OBJEVTIVE: It has been reported that hyperhomocysteinemia is an independent risk factor for atherosclerotic complications, although the mechanisms remain unclear. The major determinents of total fasting plasma homocysteine(tHcy) concentrations have been recently reported but there are still conflicting data on the influence of those in peritoneal and hemodialysis patients. Therefore, we evaluated the prevalence and association of vascular complications and the determinents of hyperhomocysteinemia in chronic renal failure patients receiving conservative treatment(predialysis), peritoneal dialysis(PD) and hemodia- lysis (HD) patients. METHODS: We measured the factors, including fasting plasma vitamine levels(folate, vitamin B6 and vitamin B12), serum creatinine concentration, dialysis adequacy-related varibles as well as associated risk factors for vascular diseases that might affect tHcy concentrations in 37 predilysis, 30 PD, 34 HD patients and 21 normal persons. Continuous variables were compared using independent sample t-test. Spearman's correlation was used to determine the strength of association between tHcy and other predictive variables. Percentages were compared using Pearson's chi-square test or Fisher's exact test, depending on the frequencies. Independent determinents of tHcy concentration and atherosclerotic vascular complications were identified using multiple regression analysis. RESULTS: The prevalence of hyperhomocysteinemia was 83.8, 72, 88% among predialysis, PD and HD patients,respectively(Odds ratio was 103.33, 81.43, 150.0 vs. controls, respectively). tHcy values in predialysis, PD and HD patients are significantly higher than those in controls(24.68+/-9.01, 21.04+/-8.82, 23.62+/-9.46 vs. 8.80+/-2.07 mumoL/L, repectively, p<0.01). Predialysis, PD and HD patients with atherosclerotic vascular complications had higher tHcy concentrations than did predialysis, PD and HD patients without vascular complications(21.93+/-8.71 vs. 32.09+/-4.71 mumoL/L, p<0.01, 17.57+/-5.85 vs. 28.74+/-9.70 mumoL/L, p<0.01, 19.00+/-4.29 vs. 33.28+/-10.13, p<0.01 respectively). We also observed increasing odds ratios of vascular events with increasing tHcy concentrations. For predialysis, PD and HD patients, fasting plasma folate level had negative correlation with tHcy concentrations by spearman's simple correlaltion. And using muliple regression analysis, we recognized hyperhomocysteinemia is an independent risk factor for atherosclerosis and fasting plasma folate is a major determinent of tHcy concentrations in predialysis, PD and HD patients. CONCLUSIONS: Hyperhomocysteinemia in predialysis, PD and HD patients was more prevalent than that in normal controls. Risk of atherosclerotic vascular complications increased with increasing tHcy concentrations. Hyperhomocysteinemia is an independent risk factor for atherosclerosis and fasting plasma folate is a major determinent of tHcy concentrations in predialysis, PD and HD patients.