Plasma vitamin C concentrations in patients on routine hemodialysis and its relationship to patients' morbidity and mortality.

BACKGROUND: Some studies have hypothesized the protective role of vitamin C against cardiovascular disorders (CVD) in patients with end-stage renal disease (ESRD). This study was designed to assess plasma vitamin C concentration and its relationship to hemodialysis (HD) patients' morbidity and mortality.
METHODS: Plasma vitamin C concentrations were assessed in HD patients using spectrophotometry and subjects were prospectively followed for up eighteen months for all-cause mortality. Any association between vitamin C concentration and patients' demographic data, co-morbidities, or the cause of ESRD were investigated using the Chi-square test.
RESULTS: Ninety-one patients with a mean age of 56.7 ± 15.7 years were included in this study. The most frequent cause of ESRD was simultaneous hypertension and diabetes in 30 % of patients, followed by hypertension in 25.6 %, and diabetes in 11.1 %, respectively. About 34 % of patients had CVD as the most prevalent co-morbidity. Forty-nine patients (53.8 %) had low levels of vitamin C concentration. There was a significant relationship between vitamin C insufficiency and presence of any co-morbidity in HD patients (p < 0.05). There was a significant difference in vitamin C concentrations between patients without co-morbidities and those with cardiovascular ones (F[2,88]=3.447, p = 0.036). Twenty-two (24.2 %) patients died over a median duration of 227 days. There was a significant difference in time to death of patients with and without low levels of vitamin C concentration (p = 0.04).
CONCLUSIONS: The results showed lower plasma vitamin C levels in HD patients who suffered any co-morbidity and sooner time to death in these patients.