Design and patient characteristics of ESHOL study, a Catalonian prospective randomized study.

BACKGROUND: Retrospective studies showed that online hemodiafiltration (OL-HDF) is associated with a risk reduction of mortality over standard hemodialysis (HD) in patients with end-stage renal disease. Until now, no information was available from prospective randomized clinical trials. METHODS: A prospective, randomized, multicenter, open study was designed to be conducted in HD units from Catalonia (Spain). The aim of the study is to compare 3-year survival in prevalent end-stage renal disease patients randomized to OL-HDF or to continue on standard HD. The minimum sample size was calculated according to Catalonian mortality of patients on dialysis and assuming a risk reduction associated with OL-HDF of 35% (1-sided p<0.05 and a statistical power of 0.8) and a rate of dropout due to renal transplantation or loss to follow-up of 30%. RESULTS: From May 2007 to September 2008, 906 patients were included and randomized to OL-HDF (n=456) or standard HD (n=450). Demographics and analytical data at the time of randomization were not different between both groups of patients. Patients will be followed during a 3-year period. CONCLUSION: The present study will contribute to evaluating the benefit for patient survival of OL-HDF over standard HD.

Oxidative stress, inflammation and cardiovascular mortality in haemodialysis--role of seniority and intravenous ferrotherapy: analysis at 4 years of follow-up.

BACKGROUND: Cardiovascular disease is the principal cause of morbidity and mortality in haemodialysis patients. The classic risk factors do not account for all cases of elevated cardiovascular disease in this patient population and it is becoming increasingly clear that other cardiovascular risk factors are implicated. The objective of this study was to analyse whether or not C-reactive protein (CRP) and plasma copper oxidized anti-lipoprotein (oxLDL) antibody titre are risk factors for cardiovascular mortality during 4 years of follow-up. METHODS: A prospective follow-up study was carried out in 94 stable, chronic haemodialysis patients for 48 months (July 1999-July 2003) (gender: 50 males and 44 females; mean age: 67+/-14 years). Eighty-four per cent of these patients were receiving intravenous erythropoietin and 63% were receiving intravenous ferrotherapy (iron gluconate). Basal markers of inflammation and oxidative stress were determined at the beginning of the study. CRP levels were determined by chemiluminescent enzyme-labelled immunometric assay. The oxLDL antibody titre was measured by enzyme-linked immunosorbent assay using native LDL and oxLDL as antigens. RESULTS: Fifty deaths occurred during the study, 66% (n = 33) of which were due to cardiovascular disease. Patients presented with basal CRP and oxLDL levels indicative of chronic inflammation and elevated oxidative stress [CRP median: 5.16 mg/l (25-75% percentile: 0.35-88.7 mg/l); oxLDL antibodies median: 153 (optical density at 495 nm x 1000) (25-75% percentile: 112-214)]. A positive correlation was found between CRP and age (r = 0.33, P = 0.003). Study of the risk factors demonstrated that age (P = 0.007), oxLDL antibody titre (P = 0.04) and albumin (P = 0.02) were the only predictors of cardiovascular mortality at 4 years of follow-up in this patient population. The Cox proportional hazards model for cardiovascular mortality showed that of the markers studied, oxLDL antibody titre was an independent risk factor for cardiovascular mortality. CONCLUSIONS: Oxidative stress (oxLDL antibody titre) is one of the principal risk factors for cardiovascular mortality in this population of haemodialysis patients. Intravenous ferrotherapy, due to its pro-oxidant properties, probably favours oxidative stress. Serum concentration of CRP was not a good predictive factor of cardiovascular mortality during 4 years of follow-up, possibly because of the slight positive correlation that exists between CRP and age.

Homocysteine, C-reactive protein, lipid peroxidation and mortality in haemodialysis patients.

BACKGROUND: Cardiovascular disease (CVD) is common in haemodialysis patients with chronic renal insufficiency and is the leading cause of death. The accelerated state of atherosclerosis found in these patients is due to a combination of different mechanisms. Recent studies confirm that inflammation plays an important role in the development of atherosclerosis. However, the role of hyperhomocysteinaemia and the immune response to oxidation of low-density lipoproteins (LDL) remains unclear and studies show contradictory results. The objective of this study was to determine whether there is a relationship between inflammation, hyperhomocysteinaemia and oxidative stress and whether these CVD risk factors are predictors of mortality in haemodialysis patients. METHODS: A prospective follow-up study was carried out in 94 stable, chronic haemodialysis patients for 24 months (July 1999-July 2001). All the patients were given folic acid and vitamin B complex supplements. Homocysteine was determined by fluorescence polarization immunoassay. C-reactive protein (CRP) levels were determined by chemiluminescent enzyme-labelled immunometric assay. Plasma copper oxidized anti-LDL (oxLDL) antibodies were measured by ELISA using native LDL and oxLDL as antigens. RESULTS: Thirty-two patients died during the study and 59.3% of the deaths could be attributed to CVD (eight to acute myocardial infarction and 11 to non-coronary vascular disease). The patients had slight hyperhomocysteinaemia (25.8 +/- 7.82 micromol/l), evidence of inflammation (CRP 5.16 mg/l (0.35-88.7)) and oxidative stress (oxLDL antibodies = 162 +/- 77 optical density at 495 nm x 1000). Age (P < 0.01), CRP (P = 0.03) and the oxLDL antibody titre (P < 0.01) were predictive of mortality. The patients who died from heart disease showed higher oxLDL antibody titres (P = 0.03). No correlation was found between homocysteine, CRP and the oxLDL antibody titre, or between serum homocysteine levels and the different causes of mortality. CONCLUSIONS: These results suggest that lipid peroxidation and inflammation, but not hyperhomocysteinaemia, are the main risk factors for mortality in haemodialysis patients receiving vitamin supplements. As the study was carried out in a relatively limited number of patients, our findings need to be confirmed in a larger patient population.