Background. While cardiovascular events remain the primary form of mortality in haemodialysis (HD) patients, few centres are aware of the impact of the hydration status (HS). The aim of this study was to investigate how the magnitude of the prevailing overhydration influences long-term survival. Methods. We measured the hydration status in 269 prevalent HD patients (28% diabetics, dialysis vintage = 41.2 ± 70 months) in three European centres with a body composition monitor (BCM) that enables quantitative assessment of hydration status and body composition. The survival of these patients was ascertained after a follow-up period of 3.5 years. The cut off threshold for the definition of hyperhydration was set to 15% relative to the extracellular water (ECW), which represents an excess of ECW of ∼2.5 l. Cox-proportional hazard models were used to compare survival according to the baseline hydration status for a set of demographic data, comorbid conditions and other predictors. Results. The median hydration state (HS) before the HD treatment (� HSpre) for all patients was 8.6 ± 8.9%. The unadjusted gross annual mortality of all patients was 8.5%.

/pdf/the-mortality-risk-of-overhydration-in-haemodialysis-pgvf3ejd50.pdf

The mortality risk of overhydration in haemodialysis patients

Background 
Euvolemia is an important adequacy parameter in peritoneal dialysis (PD) patients. However, accurate tools to evaluate volume status in clinical practice and data on volume status in PD patients as compared to healthy population, and the associated factors, have not been available so far.


Methods 
We used a bio-impedance spectroscopy device, the Body Composition Monitor (BCM) to assess volume status in a cross-sectional cohort of prevalent PD patients in different European countries. The results were compared to an age and gender matched healthy population.


Results 
Only 40% out of 639 patients from 28 centres in 6 countries were normovolemic. Severe fluid overload was present in 25.2%. There was a wide scatter in the relation between blood pressure and volume status. In a multivariate analysis in the subgroup of patients from countries with unrestricted availability of all PD modalities and fluid types, older age, male gender, lower serum albumin, lower BMI, diabetes, higher systolic blood pressure, and use of at least one exchange per day with the highest hypertonic glucose were associated with higher relative tissue hydration. Neither urinary output nor ultrafiltration, PD fluid type or PD modality were retained in the model (total R2 of the model = 0.57).


Conclusions 
The EuroBCM study demonstrates some interesting issues regarding volume status in PD. As in HD patients, hypervolemia is a frequent condition in PD patients and blood pressure can be a misleading clinical tool to evaluate volume status. To monitor fluid balance, not only fluid output but also dietary input should be considered. Close monitoring of volume status, a correct dialysis prescription adapted to the needs of the patient and dietary measures seem to be warranted to avoid hypervolemia.

/pdf/fluid-status-in-peritoneal-dialysis-patients-the-european-12ay44nsec.pdf

Fluid status in peritoneal dialysis patients: the European Body Composition Monitoring (EuroBCM) study cohort.

Background Fluid overload and hypertension are among the most important risk factors for haemodialysis (HD) patients. The aim of this study was to analyse the impact of fluid overload for the survival of HD patients by using a selected reference population from Tassin. Methods A positively selected HD population (n = 50) from Tassin (Lyon-France) was used as a reference for fluid status and all-cause mortality. This population was compared to one dialysis centre from Giessen (Germany) which was separated into a non-hyperhydrated (n = 123) and a hyperhydrated (n = 35) patient group. The hydration status (ΔHS) of all patients was objectively measured with whole-body bioimpedance spectroscopy in 2003. All-cause mortality was analysed after a 6.5-year follow-up. Results Most of the reference patients from Tassin were normohydrated (ΔHS = 0.25 ± 1.15 L) at the start of the HD session. The hydration status of the Tassin patients was not different to the non-hyperhydrated Giessen patients (ΔHS = 0.8 ± 1.1 L) but significantly lower than in the hyperhydrated Giessen group (ΔHS = 3.5 ± 1.2 L). Multivariate adjusted all-cause mortality was significantly increased in the hyperhydrated patient group (hazard ratio = 3.41)- no difference in mortality could be observed between the Tassin and the non-hyperhydrated group from Giessen-even considering the fact that Tassin patients presented a significantly lower blood pressure. Conclusions Fluid overload has a very high predictive value for all-cause mortality and seems to be one of the major killers in the HD population. Patients might strongly benefit from active management of fluid overload.

/pdf/importance-of-normohydration-for-the-long-term-survival-of-zfabwqdl9c.pdf

Importance of normohydration for the long-term survival of haemodialysis patients

https://www.kidney-international.org/article/S0085-2538(15)56222-4/pdf

Volume overload correlates with cardiovascular risk factors in patients with chronic kidney disease

Background. Dry weight assessment (DWA) is essential to efficient therapy of haemodialysis (HD) patients. However, so far objective methods for DWA have not been applicable to daily routine. Thus, exact fluid management in HD remains difficult and is often based on clinical criteria. The aims of this study were (1) to objectively define pre- and post-dialytic ranges of extracellular volume in a large cohort of HD patients (in whom DWA had been defined according to clinical criteria), (2) to compare the hydration status between diabetic and non-diabetic patients, and (3) to assess a patient subgroup that might benefit from correction of target weight. Methods. We measured fluid overload (FO) prior to a mid-week HD session in 370 randomly selected HD patients (50% with diabetes) from five dialysis centres. A new bioimpedance spectroscopy (BIS) device that implies a validated body composition model was applied. This tool allows correct quantification of extracellular FO or − deficiency in comparison to a healthy reference population (normal range −1.1 to 1.1 L according to the 10th and 90th percentile of measurements). In addition, weight and blood pressure were recorded before and after treatment. Results. Pre-dialytic FO ranged from −0.5 to 4 L and postdialytic FO from −2.5 to 2 L (10th and 90th percentile of measurements), indicating that on average the hydration status of healthy subjects is considered as the optimal target weight in HD patients. Comparison of FO between diabetic and non-diabetic patients revealed no difference. Based on the consideration that an FO 1.1 L after HD indicates inadequate DWA, we identified 98 (26%) patients who might benefit from correction of target body weight. Conclusion. BIS is an interesting, objective method to support clinical DWA. Further studies should be performed to investigate beneficial clinical effects of this approach.

/pdf/evaluation-of-clinical-dry-weight-assessment-in-5ascrxb5or.pdf

Evaluation of clinical dry weight assessment in haemodialysis patients using bioimpedance spectroscopy: a cross-sectional study

Protein-energy malnutrition reduces the quality of life, lengthens the time in hospital and dramatically increases mortality. Currently there is no simple and objective method available for assessing nutritional status and identifying malnutrition. The aim of this work is to develop a novel assistance system that supports the physician in the assessment of the nutritional status. Therefore, three subject groups were investigated: the first group consisted of 688 healthy subjects. Two additional groups consisted of 707 patients: 94 patients with primary diseases that are known to cause malnutrition, and 613 patients from a hospital admission screening. In all subjects bioimpedance spectroscopy measurements were performed, and the body composition was calculated. Additionally, in all patients the nutritional status was assessed by the subjective global assessment score. These data are used for the development and validation of the assistance system. The basic idea of the system is that nutritional status is reflected by body composition. Hence, features of the nutritional status, based on the body composition, are determined and compared with reference ranges, derived from healthy subjects' data. The differences are evaluated by a fuzzy logic system or a decision tree in order to identify malnourished patients. The novel assistance system allows the identification of malnourished patients, and it can be applied for screening and monitoring of the nutritional status of hospital patients.

http://iopscience.iop.org/article/10.1088/0967-3334/29/5/009/pdf

M Keymling

Papers

Bioimpedance-based identification of malnutrition using fuzzy logic.