Impact of targeting Kt instead of Kt/V.

BACKGROUND: Patients must receive an adequate dialysis dose in each hemodialysis (HD) session. Ionic dialysance (ID) enables the dialysis dose to be monitored in each session. The aim of this study was to compare the achievement of Kt versus eKt/V values and to analyse the main impediments to reaching the dialysis dose. METHODS: Of 5316 patients from 54 Fresenius Medical Care centers in Spain undergoing their usual HD regime, 3275 received ID and were included in the study. RESULTS: The minimum prescribed dose of eKt/V was reached in 91.2% of the patients, while the minimum recommended dose of Kt was reached in only 66.8%. Patients not receiving the minimum Kt dose were older, had spent 7 months less on dialysis, had a dialysis duration of 6 min less, had 5.7 kg more of body weight and Qb was 47 mL/min lower. The target Kt was not reached by 62% of patients with catheters and by 37% of women. With each quintile increase of body weight, eKt/V decreased and Kt increased. Of patients with a body weight >80 kg, 1.4%, mostly men, reached the target Kt but not prescribed eKt/V. CONCLUSIONS: The impact of monitoring the dose with Kt instead of Kt/V is that identifies 25.8% of patients who did not reach the minimum Kt while achieving Kt/V. The main impediments to achieving an adequate dialysis dose were catheter use, female sex, advanced age, greater body weight, shorter dialysis time and lower Qb.

Type of vascular access and survival among very elderly hemodialysis patients.

The use of central venous catheters (CVC) for hemodialysis (HD) is associated with higher mortality compared to arteriovenous access (AV). However, studies analyzing the influence of the type of vascular access on the survival of very elderly patients (≥75 years) initiating HD are few and involve only a limited number of patients. We studied a cohort of 5,466 incident patients who started HD; of these, 1,841 were aged ≥75. Types of vascular access for HD were classified as either CVC, which included both tunneled and non-tunneled catheters, or AV, which included AV fistula and grafts. The outcome of the study was all-cause mortality during the follow-up period. In the whole cohort, AV use was associated with a survival advantage over CVC use (88 and 63% at 2 and 5 years, respectively, in patients with an AV as compared to 75 and 48% in patients with a CVC) (p < 0.0001). Among patients ≥75, CVC use was associated with a higher number of deaths compared to AV use. Patients ≥75 with an AV showed a greater survival as compared to patients ≥75 with a CVC (80 and 53% at 2 and 5 years, respectively, vs. 68 and 43%; p < 0.0001). Multivariate analysis revealed that CVC use and the presence of arrhythmia were independent risk factors of death in patients ≥75, whereas obesity was associated with greater survival. In conclusion, the type of vascular access has a significant influence on the survival of very elderly patients (≥75) initiating HD. CVC use was associated with poorer survival compared to AV access.

Hyponatraemia, mortality and haemodialysis: An unexplained association.

BACKGROUND: As in the general population, in patients on haemodialysis (HD) hyponatraemia is associated with higher mortality risk. The objective of this article was to study the relationship between predialysis serum sodium (sNa) and mortality in an HD population. We also intended to define hyponatraemia and determine the characteristics of hyponatraemic patients in terms of anthropometric data, analytical features, dialysis measurements and hydration (bioimpedance). METHODS: Observational, descriptive study of a cohort of HD incident patients. The independent variable was the mean of each patient's sNa analysed during their first 6 months on HD. RESULTS: A total of 4,153 patients were included in the study. Mean age was 64.7 years; 65.2% of the patients were male and 35% were diabetics. Mean follow-up time was 21.48 (SD) (1.31) months. sNa had a normal distribution, with a mean (SD)=138.46 (2.7) mEq/l. Body weight, diabetes mellitus, systolic blood pressure, interdialytic weight gain, total ultrafiltration, serum glucose, albumin and creatinine, vascular access and haemodialysis type, acquire significant differences between sodium quartiles. Lean tissue index (LTI) in patients with low serum sodium, Q1 (135 mEq/l), was significantly lower than the LTI of patients from the other serum sodium quartiles. Patients with sNa<136 mEq/l had a higher independent mortality risk (OR=1.62) (Cox regression analysis). CONCLUSIONS: HD patients with hyponatraemia patients have a poor prognosis and present malnutrition or fluid overload.

Risk identification in haemodialysis patients by appropriate body composition assessment. / Identificar situaciones de riesgo para los pacientes en hemodiálisis mediante la adecuada valoración de su composición corporal.

INTRODUCTION: Circumstances such as gender, age, diabetes mellitus (DM) and renal failure impact on the body composition of patients. However, we use nutritional parameters such as lean and fat tissue with reference values from healthy subjects to assess the nutritional status of haemodialysis (HD) patients. AIMS: To analyse body composition by bioimpedance spectroscopy (BIS) of 6395 HD patients in order to obtain reference values of lean tissue index (LTI) and fat tissue index (FTI) from HD patients; and to confirm its validity by showing that those patients with LTI below the 10th percentile calculated for their group have greatest risk of death. MATERIAL AND METHODS: We used the BIS to determine the LTI and FTI in our cohort of HD patients in Spain. We calculated the 10th percentile and 90th percentile of LTI and FTI in each age decile for patients grouped by gender and presence of DM. We collected clinical, laboratory and demographic parameters. RESULTS: The LTI/FTI 10 and 90 percentile values varied by group (age, gender and presence of DM) and, after adjusting for other risk factors such as fluid overload, those patients with LTI lower than percentile 10 had a higher relative risk of death (OR 1.57) than those patients with higher values. CONCLUSIONS: Monitoring the LTI and FTI of patients on HD using suitable reference values may help to identify risk in this patient population.

Clinical, analytical and bioimpedance characteristics of persistently overhydrated haemodialysis patients.

BACKGROUND: Fluid overload is an important and modifiable cardiovascular risk factor for haemodialysis patients. So far, the diagnosis was based on clinical methods alone. Nowadays, we have new tools to assess more objectively the hydration status of the patients on haemodialysis, as BCM (Body Composition Monitor). A Relative Overhydration (AvROH) higher than 15% (it means, Absolute Overhydration or AWOH higher than 2.5 Litres) is associated to greater risk in haemodialysis. However, there is a group of maintained hyperhydrated patients. The aim of the present study is to identify the characteristics of patients with maintained hyperhydrated status (AvROH higher than 15% or AWOH higher than 2.5 liters). The secondary aim is to show the hemodynamic and analytical changes that are related to the reduction in hyperhydration status. METHODS: Longitudinal cohort study during six months in 2959 patients in haemodialysis (HD) that are grouped according to their hydration status by BCM. And we compare their clinical, analytical and bioimpedance spectroscopy parameters. RESULTS: The change in overhydration status is followed by a decrease in blood pressure and the need for hypotensive drugs (AHT) and erythropoiesis stimulating agents (ESA). The target hydration status is not reached by two subgroups of patients. First, in diabetic patients with a high comorbidity index and high number of hypotensive drugs (AHT) but a great positive sodium gradient during dialysis sessions; and, younger non-diabetic patients with longer time on hemodialysis and positive sodium gradient, lower fat tissue index (FTI) but similar lean tissue index (LTI) and albumin than those with a reduction in hyperhydration status. CONCLUSION: Those patients with a reduction in hyperhydration status, also show a better control in blood pressure and anemia with less number of AHT and ESA. The maintained hyperhydrated patients, diabetic patients with many comorbidities and young men patients with longer time on hemodialysis and non-adherence treatment, can profit from a constant monitoring of their hydration state as well as an individualized treatment (dialysis and drugs).