Omega-3s and Dialysis: 43% Reduction in Cardiovascular Events
A large randomized clinical trial, the PISCES study, published in the New England Journal of Medicine, demonstrates that four grams of fish oil per day reduces serious cardiovascular events by 43% in hemodialysis patients — a major advance for a population with very limited therapeutic options.
An Exceptionally High Cardiac Risk in Dialysis Patients
Patients undergoing hemodialysis live under the constant threat of a cardiovascular catastrophe. In France, more than 50,000 people depend on kidney dialysis, and cardiovascular diseases account for approximately 50% of deaths — a rate about ten times higher than that of the general population. Yet, effective preventive treatments in this population have remained woefully scarce until now. An international study published in the New England Journal of Medicine could change that.
The PISCES Trial: Rigorous Methodology, Striking Results
The PISCES (Protection against Incidences of Serious Cardiovascular Events Study) clinical trial is a randomized, double-blind, placebo-controlled study conducted in 26 dialysis centers in Canada and Australia. In total, 1,228 adults undergoing maintenance hemodialysis were recruited between 2013 and 2019, then followed for an average of 3.5 years.
The participants were divided into two groups: one received four grams of fish oil daily — equivalent to 1.6 g of eicosapentaenoic acid (EPA) and 0.8 g of docosahexaenoic acid (DHA) — and the other a corn oil-based placebo. The study population was particularly vulnerable: average age of 64 years, 55% with diabetes, 30% with coronary artery disease.
A 43% Reduction in Serious Events
The results, presented at the American Society of Nephrology Kidney Week 2025 and published on November 7, 2025, are remarkable. The rate of serious cardiovascular events — myocardial infarction, stroke, cardiac death, or vascular amputation — was 0.31 events per 1,000 patient-days in the omega-3 group, compared to 0.61 in the placebo group.
This corresponds to a hazard ratio of 0.57 — a relative reduction of 43% (p < 0.001). Broken down by event type, the benefits are consistent: a 63% reduction in stroke risk, a 45% reduction in cardiac death risk, and a 44% reduction in heart attack risk.
« The intervention is simple, inexpensive, widely available, and well-tolerated. This is precisely the type of treatment that nephrology has been waiting for. »
— Commentary published in the New England Journal of Medicine
No Concerning Safety Signals
The tolerability profile of the supplementation proved excellent: no significant difference in adverse effects or adherence between the two groups. Omega-3s at these doses do not cause excessive bleeding or significant metabolic complications in hemodialysis patients.
Major Implications for France and Europe
In France, where nearly 9,500 new patients start dialysis each year, these results directly challenge nephrologists and health authorities. At a modest cost, omega-3 supplementation could be integrated into the management protocols for end-stage chronic kidney disease, provided that a confirmatory trial validates these promising data.
Some experts, however, urge caution. The PISCES trial is a single study, conducted outside of Europe, and the history of preventive cardiology has examples of results that were not replicated. A large-scale confirmatory trial, ideally with European centers, appears essential before establishing widespread recommendations.
Towards a New Standard in Nephrology?
Despite these reservations, the nephro-cardiology community considers the PISCES trial a decisive step. For patients whose preventive options were previously limited to statins and blood pressure control, fish oil represents an accessible, well-tolerated therapeutic avenue, now supported by the highest level of evidence in medicine.
