Kidney Week

Abstract: FR-PO0471

Convective Volume, Patient Anthropometric Characteristics, and Risk of All-Cause Mortality in Hemodiafiltration: A Cohort Study

Session Information

• Dialysis: Hemodiafiltration, Ultrafiltration, Profiling, and Interdialytic Symptoms
  November 07, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Dialysis

• 801 Dialysis: Hemodialysis and Frequent Dialysis

Authors

• Cromm, Krister, Fresenius Medical Care Deutschland GmbH, Bad Homburg, HE, Germany

Krister Cromm, MA, MS, MSc, MBA

• Vernooij, Robin W.m., Universitair Medisch Centrum Utrecht, Utrecht, UT, Netherlands

Robin W.m. Vernooij, MS, MSc, PhD

• Canaud, Bernard J., Universite de Montpellier, Montpellier, Occitanie, France

Bernard J. Canaud, MD, PhD

• Barth, Claudia Maria, B Braun Avitum AG, Melsungen, HE, Germany

Claudia Maria Barth, MD

• Hegbrant, Jorgen BA, Lunds Universitet, Lund, Skåne County, Sweden

Jorgen BA Hegbrant, MD, PhD

• Davenport, Andrew, University College London, London, England, United Kingdom

Andrew Davenport, MD

• Woodward, Mark, The George Institute for Global Health UK, Oxford, England, United Kingdom

Mark Woodward, PhD

• Bots, Michiel, Universitair Medisch Centrum Utrecht, Utrecht, UT, Netherlands

Michiel Bots, MD, PhD

• Blankestijn, Peter J., Universitair Medisch Centrum Utrecht, Utrecht, UT, Netherlands

Peter J. Blankestijn, MD, FASN

• Strippoli, Giovanni, Universita degli Studi di Bari Aldo Moro, Bari, Apulia, Italy

Giovanni Strippoli, MD, PhD, MBA

Group or Team Name

• CONVINCE Scientific Committee and Investigators.

Background

Higher ultrafiltration volumes in hemodiafiltration (HDF), a surrogate for convective dose, have been associated with improved survival. Whether this advantage is affected by patients' anthropometric characteristics (body mass index (BMI) or body surface area (BSA)) is unclear.

Methods

We analyzed individual patient data from 5 randomized trials to evaluate the association between convective volume and risk of all-cause mortality stratified by BMI and BSA. Cox proportional hazards models with interaction terms, Kaplan-Meier survival curves and multivariable spline models were used to explore potential nonlinear and joint effects.

Results

Our cohort consisted of 2083 patients treated with HDF. Convective volume, BMI, and BSA were each categorized into tertiles (for volumes: 17.9 L (low), 22.8 L (medium), and 27.7 L (high); for BMI 20.9 kg/m² (low), 25.2 kg/m² (medium), and 31.7 kg/m² (high); for BSA 1.57 m² (low), 1.79 m² (medium), and 2.03 m² (high)). Higher convective volume was significantly associated with reduced all-cause mortality (HR 0.62, 95% CI: 0.49–0.78 for highest vs lowest tertile). In joint analyses, patients with medium or high BMI or BSA receiving high convective volume had the lowest mortality risks (HR: 0.53, 95% CI: 0.36–0.78). In contrast, the interaction between BSA and convection volume was less consistent and did not show a clear gradient (Table).

Conclusion

In patients receiving HDF, high ultrafiltration volumes were associated with significantly lower risk of all-cause mortality, particularly among those with medium to high BMI. This relationship was not consistently observed with BSA. It is plausible that BMI and BSA capture different physiological characteristics. BMI may reflect nutritional status or body composition, while BSA may be a proxy for uremic solute distribution volume. Ultrafiltration volume requirements may align more closely with BMI than BSA, indicating that BMI could be a more practical metric for personalizing convective volume in HDF to optimize patient outcomes.

Funding

• Government Support – Non-U.S.

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.2025htjm85by