Fish Oil and HDL Function in Patients on Maintenance Hemodialysis (EFFLUX-HD)

August 3, 2026 updated by: Assoc. Prof. Dr. Manfred Hecking, MD PhD, Medical University of Vienna

Mechanistic Effects of n-3 Polyunsaturated Fatty Acid Supplementation on HDL Function in Patients Receiving Maintenance Hemodialysis (EFFLUX-HD): Study Protocol for a Randomized, Open-label, Crossover Trial

Patients who receive maintenance hemodialysis have a very high risk of cardiovascular disease, and standard cholesterol-lowering treatments such as statins have not been shown to reduce cardiovascular events in this group. A recent clinical trial (PISCES) found that high-dose omega-3 fatty acids (fish oil) reduced cardiovascular events in hemodialysis patients, but the reason for this benefit is not understood.

One possible explanation is that, in kidney failure, high-density lipoprotein (HDL) no longer works normally. This study investigates whether omega-3 fatty acid supplementation improves the function of HDL in people on maintenance hemodialysis.

Forty adults on maintenance hemodialysis will take part. Each participant receives fish oil (4 g per day) for 8 weeks and also has an 8-week period without supplementation; participants are randomly assigned to the order of these two periods (crossover design), for a total of 16 weeks each. The main measure is cholesterol efflux capacity, a laboratory test of how well HDL removes cholesterol from cells. The study also examines other markers of HDL quality.

This is an exploratory, mechanistic study. Its aim is to determine whether omega-3 fatty acids change HDL function and to inform the design of larger future trials.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Patients receiving maintenance hemodialysis (HD) experience exceptionally high cardiovascular (CV) mortality that is not adequately addressed by conventional lipid-lowering strategies. The PISCES trial demonstrated that high-dose n-3 polyunsaturated fatty acid (n-3 PUFA) supplementation reduces CV events in HD patients, yet the underlying mechanism remains unknown.

In the uremic milieu, HDL undergoes qualitative changes-including enrichment with serum amyloid A (SAA), loss of anti-oxidative capacity, and impaired cholesterol efflux capacity (CEC)-that render it dysfunctional and may contribute to CV risk independently of HDL cholesterol concentration. Evidence from non-dialysis populations suggests that n-3 PUFA can favorably modify the HDL proteome and improve HDL function. The investigators hypothesize that n-3 PUFA supplementation favorably modulates HDL function in HD patients, which could help explain the CV benefit observed in PISCES.

EFFLUX-HD is a single-center, prospective, randomized, open-label, crossover, exploratory mechanistic study conducted at the Chronic Hemodialysis Unit of the Vienna General Hospital (Medical University of Vienna). Forty adults on maintenance HD are randomized 1:1 to one of two treatment sequences that differ in the order of an 8-week n-3 PUFA supplementation period (4 g/day fish oil; approximately 1.6 g EPA and 0.8 g DHA, matching the PISCES dose) and an 8-week off-treatment period, without a formal washout, for a total of 16 weeks per participant. The crossover design allows each participant to serve as their own control, removing the substantial between-participant variability in HDL functional measures.

Outcomes are analyzed using linear mixed-effects models. No formal sample-size calculation was performed given the exploratory, mechanistic design; the target of 40 participants is intended to estimate within-participant effects and the variability of HDL functional parameters to inform future confirmatory trials. The study was approved by the Ethics Committee of the Medical University of Vienna and is conducted in accordance with the Declaration of Helsinki and the principles of Good Clinical Practice.

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Austria
    • State of Vienna
      • Vienna, State of Vienna, Austria, 1090
        • Chronic Hemodialysis Unit, Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna
        • Contact:
        • Sub-Investigator:
          • Janosch Niknam-Saeidi, MD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • age ≥ 18 years
  • receiving maintenance in-center hemodialysis
  • able to provide written informed consent
  • clinically stable condition (no hospitalization within 4 weeks prior to baseline)

Exclusion Criteria:

  • inability or unwillingness to provide informed consent
  • known hypersensitivity or intolerance to fish oil or n-3 PUFA-containing products
  • use of n-3 PUFA supplements at baseline or within the preceding 8 weeks
  • pregnancy
  • acute infection, hospitalization or major inflammatory condition at the time of baseline assessment
  • any condition that, in the investigator's opinion, would make participation unsafe or interfere with study participation or data interpretation
  • inherited lipid metabolism disorders

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Group A: n-3 PUFA then off-treatment
Participants receive n-3 PUFA supplementation (4 g/day fish oil) for 8 weeks, followed by an 8-week off-treatment period.
Dietary supplement: n-3 PUFA (fish oil)
4g/day fish oil (four 1 g capsules) providing approximately 1.6 g EPA and 0.8 g DHA, taken for 8 weeks, matching the PISCES dose
Experimental: Group B: off-treatment then n-3 PUFA
Participants undergo an 8-week off-treatment period, followed by 8 weeks of n-3 PUFA supplementation (4 g/day fish oil).
Dietary supplement: n-3 PUFA (fish oil)
4g/day fish oil (four 1 g capsules) providing approximately 1.6 g EPA and 0.8 g DHA, taken for 8 weeks, matching the PISCES dose

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Cholesterol Efflux Capacity (CEC)
Time Frame: Weeks 1, 8, and 16
Cholesterol efflux capacity of apolipoprotein B-depleted serum, measured with a cell-based fluorescent assay and reported as percentage cholesterol efflux (%).
Weeks 1, 8, and 16

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Serum Amyloid A (SAA)
Time Frame: Weeks 1, 8, and 16
Serum amyloid A concentration in serum, obtained from routine clinical laboratory measurement and reported in mg/L.
Weeks 1, 8, and 16
Biologically Effective HDL
Time Frame: Weeks 1, 8, and 16
Biologically effective HDL, calculated from concomitantly measured HDL cholesterol and serum amyloid A concentrations and reported in mg/dL.
Weeks 1, 8, and 16

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Medical University of Vienna

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

October 1, 2026

Primary Completion (Estimated)

February 1, 2027

Study Completion (Estimated)

February 1, 2027

Study Registration Dates

First Submitted

July 19, 2026

First Submitted That Met QC Criteria

July 22, 2026

First Posted (Actual)

July 28, 2026

Study Record Updates

Last Update Posted (Actual)

August 4, 2026

Last Update Submitted That Met QC Criteria

August 3, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • EK Nr: 1072/202 (EFFLUX-HD)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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