Vitamin D or omega 3 fatty acids do not prevent AF

Vitamin D or omega-3 fatty acid supplementation are commonly used, but findings from the VITAL Rhythm trial do not support their use for the primary prevention of atrial fibrillation (AF) [1]. The results from this first-of-its-kind AF primary prevention randomised controlled trial were highly anticipated.

Marine omega-3s and vitamin D have been implicated in upstream biologic processes involved in electrical and structural remodelling of the atria. In observational studies, patients with low levels of these nutrients tend to have an elevated risk of AF. Dietary supplements have appeal in primary prevention given the relative ease of administration to broad populations. The VITAL Rhythm Study (NCT02178410) is an ancillary trial of the VITAL trial. The VITAL trial tested daily supplementation with 2000 IU of vitamin D₃ and/or 840 mg of omega-3 fatty acids (Omacor 1g/d; 465 mg eicosapentaenoic acid [EPA] + 375 mg of docosahexaenoic acid [DHA]) for the prevention of cardiovascular disease. From this trial, 25,119 participants without a history of AF were enrolled in the VITAL Rhythm Study. Mean age was 67 years, 51% were women, 21% Black. The primary endpoint was incident AF. At the time of presentation, the VITAL Rhythm Study had 92% power to detect a 20% reduction or increase in the observed HR for incident AF.

Over 5.3 years of treatment, 3.6% (n=900) of the study population had a confirmed AF event. In 58.4% (n=526) it was paroxysmal, in 38.4% (n=346) persistent. Symptoms were present at diagnosis in 61.9% of cases (n=557). An intention-to-treat analysis revealed no benefit from EPA/DHA on the risk of new-onset AF. In fact, as first author Prof. Christine Albert (Cedars-Sinai Medical Center, USA) pointed out, the risk was slightly higher than placebo: HR 1.09 (95% CI 0.96–1.24; P=0.19). The result was very similar for vitamin D₃: HR 1.09 (95% CI 0.96–1.25; P=0.19). Prof. Albert said that these findings do not support the use of EPA/DHA or vitamin D₃ for the primary prevention of incident AF, but neither do they show an increased risk for patients who use these supplements for other indications. A sensitivity analysis of on-treatment incidence alone showed a trend for more AF events in the EPA/DHA group: HR 1.13 (95% CI 0.98–1.30; P=0.09). These findings add to the negative primary results of the VITAL trial [2]. Prof. Albert added that future primary prevention AF trials are needed to test other prophylactic strategies.

 

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   1. Albert CM, et al. The Vital Rhythm Trial: Omega-3 Fatty Acid and Vitamin D Supplementation in the Primary Prevention of Atrial Fibrillation. LBS.01, AHA Scientific Sessions 2020, 13–17 Nov.
   2. Manson JE, et al. N Engl J Med. 2019;380(1):33–44.

Posted on 17 February 202118 February 2021