Public Release: 

Fish oils do not prevent heart attack or strokes in people with diabetes

European Society of Cardiology

Munich, Germany - 26 Aug 2018: Fish oil supplements do not prevent heart attacks or strokes in patients with diabetes, according to late breaking results from the ASCEND trial presented today in a Hot Line Session at ESC Congress 20181 and published in the New England Journal of Medicine.

In observational studies, higher consumption of fish is associated with lower risks of coronary artery disease and stroke. However, previous randomised trials have not been able to show that taking fish oil supplements containing omega-3 fatty acids reduce the risk of having cardiovascular events.

The ASCEND trial (A Study of Cardiovascular Events iN Diabetes)2 examined whether fish oil supplements reduce the risk of a cardiovascular event in patients with diabetes. Between 2005 and 2011, 15,480 patients with diabetes but no history of cardiovascular disease were randomly assigned to fish oil supplementation (1 g daily) or matching placebo.

The primary efficacy outcome was first serious vascular event, which included non-fatal heart attacks, non-fatal strokes or transient ischaemic attacks (sometimes called "mini-strokes"), or deaths from a cardiovascular cause (but excluding any intracranial haemorrhage; i.e. bleeding in the head or brain3).

During an average of 7.4 years of follow-up, a first serious vascular event occurred in 689 (8.9%) participants allocated fish oil supplements and 712 (9.2%) participants allocated placebo. There was no significant difference between the two groups: rate ratio of 0.97 (95% confidence interval 0.87-1.08, p=0.55).

Dr Louise Bowman, principal investigator, Nuffield Department of Population Health, University of Oxford, UK, said: "Our large, long-term randomised trial shows that fish oil supplements do not reduce the risk of cardiovascular events in patients with diabetes. This is a disappointing finding, but it is in line with previous randomised trials in other types of patient at increased risk of cardiovascular events which also showed no benefit of fish oil supplements. There is no justification for recommending fish oil supplements to protect against cardiovascular events."

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Notes to editors

SOURCES OF FUNDING: British Heart Foundation, Medical Research Council Population Health Research Unit (MRC-PHRU), Abbott, Bayer AG, Mylan, Solvay.

DISCLOSURES: The study was designed and run independently of the funders by the Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU) in the Nuffield Department of Population Health (NDPH). The lead investigators abide by the CTSU guidelines not to accept payment or honoraria from drug companies.

References

1 "ASCEND - A randomized trial of omega-3 fatty acids (fish oil) versus placebo for primary cardiovascular prevention in 15,480 people with diabetes" will be discussed during:

  • Press Conference - Hot Line - Late Breaking Clinical Trials 2 on Sunday 26 August at 09:30 CEST.
  • Hot Line Session 2 on Sunday 26 August at 16:45 to 17:45 CEST in the Munich Auditorium.
  • Meet the Trialist - ASCEND on Monday 27 August at 12:40 to 13:10 CEST on the ESC TV Stage in ESC Plaza.

2 ASCEND Study Collaborative Group. ASCEND: Characteristics of a randomized trial of aspirin and of omega-3 fatty acid supplementation in 15,480 people with diabetes. Am Heart J. 2018;198:135-144.

3 Fatal and nonfatal intracranial haemorrhage were excluded.

About the European Society of Cardiology

The European Society of Cardiology brings together health care professionals from more than 150 countries, working to advance cardiovascular medicine and help people lead longer, healthier lives.

About ESC Congress 2018

ESC Congress is the world's largest and most influential cardiovascular event contributing to global awareness of the latest clinical trials and breakthrough discoveries. ESC Congress 2018 takes place 25 to 29 August at the Messe München in Munich, Germany. Explore the scientific programme.

More information is available from the ESC Press Office at press@escardio.org.

About the Nuffield Department of Population Health (NDPH)

The Nuffield Department of Population Health (NDPH) is a world-leading research institute, based at the University of Oxford, that investigates the causes and prevention of disease. NDPH has over 500 staff working in a number of world-renowned population health research groups, including the Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU). For further information contact communications@ndph.ox.ac.uk.

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