Patients on maintenance hemodialysis receiving daily fish oil had significantly lower rates of serious cardiovascular events than those receiving placebo, according to the PISCES trial, presented at the American Society of Nephrology Kidney Week Annual Meeting and simultaneously published Nov. 7 in NEJM.

Charmaine Lok, MD, et al., randomized 1,228 adults (mean age, 64 years; 37% women) on maintenance hemodialysis across 26 sites in Canada and Australia to receive either daily oral supplementation with fish oil (4 g n−3 polyunsaturated fatty acids [1.6 g EPA, 0.8 g DHA]; n = 610) or corn oil placebo (n= 618).

Results showed that at 3.5 years, the rate of serious cardiovascular events (primary endpoint), was 43% lower in the fish oil group vs. the placebo group (0.31 vs. 0.61 per 1,000 patient-days; hazard ratio [HR], 0.57; 95% CI, 0.47-0.70; p<0.001). Including noncardiac causes of death also yielded a lower HR of 0.77 (95% CI, 0.65-0.90) compared with placebo.

Specifically, individual components of the primary endpoint were reduced in the fish oil group vs. placebo, including sudden and nonsudden cardiac death (HR, 0.55), fatal and nonfatal myocardial infarction (HR, 0.56), peripheral vascular disease leading to amputation (HR, 0.57), fatal and nonfatal stroke (HR, 0.37) and first cardiovascular event or death from any cause (HR, 0.73).

Notably, findings also revealed that those taking fish oil had a significantly reduced risk of serious cardiovascular events whether they had a history of a previous cardiovascular event (HR, 0.50; 95% CI 0.37-0.67) or not (HR, 0.55; 95% CI, 0.40-0.76).

Regarding safety, 4.8% of the fish oil group had serious bleeding vs. 7.6% in the placebo group. Other serious adverse events and adherence rates were similar between groups.

In an accompanying editorial comment, Finnian R. Mc Causland, MB, BCh, MMSc, and David M. Charytan, MD, write, "Given the successful completion of PISCES, a confirmatory trial seems achievable and is certainly indicated." In the meantime, they note physicians may want to recommend fish oil supplementation to these patients "but history suggests that we should exercise caution until we are sure that there is truly a fish on the line."