?0.3, P?=?0.04), respectively. Vitamin C did not significantly differ at baseline (6×/week, 25.8?±?25.9 versus 3×/week, 32.6?±?39.4??mol/L) and no significant treatment effect on plasma vitamin C concentrations was found [-?26.2 (95%CI -57.5 to 5.1) ?mol/L at Month 4 and?-?2.5 (95%CI -15.6 to 10.6) ?mol/L at Month 12. CONCLUSIONS:Based on data from this large randomized-controlled trial no significant effect of the intervention on circulating plasma vitamin C concentrations was found, allaying the concerns that more frequent HD would affect the concentrations of water-soluble vitamins and adversely affect patient's well-being. Correlations between vitamin C and hemoglobin and PTH support the importance of vitamin C for normal bone and mineral metabolism, and anemia management.

SUBMITTER: Raimann JG

PROVIDER: S-EPMC6525383 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

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Project description:BackgroundFew data are available regarding the long-term mortality rate for patients receiving nocturnal home hemodialysis.Study designPosttrial observational study.Setting & participantsFrequent Hemodialysis Network (FHN) Nocturnal Trial participants who consented to extended follow-up.InterventionThe FHN Nocturnal Trial randomly assigned 87 individuals to 6-times-weekly home nocturnal hemodialysis or 3-times-weekly hemodialysis for 1 year. Patients were enrolled starting in March 2006 and follow-up was completed by May 2010. After the 1-year trial concluded, FHN Nocturnal participants were free to modify their hemodialysis prescription.Outcomes & measurementsWe obtained dates of death and kidney transplantation through July 2011 using linkage to the US Renal Data System and queries of study centers. We used log-rank tests and Cox regression to relate mortality to the initial randomization assignment.ResultsMedian follow-up for the trial and posttrial observational period was 3.7 years. In the nocturnal arm, there were 2 deaths during the 12-month trial period and an additional 12 deaths during the extended follow-up. In the conventional arm, the numbers of deaths were 1 and 4, respectively. In the nocturnal dialysis group, the overall mortality HR was 3.88 (95% CI, 1.27-11.79; P=0.01). Using as-treated analysis with a 12-month running treatment average, the HR for mortality was 3.06 (95% CI, 1.11-8.43; P=0.03). Six-month running treatment data analysis showed an HR of 1.12 (95% CI, 0.44-3.22; P=0.7).LimitationsThese results should be interpreted cautiously due to a surprisingly low (0.03 deaths/patient-year) mortality rate for individuals randomly assigned to conventional home hemodialysis, low statistical power for the mortality comparison due to the small sample size, and the high rate of hemodialysis prescription changes.ConclusionsPatients randomly assigned to nocturnal hemodialysis had a higher mortality rate than those randomly assigned to conventional dialysis. The implications of this result require further investigation.

Project description:BackgroundSelf-reported physical health and functioning and direct measures of physical performance are decreased in hemodialysis patients and are associated with mortality and hospitalization.Study designWe determined baseline cross-sectional associations of physical performance, health, and functioning with demographics, clinical characteristics, nutritional indexes, laboratory benchmarks, and measures of body composition in participants in the Frequent Hemodialysis Network (FHN) trial.Setting & participants375 persons enrolled in the FHN with data for physical performance, health, and functioning.PredictorsExplanatory variables were categorized into fixed factors of age, race, comorbid conditions (diabetes mellitus, heart failure, and peripheral arterial disease) and potentially modifiable factors of dialysis dose, phosphorus level, hemoglobin level, equilibrated normalized protein catabolic rate (enPCR), body composition, body mass index, phase angle, and ratio of intracellular water volume to body weight (calculated from bioelectrical impedance).OutcomesScores on tests of physical performance, health, and functioning.MeasurementsPhysical performance measured using the Short Physical Performance Battery, self-reported physical health and functioning using the 36-Item Short Form Health Survey (SF-36). Body composition (body mass index and bioimpedance analysis) and laboratory data were obtained from affiliated dialysis providers.ResultsRelative to population norms, scores for all 3 physicality metrics were low. Poorer scores on all 3 metrics were associated with diabetes mellitus and peripheral arterial disease. Poorer scores on the SF-36 Physical Functioning subscale and Short Physical Performance Battery also were associated with age, lower ratio of intracellular water volume to body weight, and lower enPCR. Black race was associated with poorer scores on the Short Physical Performance Battery.LimitationsThis was a cross-sectional study of individuals agreeing to participate in the FHN study and may not be generalizable to the general dialysis population.ConclusionsHemodialysis patients show markedly impaired physical performance, health, and functioning relative to population norms. Although some factors associated with these impairments are not modifiable, others may change with improvement in nutritional status or body composition.

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

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