Can fish oil reduce heart complications in dialysis patients?

A new study published in ‘The New England Journal of Medicine’ has found that taking a daily fish oil supplement can significantly reduce the risk of serious cardiovascular complications in people undergoing hemodialysis for kidney failure. The results are particularly significant given that cardiovascular disease remains the leading cause of death among people with kidney failure. 

Chronic kidney disease affects an estimated 10 per cent of the global population, and more than 20 lakh people worldwide currently receive dialysis or a kidney transplant. However, this figure is believed to represent only about one-tenth of those who actually require life-saving renal replacement therapy. Against this backdrop, the new study could have important implications for improving survival and quality of life among patients with end-stage kidney disease.

What the study found

The study, known as the PISCES trial, was a large, double-blind, randomised, placebo-controlled study designed to assess whether omega-3 fatty acid supplementation, or fish oil supplements, could reduce cardiovascular events in patients receiving maintenance hemodialysis. It was conducted across Canada and Australia by researchers from Monash Health, the School of Clinical Sciences at Monash University, and international collaborators, and the findings were presented at the American Society of Nephrology Kidney Week 2025, representing one of the most robust demonstrations to date of cardiovascular risk reduction in dialysis patients.

Researchers enrolled a total of 1,228 adult patients from 26 dialysis centres across Canada and Australia between November 2013 and July 2019. Of these participants, 610 were randomly assigned to receive a daily fish oil supplement, while 618 were assigned to receive a corn oil placebo. These omega-3 fatty acids are known for their anti-inflammatory and cardioprotective properties in the general population, but until now, their effectiveness in patients undergoing hemodialysis had remained uncertain.

The primary endpoint of the trial was a composite measure of all serious cardiovascular events. This included sudden and non-sudden cardiac death, fatal and nonfatal myocardial infarction, peripheral vascular disease leading to amputation, and fatal and nonfatal stroke. Secondary endpoints expanded this composite to include non-cardiac causes of death, as well as analyses of individual cardiovascular outcomes and overall mortality.

Over a median follow-up period of 3.5 years, the researchers observed a striking reduction in cardiovascular risk among patients who received fish oil supplementation. The rate of serious cardiovascular events was significantly lower in the fish-oil group compared with the placebo group, at 0.31 versus 0.61 events per 1,000 patient-days. This indicated that patients who received fish oil had a substantially lower risk of serious cardiovascular events than those given a placebo.

When the researchers broadened their analysis to include deaths from non-cardiac causes, the benefit of fish oil supplementation was still clear. Patients who took fish oil had a lower overall risk of death or serious cardiovascular events compared with those given a placebo. The study also found consistent benefits across specific heart- and blood vessel–related outcomes. The risk of dying from heart-related causes was nearly halved, while the chances of having a heart attack were also substantially lower. Fish oil supplementation was linked to fewer cases of severe blood vessel disease requiring amputation, and the strongest protective effect was seen for stroke, with patients taking fish oil facing a much lower risk than those in the placebo group.

Importantly, patients who took fish oil were also less likely to experience their first major cardiovascular event or die from any cause during the study. Overall, the risk was about 27 per cent lower in the fish-oil group compared with those who received a placebo. Adherence to the supplementation regimen was high, and the incidence of adverse events did not differ meaningfully between the fish-oil and placebo groups, suggesting that the intervention was both effective and safe.

Summarising the findings, the authors wrote, “The rate of serious cardiovascular events among participants receiving maintenance hemodialysis was lower with daily supplementation with n-3 fatty acids than with placebo.”

Participants who took four grams of fish oil daily experienced an overall 43 per cent reduction in serious cardiovascular events compared with those receiving a placebo. These outcomes encompassed heart attacks, strokes, cardiac-related deaths, and vascular-related amputations - events that account for a substantial proportion of morbidity and mortality in dialysis populations.

The Australian arm of the trial was led by Adjunct Professor Kevan Polkinghorne, a nephrologist at Monash Health and adjunct professor in the School of Clinical Sciences at Monash University. Highlighting the importance of the findings, Professor Polkinghorne said, “Patients on dialysis have extremely high cardiovascular risk, and very few therapies have been shown to reduce that risk. In a field where many trials have been negative, this is a significant finding.”

However, Professor Polkinghorne cautioned against generalising the findings beyond the study population. He emphasised that the results apply specifically to patients receiving hemodialysis for kidney failure and should not be extrapolated to healthy individuals or other patient groups without further evidence.

The Australian component of the study was funded by the National Health and Medical Research Council, while overall coordination of the PISCES trial was managed by the Australasian Kidney Trials Network. Approximately 200 Australian patients participated, including 44 treated at Monash Health. International leadership of the trial came from Professor Charmaine Lok and colleagues at the University Health Network in Toronto and the University of Calgary.

Why it matters

The significance of the PISCES trial becomes clearer when viewed in the context of the growing global burden of chronic kidney disease and its strong association with cardiovascular mortality. A 2023 Global Burden of Disease analysis estimated that approximately 78.8 crore adults aged 20 years and older were living with chronic kidney disease worldwide. In the same year, CKD ranked as the ninth leading cause of death globally, underscoring its escalating public health impact.

The analysis also highlighted the close link between kidney disease and heart disease. Impaired kidney function was estimated to account for around 11.5 per cent of all cardiovascular deaths globally. In absolute terms, CKD was responsible for approximately 14.8 lakh deaths in 2023, with a substantial proportion of these deaths driven by cardiovascular complications rather than kidney failure alone.

India carries one of the heaviest burdens of kidney disease worldwide. In India, an estimated 13.8 crore adults in India were living with CKD in 2023, making it the country with the second-highest national burden. The condition is a major contributor to cardiovascular disease and premature death, particularly among patients who progress to end-stage renal disease and require dialysis.

Evidence from Indian clinical studies further underscores the scale of the problem. A 2025 study examining cardiovascular disease prevalence among CKD and ESRD patients in India found alarmingly high rates of cardiac and vascular complications. The cross-sectional study, conducted at Acharya Vinoba Bhave Rural Hospital between January 2022 and December 2023, included 800 adult patients with CKD stages 3 to 5, both with and without dialysis.

The researchers reported that 35 per cent of participants had coronary artery disease, 27.5 per cent had heart failure, 20 per cent had arrhythmias, and 15 per cent had cerebrovascular disease. Cardiovascular disease prevalence was significantly higher among patients with end-stage renal disease compared to those with earlier stages of CKD. Using logistic regression analysis, the study identified age, hypertension, diabetes, dyslipidaemia, and ESRD status as significant predictors of cardiovascular disease.

Notably, patients with ESRD had more than double the odds of developing cardiovascular disease compared with those with less advanced kidney disease. The authors concluded, “This study reveals a high burden of CVD among CKD and ESRD patients in India, particularly in those with ESRD. Early identification and management of cardiovascular risk factors in CKD patients are crucial to reducing the risk of complications.”

In India, the government is addressing chronic kidney disease through the Pradhan Mantri National Dialysis Program and Ayushman Bharat–PMJAY, providing free or subsidised dialysis and health coverage. PMNDP supports states with financial and technical assistance, covering 1,609 centres and over 27 lakh patients so far. AB PMJAY offers up to Rs 5 lakh per family annually for treatment, including for senior citizens above 70. Initiatives like free medicines, diagnostics, and price regulation for CKD drugs further improve access and reduce out-of-pocket expenses.

This story is done in collaboration with First Check, which is the health journalism vertical of DataLEADS.