Health 19/12/2025 15:48

Expanded Summary of the PISCES Trial

The PISCES randomized clinical trial, published in The New England Journal of Medicine in November 2025, enrolled 1,228 adults on maintenance hemodialysis across 26 sites in Canada and Australia. Participants were randomized to receive either 4 g of fish oil daily (providing ~1.6 g EPA and 0.8 g DHA) or a placebo (corn oil). Over a median follow-up of 3.5 years, the fish oil group experienced a 43% lower rate of major cardiovascular events compared with placebo.

Cardiovascular Outcomes

The reduction in risk was consistent across multiple endpoints:

Myocardial infarction (heart attack)
Stroke
Cardiovascular death
Peripheral vascular amputations

Notably, the trial reported no meaningful increase in adverse events, suggesting that fish oil supplementation was well tolerated in this population.

Why Dialysis Patients?

Researchers emphasized that the benefits were specific to patients with kidney failure on dialysis, who face an exceptionally high cardiovascular risk and often have low baseline omega-3 fatty acid levels. In contrast, large-scale studies in the general population have shown mixed or minimal benefits of fish oil supplementation for cardiovascular prevention. This underscores the importance of tailoring interventions to specific patient groups rather than assuming universal applicability.

Clinical Implications

Potential breakthrough: For dialysis patients, who have limited effective options for reducing cardiovascular risk, fish oil supplementation could represent a simple, low-cost intervention.
Caution required: Experts stress that replication in other cohorts and longer-term studies are needed before widespread clinical adoption. The trial’s findings, while robust, must be confirmed to ensure reliability.

Comparison Table

Aspect	Fish Oil (PISCES Trial)	Conventional Approaches in Dialysis
Population	1,228 adults on maintenance hemodialysis	Dialysis patients worldwide
Intervention	4 g fish oil daily (EPA + DHA)	Standard cardiovascular risk management (blood pressure control, statins, antiplatelets)
Follow-up	~3.5 years	Variable, often lifelong
Outcome	43% reduction in serious CV events	Modest benefit; high residual risk remains
Safety	No meaningful increase in adverse events	Known side effects from drugs (bleeding risk, muscle pain, etc.)
Generalisability	Specific to dialysis patients	Broader but less effective in this group

Conclusion

The PISCES trial provides compelling evidence that fish oil supplementation can significantly reduce cardiovascular complications in dialysis patients, a population with few effective preventive strategies. However, experts caution against extrapolating these findings to the general population. Replication and further investigation are essential before fish oil can be recommended as a standard therapy in nephrology practice.