A landmark international trial has found that high-dose fish oil supplementation significantly reduces serious cardiovascular events in patients receiving maintenance hemodialysis, a population at exceptionally high risk of heart-related complications. The findings provide rare evidence that a preventive therapy may meaningfully improve outcomes for these vulnerable patients.
Reduction in Cardiovascular Events and Death
The double-blind, placebo-controlled PISCES trial enrolled 1,228 adults undergoing long-term hemodialysis across 26 sites in Canada and Australia. Participants received either a daily 4-gram fish oil supplement containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) or a corn-oil placebo.
Over 3.5 years of follow-up, patients in the fish oil group experienced significantly fewer serious cardiovascular events. The rate was 0.31 events per 1,000 patient-days, compared with 0.61 events in the placebo group, translating to a 43% relative risk reduction. Benefits were seen across multiple cardiovascular outcomes, including cardiac death, myocardial infarction, stroke, and peripheral vascular disease requiring amputation. An extended composite outcome that included non-cardiac death also favored fish oil, suggesting a broad protective effect.
High Adherence and Comparable Safety Profile
Adherence to the treatment regimen was high and similar across both groups. Importantly, adverse events did not differ meaningfully between the fish oil and placebo arms, supporting the safety and tolerability of long-term fish oil use in patients who already face a substantial treatment burden.
A Potential New Cardiovascular Strategy in Kidney Failure
Cardiovascular disease is the leading cause of death among people receiving hemodialysis, and few interventions have demonstrated consistent preventive benefits. The PISCES results stand out as some of the strongest evidence supporting a simple, widely accessible therapy that may reduce morbidity and mortality.
The magnitude of benefit observed in this study appears greater than that reported in general population trials, underscoring the urgent need for effective cardiovascular protection in advanced kidney disease. Further research is expected to determine which patients may benefit most and how best to optimize dosing strategies.
Reference
Lok CE et al. Fish-Oil Supplementation and Cardiovascular Events in Patients Receiving Hemodialysis. NEJM. 2025; 10.1056/NEJMoa2513032.
