Dialysis patients face a brutal calculus: their kidneys no longer work, so they spend hours hooked to machines that filter their blood. But their cardiovascular system pays a steep price for that survival. Now, a large international trial suggests something surprisingly simple might help — a daily fish oil supplement.
The study, called PISCES, followed 1,228 patients across 26 dialysis centers in Australia and Canada. Those taking four grams of fish oil daily — providing the omega-3 compounds EPA and DHA — saw a 43% reduction in major cardiovascular events compared to those on placebo. That includes heart attacks, strokes, cardiac deaths, and amputations from vascular disease. The findings were presented at the American Society of Nephrology Kidney Week 2025 and published simultaneously in The New England Journal of Medicine.
For context: dialysis patients have some of the highest cardiovascular risk of any patient group. Their damaged kidneys can't regulate blood pressure or fluid balance properly, and the dialysis process itself creates inflammation. Most experimental treatments for this population have failed. So a 43% reduction in serious events is genuinely rare territory.
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Dialysis patients typically have much lower levels of EPA and DHA in their blood than the general population — partly because kidney disease disrupts how the body processes these compounds. Kevan Polkinghorne, the nephrologist who led the Australian arm of the trial at Monash Health, puts it plainly: "In a field where many trials have been negative, this is a significant finding."
The mechanism isn't exotic. Fish oil's anti-inflammatory and blood-thinning properties address real problems in dialysis patients — chronic inflammation from the disease itself, and clotting risks from the vascular access points needed for treatment. By restoring EPA and DHA levels, the supplement appears to address a specific vulnerability in this population.
One important note: Polkinghorne emphasized that these results are specific to hemodialysis patients with kidney failure. The findings don't necessarily apply to healthy people taking fish oil, or to other patient groups. This is a common mistake — assuming a breakthrough in one population means everyone should follow suit.
The next question is implementation. Four grams daily is a meaningful commitment, and cost and tolerability will matter for real-world adoption. But for a population where cardiovascular complications are the leading cause of death, a therapy that cuts serious events by nearly half could reshape how dialysis care works.
