Fish Oil Supplementation Reduces Cardiovascular Events by 43% in Dialysis Patients, PISCES Trial Shows
核心洞察
The PISCES trial demonstrated that 4g daily fish oil supplementation significantly reduced cardiovascular events by 43% in hemodialysis (搜索) patients over 3.5 years of follow-up.
Fish oil supplementation lowered risks across all individual cardiovascular endpoints, including cardiac death (45% reduction), myocardial infarction (搜索) (44% reduction), and stroke (搜索) (63% reduction).
The results stand out as remarkably strong compared to other cardiovascular interventions, prompting calls for replication studies to confirm the findings in this high-risk patient population.
Hemodialysis (搜索) patients receiving 4 grams of daily fish oil supplementation experienced a 43% reduction in serious cardiovascular events compared to placebo, according to results from the PISCES trial presented at ASN Kidney Week and published simultaneously in The New England Journal of Medicine.
The double-blind, randomized, placebo-controlled trial enrolled 1,228 patients across 26 sites in Canada and Australia between 2013 and 2019. Patients on maintenance hemodialysis (搜索) were randomized to receive either four 1-gram capsules containing 1.6g EPA and 0.8g DHA daily, or citrus-flavored corn oil placebo.
Striking Cardiovascular Benefits Observed
Over 3.5 years of follow-up, the fish oil group demonstrated significantly lower rates of the primary composite endpoint—including sudden and nonsudden cardiac death, fatal and nonfatal myocardial infarction (搜索), peripheral vascular disease (搜索) leading to amputation, and fatal and nonfatal stroke (搜索)—compared to placebo (0.31 vs 0.61 per 1,000 patient-days; HR 0.57; 95% CI 0.47-0.70).
"The results are quite striking," said lead author Charmaine Lok, MD, professor of medicine at the University of Toronto and senior scientist at the Toronto General Hospital Research Institute (搜索). "Patients who are on hemodialysis (搜索) have the lowest levels of omega-3 fatty acids recorded in the medical literature. Perhaps one of the effects is that we're able to bring it up to baseline or even above, and then to allow for those cardioprotective effects."
All individual cardiovascular endpoints significantly favored fish oil supplementation:
- Cardiac death: 45% risk reduction (HR 0.55; 95% CI 0.40-0.75)
- Fatal and nonfatal myocardial infarction: 44% reduction (HR 0.56; 95% CI 0.40-0.80)
- Peripheral vascular disease leading to amputation: 43% reduction (HR 0.57; 95% CI 0.38-0.86)
- Fatal and nonfatal stroke: 63% reduction (HR 0.37; 95% CI 0.18-0.76)
Addressing Critical Unmet Need
The findings address a significant clinical gap for dialysis patients, who face a 20-fold higher risk of cardiovascular death compared to the general population. "There really is no recommendation in terms of should you take fish oil supplementation or not, particularly in capsule form," Lok noted during the press briefing.
The study population included 610 patients in the fish oil group (mean age 64.1 years; 62.2% men; 40% white) and 618 in the placebo group (mean age 64.5 years; 63.1% men; 39.5% white). Just over one-third had a history of cardiovascular events, with mean baseline LDL cholesterol and triglyceride levels of 1.9 mmol/L and 1.3 mmol/L, respectively.
Safety Profile and Adherence
The intervention demonstrated a favorable safety profile, with bleeding rates actually lower in the fish oil group (4.8%) compared to placebo (7.6%). No differences were reported between groups for other serious adverse events. Analysis confirmed that the fish oil supplements effectively raised blood concentrations of omega-3 polyunsaturated fatty acids.
Mechanism and Future Research
Lok hypothesized that the high-dose, pure fish oil formulation may have improved both traditional and nontraditional risk factors common in hemodialysis (搜索) patients, including atherogenic lipids, inflammation, and oxidative stress. The supplements may also have reduced acute thrombotic event risk.
"What we really need to do is try to look into the mechanisms of action," Lok told Healio. "We have a lot of data, and I think there's a lot of work for us to unravel the effects and why they occurred."
Expert Commentary and Caution
The magnitude of benefit has drawn both attention and skepticism from the cardiovascular community. Steven Nissen, MD, primary investigator of the STRENGTH trial, called the results "implausibly good," noting he had "never seen a hazard ratio of 0.57 with any therapy—the most powerful statin and the most powerful PCSK9 inhibitor."
In an accompanying editorial, Finnian Mc Causland and David Charytan questioned how such remarkable results could be explained when many other interventions have failed in this population. While acknowledging the confidence intervals suggest findings are not due to chance, they cautioned that "contemporary medicine is replete with examples in which potentially practice-changing, outsized results of early trials have failed to be replicated."
The editorialists suggested pausing before accepting such remarkable results, emphasizing the need for replication studies to confirm these findings in the high-risk dialysis population.