OMEMI: Omega-3 fatty acids fail to reduce CV events, mortality in elderly MI survivors
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Omega-3 fatty acids yielded no reductions in subsequent CV events or death in older patients with prior MI, according to findings presented at the virtual American Heart Association Scientific Sessions.
“Elderly people remain at significantly increased risk after acute myocardial infarction compared to younger subjects,” Are A. Kalstad, MD, of the University of Oslo – Oslo University Hospital, in Ullevaal, Norway, said during a press conference. “There is room for improvement in secondary prevention of myocardial infarction in elderly patients.”
Kalstad said while high intake of marine omega-3 polyunsaturated fatty acids has been associated with reduced risk for subsequent CV events, data on their impact have been mixed. Moreover, he noted that studies showing the impact of this intervention in this “vulnerable population” are lacking.
The group hypothesized that a dietary supplement of 1.8 g of marine omega-3 polyunsaturated fatty acids may reduce MI risk.
The multicenter, randomized, placebo-controlled, double-blind trial included 505 patients in the active treatment arm and 509 patients treated with placebo. Eligible participants were aged 70 to 82 years (mean age, 75 years; 29% women) and had experienced an MI 2 to 8 weeks before enrollment. The predefined follow-up time for all patients was 2 years.
The primary outcome was a composite of nonfatal MI, unscheduled revascularization, stroke, hospitalization for HF or all-cause death. The key secondary endpoint was new-onset AF, while major bleeding was the main safety outcome. The researchers also conducted an adherence assessment of serum fatty acids eicosapentaenoic/docosahexaenoic acid (EPA/DHA) before and after intervention.
There was no difference between the study arms in the primary composite outcome (HR = 1.07; 95% CI, 0.82-1.4; P = .62). There were also no differences in all-cause mortality (HR = 1.01; 95% CI, 0.6-1.71; P = .97).
There was a trend toward elevated risk for AF in the omega-3 fatty acids group (HR = 1.84; 95% CI, 0.98-3.44; P = .06), according to Kalstad.
Serum measurements of EPA/DHA were available for 87% of the cohort and “support good adherence,” Kalstad added.
“Omega-3 fatty acids did not reduce cardiovascular events or death in elderly patients after myocardial infarction,” Kalstad said at the press conference.
The broad inclusion criteria were a striking component of this study, according to Alberico L. Catapano, MD, PhD, of the University of Milano, Italy. “The inclusivity of OMEMI, everyone was in the trial, the inclusion criteria was only age and if they had myocardial infarction,” he said.
Catapano raised the question of how to reconcile the OMEMI findings with those from REDUCE-IT, which showed a “quite large” treatment effect of icosapent ethyl (Vascepa, Amarin) for hypertriglyceridemia. “One of the issues at hand is whether icosapent ethyl produces higher EPA levels. Another is whether DHA is less biologically active. This is a possibility,” he said.
REDUCE-IT also included a mineral oil placebo control group, which may have led to “exaggerated efficacy” of icosapent ethyl, according to Catapano. “The jury is still out on that one,” he said.
Whether the dose make a difference is for future researchers to consider, he said.
Perspective
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Kim Allan Williams Sr., MD, MACC, FAHA, MASNC, FESC
The big news here is that the Omega-3’s again have disappointed. We thought they would improve a variety of things — cognitive function, MIs, atrial fibrillation, believe it or not — but improved outcomes including in mortality have been difficult to arrive at.
In REDUCE-IT, an agent with EPA alone seemed to show substantial benefit, and so we were thinking there was a role for it. But now we have two trials, this one and STRENGTH, that show no improvement with omega-3 fatty acids. If you think of the populations where you are going to get the best improvement, you think of older people or those with previous MI. No question, this cohort is a high-risk group and the agents did basically nothing. The signal was for increased AF; nobody wants that.
It turns out that REDUCE-IT used mineral oil, which has been shown to have adverse cardiometabolic effects in terms of dyslipidemia, as a placebo. So, the benefit that we saw in that trial might not have been the fish oil being good, but the placebo being bad. That throws a little bit of a monkey wrench into where we are now.
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Kalstad A, et al. LBS.04: Fish oil, fancy drugs and frustrations in lipid management. Presented at: American Heart Association Scientific Sessions; Nov. 13-17, 2020 (virtual meeting).
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