Abstract :
Dear Editor, I read with interest the recent contribution by Biniaz and colleagues, which reported the existence of a significant relationship between vitamin C supplementation and serum uric acid (SUA) levels in hemodialysis patients and found that SUA levels were higher in half of these patients. Hyperuricemia is associated with hypertension and chronic kidney disease. Large epidemiological studies have shown that hyperuricemia is associated with an increased incidence of coronary artery disease and increased mortality in those with and without preexisting coronary artery disease. Hemodialysis patients are exposed to oxidative stress which contributes to cardiovascular disease. A study performed in our center demonstrated that plasma malondialdehyde levels were significantly higher and serum paraoxonase activity, SUA, and albumin levels were significantly lower in hemodialysis patients with cardiovascular disease compared to those of the patients without cardiovascular disease. However, the Dialysis Outcomes and Practice Patterns Study revealed that higher SUA levels were associated with lower risk of all-cause and cardiovascular mortality in the hemodialysis population in contrast to the association of hyperuricemia with higher cardiovascular risk in the general population. In a recent study, we found that median vitamin C and SUA levels of 34 maintenance dialysis patients who were not given vitamin C treatment were 0.25 mg/dL (range, 0.17 mg/dL to 2.17 mg/dL) and 7.05 mg/dL (range, 4.7 mg/dL to 9.6 mg/dL), respectively, and there was no significant correlation between vitamin C and SUA levels (r = -0.042, P .05).
