Risk factors associated with cardiovascular morbidity and mortality in Spanish incident hemodialysis patients: two-year results from the ANSWER study.

AIMS: To identify factors associated with cardiovascular (CV) disease in hemodialysis. METHODS: Multicenter, prospective, 2-year, observational study in 2,310 incident patients (3,496 patient-years). Multivariate Cox models determined baseline characteristics associated with CV disease. RESULTS: Main factors associated with CV deaths (6.3/100 patient-years) were: high Charlson score (hazard ratio (HR) 3.6; 95% confidence interval (CI) 1.7-7.5 for ≥9 vs. ≤4); low Karnofsky score (KS; HR 2.2; 95% CI 1.5-3.3 for KS ≤50 vs. >70); female gender (HR 1.4; 95% CI 1.1-1.9); catheter access (HR 1.4; 95% CI 1.0-1.9); low (<3.5 g/dl) albumin (HR 2.5; 95% CI 1.8-3.3); ferritin deficiency (HR 1.6; 95% CI 1.2-2.2 for <100 vs. ≥100-500 ng/ml) and low body mass index (BMI; HR 1.9; 95% CI 1.2-3.0 for <20 vs. 20-25). A BMI of ≥30 was a protective factor (HR 0.6; 95% CI 0.4-0.9). CONCLUSIONS: There is a high CV risk, especially in older patients with high comorbidity, low BMI, low albumin or iron deficiency. Catheter access increases the CV death risk.

Mortality in incident haemodialysis patients: time-dependent haemoglobin levels and erythropoiesis-stimulating agent dose are independent predictive factors in the ANSWER study.

BACKGROUND: Although the association between low haemoglobin levels and mortality is well established in haemodialysis patients, data are conflicting regarding levels >12 g/dl. In addition, divergent results have been reported on the relation between erythropoiesis-stimulating agents (ESAs) and mortality. METHODS: This was a multicentre, observational, prospective, 24-month study, which recruited Spanish incident haemodialysis patients (N = 2310). Univariate and multivariate time-dependent Cox regression models examined the longitudinal association of mortality with haemoglobin and ESA dose; adjustment was made for iron deficiency and other confounders. RESULTS: After adjusting for age, functional status, body mass index, albumin levels, catheter as vascular access, previous history of cardiovascular disease, neoplasia, and ESA dose, mortality decreased with increasing haemoglobin. Adjusted hazard ratios relative to the reference category (11-12 g/dl) and 95% confidence intervals were: 1.36 (1.01-1.86) for 13 g/dl. Independent of haemoglobin, patients on sustained ESA doses of 1-4000 IU/week and 8001-16 000 IU/week had better survival than non-treated (reference) patients, with adjusted hazard ratios of 0.61 (0.41-0.90) and 0.68 (0.49-0.94), respectively. No significant difference was found for doses of 4001-8000 IU/week or >16,000 IU/week, adjusted hazard ratios of 0.87 (0.63-1.20) and 0.89 (0.63-1.28), respectively. CONCLUSIONS: Higher haemoglobin levels are associated with lower mortality in Spanish incident haemodialysis patients, regardless of ESA dose, comorbidity, vascular access or malnutrition. No increase in mortality occurs for high ESA doses, independent of haemoglobin levels.

Baseline characteristics of an incident haemodialysis population in Spain: results from ANSWER--a multicentre, prospective, observational cohort study.

BACKGROUND: The ANSWER study aims to identify risk factors leading to increased cardiovascular morbidity and mortality in a Spanish incident haemodialysis population. This paper summarizes the baseline characteristics of this population. METHODS: A prospective, observational, one-cohort study, including all consecutive incident haemodialysis patients from 147 Spanish nephrology services, was conducted. Patients were enrolled between October 2003 and September 2004. Sociodemographic, clinical, laboratory and health care characteristics were collected. RESULTS: Baseline characteristics are described for 2341 incident haemodialysis patients [mean (SD) age 65.2 (14.5) years, 63% males]. The main cause of renal failure was diabetic nephropathy (26%). The majority of patients (57%) had a Karnofsky score of 80-100 and 27% were followed up by a nephrologist for 500 ng/ml, 41% and saturated transferrin <20 or >40%, 50%) despite previous treatment with erythropoiesis-stimulating agents in 41% of cases. CONCLUSIONS: There is excessive use of temporary catheters and a high prevalence of uraemia-related cardiovascular risk factors among incident haemodialysis patients in Spain. The poor control of hypertension, anaemia, malnutrition and mineral metabolism and late referral to a nephrologist indicate the need for improving the therapeutic management of patients before the onset of haemodialysis.