Omega-3 Without Effect in Short-Term Study after Myocardial Infarction
Reference:
Rauch, B. et al., Circulation, 122: 2152-2159 , 2010
Institut fur Herzinfarktforschung Ludwigshafenan der Universitat Heidelberg,Ludwigshafen, Germany
Summary:
This randomized, placebo-controlled , double-blind, multicenter clinical trial from Germany was designed to evaluate the potential effectiveness of EPA/DHA omega-3 supplementation (provided as ethyl ester forms) on the rate of sudden cardiac death when given to survivors of a myocardial infarction on top of standard medical treatment. The omega-3 dose was 840 mg/day (460 mg EPA plus 380 mg DHA) given for a period of 365 days. A total of 1919 and 1885 patients in each group completed the study (having an average age of 64 years, 74 % male).
At one year, the rate of sudden cardiac death (all patients) was 1.5 % of the population and the total mortality was 4.2 % with no significant difference between the omega-3 versus the control (placebo) groups. The authors commented that differences in the specific clinical conditions of the target patient population and other factors may explain why other studies have found significant benefits with omega-3 supplementation. One of these studies included the GISSI trial (The Lancet , 354: 447 – 455 (1999)) which employed a larger patient population and extended for 3.5 years. The authors of the present OMEGA trial also stated that they would have needed to enroll approximately 20,000 patients to confidently observe a benefit of a 30 % reduction in sudden cardiac death due to omega-3 fatty acid supplementation.
It is noted that the patients in both groups significantly increased their fish consumption upon initiation of the OMEGA trial such that 45 % were consuming several servings per week by the end of the study. It would have been of interest to evaluate the outcomes in those patients who continued to consume very little or no fish throughout the trial. Further, the measurement of omega-3 levels in blood samples throughout the trial (at least at the beginning and end) would have helped to better define the actual omega-3 status of the individual patients at the physiological level. In this regard, previous study has indicated that the risk of sudden death was markedly lower in those subjects with omega-3 levels in whole blood (EPA plus DPA plus DHA) which were 6.1-10.2 % of total fatty acids as compared to those with much lower levels ( Albert et al., New Engl. J. Med., 346: 1113 (2002)).