Effect of vitamin C supplementation on serum uric acid in patients undergoing hemodialysis: a randomized controlled trial.

INTRODUCTION: Clinical studies of recent years have shown that hyperuricemia is associated with poor outcomes such as cardiovascular mortality and dialysis inadequacy in patients undergoing hemodialysis. Our study investigated the effect of vitamin C supplementation on serum uric acid levels in hemodialysis patients. MATERIALS AND METHODS: This randomized placebo-controlled trial was conducted on 172 hemodialysis patients. They were randomly divided into the intervention group, to receive 250 mg of vitamin C, three times per week, for 8 weeks, and control groups 1 and 2, to receive placebo injection (saline) and no intervention, respectively. Serum levels of uric acid and creatinine were measured at the start of the study and also after 8 weeks. RESULTS: The mean of serum levels of uric acid was 6.02 ± 1.08 mg/dL (reference range, 2.6 mg/dL to 6 mg/dL). Nearly, half of the patients (46.7%) had a serum level of uric acid greater than 6 mg/dL. The median baseline serum levels of uric acid were 6.2 mg/dL, 5.9 mg/dL, and 6 mg/dL in the intervention, control 1, and control 2 groups, respectively (P = .19). After 2 months, median levels reduced significantly in the vitamin C group to 5.8 mg/dL as compared to 6.4 mg/dL and 6.3 mg/dL in control groups (P = .02). The mean serum creatinine level had no significant changes during the study. CONCLUSIONS: Our results demonstrated the existence of a significant negative relationship between vitamin C and serum uric acid levels. Detailed investigations with larger sample sizes and longer-term use of vitamin C are recommended.

Effect of Vitamin C Supplementation on C-reactive Protein Levels in Patients Undergoing Hemodialysis: A Randomized, Double Blind, Placebo-Controlled Study.

BACKGROUND: Chronic inflammation is the most important cause of cardiovascular disease in patients undergoing hemodialysis, and vitamin C as a major antioxidant which could be effective to suppress inflammation. OBJECTIVES: This study was performed to evaluate the effect of vitamin C supplementation on C-reactive protein levels in patients undergoing hemodialysis. PATIENTS AND METHODS: This randomized, placebo-controlled and double-blind trial was conducted on 151 patients on hemodialysis who were divided randomly by lottery method to three identical groups. In the intervention group, 250 mg of vitamin C was injected intravenously immediately at the end of each hemodialysis session three times a week for 8 weeks in a row. In the control group 1, same term of placebo saline was injected, and in the control group 2, no intervention was performed. RESULTS: A total of 86 (61%) male and 55 female patients with mean hemodialysis duration of 39.74 ± 45.5 months, and a mean age of 61.36 ± 11.46 years-old, participated in this study. Hypertension and diabetes were the most common underlying diseases (79.4%). Median baseline CRP in the intervention, control 1 and control 2 groups were 16.8, 17.8, and 19.4 mg/L respectively. After 2 months, median CRP reduced significantly in the vitamin C group to 10.7 (P = 0.04) vs. 22.6, and 30.6 mg/L in control groups. CONCLUSIONS: Our findings demonstrated that vitamin C supplementation modifies the levels of CRP in patients on hemodialysis.

Different aspects of fatigue experienced by patients receiving maintenance dialysis in hemodialysis units.

BACKGROUND: Fatigue, a common symptom reported by patients receiving dialysis, is a multidimensional and subjective experience which is readily understood by individuals but difficult to measure. OBJECTIVES: This study was performed to identify the prevalence of differential aspects of fatigue among patients receiving maintenance dialysis. PATIENTS AND METHODS: The cross-sectional study was conducted in two hemodialysis wards in Tehran with a sample of 163 participants. In this study, the multidimensional fatigue inventory was used to determine the level of fatigue. Demographic data were also collected with self-report survey. To analyze data with SPSS statistical software, test Chi square, T-test, and ANOVA were used. P- Value less than 0.05 was considered significant. RESULTS: All the patients experienced degrees of fatigue and 50 (30.7%) of the participants experienced a high level of fatigue. Fatigue scores arrangement was founded for physical fatigue followed by reduced activity and general fatigue. Lower levels of fatigue were reported for mental fatigue and reduced motivation. There was no diversity in this study in the levels of fatigue in respects of gender and marital status and employment status. Participants with diabetic nephropathy were the most fatigued. CONCLUSIONS: People with chronic kidney disease regardless of their age, gender, state of health, and duration of hemodialysis experience high levels of fatigue; it is particularly important for health providers to understand this level of fatigue which affects the daily life of patients.

The effect of vitamin C on parathyroid hormone in patients on hemodialysis with secondary hyperparathyroidism: a double blind, placebo-controlled study.

BACKGROUND: Secondary hyperparathyroidism (SHPT) is a prevalent disorder in patients with chronic kidney disease. It is proffered that there is a contradictory relation between serum level of vitamin C and parathyroid hormone (PTH) in hemodialysis patients with secondary hyperparathyroidism. OBJECTIVES: The goal of this study was to assess the effects of the supplemental vitamin C on parathyroid hormone among hemodialysis patients with secondary hyperparathyroidism. PATIENTS AND METHODS: This randomized, placebo-controlled, double-blind and parallel-group trial was conducted on 82 hemodialysis patients with serum levels of PTH more than 200 pg/mL. In intervention group, 250 mg vitamin C was injected three times a week for 8 weeks in a row immediately at the end of each dialysis session via the intravenous route. In the control group, same term of placebo saline was injected. RESULTS: The mean of serum PTH was 699.81 (± 318.8) and 596.03 (± 410.7) pg/mL in intervention and control groups respectively at baseline (reference range, 6 to 66 pg/mL), and at the end of study it changed to 441.4 and 424.6 in these groups. The values of serum Calcium and Phosphate did not significantly change during the study (8.4 ± 0.6 mg/dL versus 8.1 ± 0.8 mg/dL, P = 0.39; 5.89 ± 1.7 mg/dL versus 5.9 ± 1.9 mg/dL, P = 0.08, respectively). CONCLUSIONS: This study finding does not warranted therapeutic effect of vitamin C on secondary hyperparathyroidism.