Presenter: Charmaine E. Lok, MD, University of Toronto, Ontario, Canada
Protection Against Incidences of Serious Cardiovascular Events Study with daily fish oil supplementation in patients on dialysis (PISCES). Abstract FR-OR082. Presented November 9, 2025.
Among patients on maintenance hemodialysis, omega-3 fatty acid supplementation resulted in a significant reduction in serious cardiovascular events, according to results of a randomized, placebo-controlled trial presented at American Society of Nephrology Kidney Week 2025.
Compared with placebo, daily supplementation with omega-3 polyunsaturated fatty acids was associated with a 43% relative reduction in the risk of serious cardiovascular events in the PISCES study, which was published concurrently in the New England Journal of Medicine.
“For now, PISCES fills the important medical gap for prevention of cardiovascular events in patients treated with maintenance hemodialysis,” said researcher Charmaine E. Lok, MD, University of Toronto, Ontario, Canada.
“Other, interventions, such as certain dialytic modalities, may reduce mortality; however, they may not be available in all areas,” Dr. Lok said in an interview.
There are few effective preventive therapies for cardiovascular disease, the leading cause of death for patients on hemodialysis, according to Dr. Lok and co-authors.
Some research suggests that, in the general population, omega-3 polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) may reduce cardiovascular risks. However, their efficacy among patients receiving hemodialysis is uncertain.
In the PISCES trial, conducted at 26 sites in Canada and Australia, 1,228 adult patients on maintenance hemodialysis were randomized to take daily supplements of fish oil (EPA 1.6 g plus DHA 0.8 g) or a corn-oil placebo.
The primary endpoint was the composite rate of all serious cardiovascular events, including myocardial infarction, stroke, peripheral vascular disease leading to amputation, and cardiovascular death.
Over 3.5 years of follow-up, the rate of serious cardiovascular events in the fish-oil group was 0.31 per 1,000 patient days, versus 0.61 per 1,000 patients days in the placebo group, with a hazard ratio of 0.57 (P < .001), the reported data show.
The benefits were seen for each individual component of that composite endpoint, the investigators said, including cardiac death, fatal and nonfatal myocardial infarction, peripheral vascular disease with amputation, and fatal and nonfatal stroke, as well as a first cardiovascular event or death from any cause.
No safety signals were observed with daily fish oil supplementation, Dr. Lok reported, noting that there was no meaningful difference between the fish oil and placebo groups in incidence of adverse events or adherence to treatment.
In the interview, Dr. Lok said the positive effects of fish oil in this study may be explained by the specific patient population studied and the potential mechanisms of effect.
“Persons who are treated with chronic hemodialysis are at significantly higher risk for cardiovascular events than the general population,” Dr. Lok said. “They also have lower blood levels of omega-3, and have additional risk factors associated with being on hemodialysis—and not relevant in the general population—that may respond to fish oil supplementation.”
If these results are confirmed, Dr. Lok said, quick uptake of fish oil supplementation in patients receiving hemodialysis in clinical practice might be seen. “It should be emphasized that the dose and formulation of fish oil, and how it is taken, are important,” she said.
Disclosures
Charmaine E. Lok, MD, and co-authors reported that the PISCES study was supported by the Heart and Stroke Foundation of Canada and others. Commercial support included an in kind contribution from DSM, previously Ocean Nutrition Canada.
References
Lok C, Hemmelgarn B, Moist LM, et al. Protection Against Incidences of Serious Cardiovascular Events Study with daily fish oil supplementation in patients on dialysis (PISCES) [abstract]. Presented at: American Society of Nephrology Kidney Week 2025; November 6–9, 2025; Houston, TX.
Lok CE, Farkouh M, Hemmelgarn BR, et al, for the PISCES Investigators. Fish-oil supplementation and cardiovascular events in patients receiving hemodialysis. N Engl J Med. Published online November 7, 2025. doi:10.1056/NEJMoa2513032