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Abstract: SA-PO543

The Impact of Chronic Fluid Overload, Water Imbalance (Tonicity), and Sodium Toxicity on Mortality of Hemodialysis Patients

Session Information

Category: Dialysis

  • 801 Dialysis: Hemodialysis and Frequent Dialysis


  • Pinter, Jule, Julius-Maximilians-Universitat Wurzburg Medizinische Fakultat, Wurzburg, Bayern, Germany
  • Genser, Bernd, Universitat Heidelberg, Heidelberg, Baden-Württemberg, Germany
  • Chesnaye, Nicholas C., Amsterdam Public Health Research Institute, Amsterdam, North Holland, Netherlands
  • Pfeifer, Stefan, Julius-Maximilians-Universitat Wurzburg Medizinische Fakultat, Wurzburg, Bayern, Germany
  • Mayne, Kaitlin J., University of Oxford Nuffield Department of Population Health, Oxford, Oxfordshire, United Kingdom
  • Stuard, Stefano, Fresenius Medical Care Deutschland GmbH, Bad Homburg, Hessen, Germany
  • Moissl, Ulrich, Fresenius Medical Care Deutschland GmbH, Bad Homburg, Hessen, Germany
  • Kooman, Jeroen, Universiteit Maastricht Faculty of Health Medicine and Life Sciences, Maastricht, Limburg, Netherlands
  • Jager, Kitty J., Amsterdam UMC Locatie AMC, Amsterdam, Noord-Holland, Netherlands
  • Wanner, Christoph, Julius-Maximilians-Universitat Wurzburg Medizinische Fakultat, Wurzburg, Bayern, Germany
  • Smyth, Brendan, NHMRC Clinical Trials Centre, Camperdown, New South Wales, Australia
  • Canaud, Bernard J., Universite Montpellier Faculte des Sciences de Montpellier, Montpellier, Occitanie, France

Group or Team Name

  • European Clinical Database5 Study Group.

Chronic fluid overload, water imbalance and plasma sodium toxicity (tonicity) contributes to high mortality in hemodialysis-dependent (HD) patients and the interplay remains unclear. In this retrospective cohort, we aimed to determine the dose-response relationship and interplay between cumulative burden of fluid overload (FO) as measured by body composition (BCM)-measurement, plasma and dialysate sodium on all-cause mortality.


Incident HD-patients with a valid BCM-measurement ≤90 days of renal replacement therapy were eligible. Cumulative exposure was quantified by counting the months spent in exposure status and categorized in deciles or quartiles. Exposure status was defined as FO, hypo and hypernatremia (<135, >145mmol/l) and dialysate sodium ≤138mmol/l. A threshold of 7% defined mild and 13% or 15%, for women and men, severe relative FO. 7% <- normal fluid status was defined as fluid depletion. Hazard Ratios (HR) for defined conditions were estimated from Cox regression frailty model and adjusted for clustering by country and clinics and potential confounding variables.


68,196 incident HD-patients from 875 clinics in 25 countries were followed-up to ten-years (2010-2020), during which 21,644 patients died. The mortality risk associated with FO increased with cumulative exposure burden, mild FO (>1.1 Liter) showed a steeper increase pattern with HR peaking at 3.28 (95%CI: 3.00 to 3.59) than clinically severe FO (>2.5 Liter) (HR peak 2.47(2.33-2.63) compared to normal fluid status (figure 1).


The effect of FO on mortality is large and mandates a sensitive definition to quantify the risk. The dose-response effect of FO is better assessed using the 7% cut-off definition for mild as compared to severe FO. This suggests that the use of a stricter FO definition, could lead to better control of fluid status and improved outcomes.


  • Commercial Support – Fresenius Medical Care