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

Abstract

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.

Figure 1. Scatter plot of the relation between absolute Δtissue hydration (litres) in the X-axis and systolic blood pressure (mmHg) in the Y-axis in the individual patients of the EuroBCM study cohort.

Dotted vertical lines indicate the 10^th and 90^th percentile of absolute Δtissue hydration in the healthy population (−1.1 and +1.1 liter respectively), representing thus the limits of “normohydration”. Dotted horizontal lines indicate the “normotensive range” for systolic blood pressure.

Figure 2. Box and whisker plots (median, 25^th and 75^th quartile, outliers) of Absolute ΔTissue Hydration (in liters) in the different transport categories.

n.d.: no peritoneal transport characteristics available in the 4 months before the BCM measurement.