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Even a modest 10% reduction in heart disease mortality in this group "would justify treatment with a relatively safe therapy," stated advisory committee chair David S. Siscovick, MD, of the New York Academy of Medicine in New York City, and colleagues.
"Although recent RCT [randomized controlled trial] evidence from randomized controlled trials has raised questions about the benefits of omega-3 supplementation to prevent clinical cardiovascular disease events, the recommendation for patients with prevalent coronary heart disease such as a recent myocardial infarction remains essentially unchanged," they wrote online in Circulation.
However, people in the general population who choose to take omega-3 fish oil supplements are doing so “in the absence of scientific data that shows any benefit of the supplements in preventing heart attacks, stroke, heart failure or death for people who do not have a diagnosis of cardiovascular disease,” Siscovick noted in a news release. "We cannot make a recommendation to use omega-3 fish oil supplements for primary prevention of cardiovascular disease at this time."
The update to prior recommendations also states that clinicians should consider the use of omega-3 PUFA supplementation in patients with heart failure. This new recommendation is based on evidence from the 2008 GISSI-HF trial, which reported that supplementation reduced mortality and hospitalizations by 9% in patients with a left ventricular ejection fraction of less than 40%.
The findings, despite limited generalizability, suggest "that omega-3 PUFA supplementation may reduce heart failure-related hospitalizations and death in patients with heart failure with reduced ejection fraction," Siscovick's group noted, adding that more trials are needed "to determine whether the benefits of omega-3 PUFA supplementation on prognosis vary according to the type, severity, and cause of heart failure."
They pointed out that heart failure is a heterogeneous disorder, particularly among older adults and women.
As far as primary prevention of CVD, there was no new evidence to support supplementation since the American Heart Association (AHA) issued a scientific statement in 2002, the authors said.
In 2002, the AHA recommended that patients with documented coronary heart disease (CHD) consume approximately 1 g/day of eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA), preferably from oily fish. Alternatively, it was recommended that these supplements "could be considered in consultation with a physician."
This recommendation on supplementation still stands, the advisory authors said.
For the current update, the committee focused exclusively on large randomized controlled trials (RCTs) of omega-3 PUFA supplementation with major clinical cardiovascular disease endpoints. They included two studies published before 2002 and 13 published since 2002. Most secondary prevention studies used approximately 1,000 mg/day doses of omega-3 fatty acids, they noted.
They also stressed that they do not recommend omega-3 PUFA for preventing incident stroke among patients at high CVD risk and recurrent atrial fibrillation (AF).
"Because there are no reported RCTs related to the primary prevention of CHD, heart failure, and AF, we were not able to make recommendations for these indications," they explained.
The authors noted that they were unable to reach consensus on a recommendation for patients at high CVD risk.
There was also no scientific evidence from studies such as the large Outcome Reduction With Initial Glargine Intervention (ORIGIN) trial to support recommendations for the use of omega-3 PUFA supplements to prevent heart disease in patients with type 2 diabetes and pre-diabetes.
However, the ongoing (Study of Cardiovascular Events in Diabetes) ASCEND trial in the U.K. is examining the impact of omega-3 PUFA supplements on cardiovascular events among patients with diabetes who are free of prior clinical CVD, they pointed out.
Clinician-recommended treatments should be evidence-based and patients "should be informed of what is known and not known," Siscovick emphasized in an email to MedPage Today.
Certainly, patient preferences need to be taken into consideration, he said. However, some patients "need to be aware that some claims of health benefits of supplements may go beyond available data," he told MedPage Today. "Clinicians should read the advisory. It should impact their practice and discussions with patients."
At present, no specific guidelines on the use of fish oil supplementation have been issued by the United States Preventive Services Task Force, the American Academy of Family Physicians, or the American College of Physicians.
- Reviewed by Henry A. Solomon, MD, FACP, FACC Clinical Associate Professor, Weill Cornell Medical College and Dorothy Caputo, MA, BSN, RN, Nurse Planner