ESC Congress in Review - Main Edition 2019 - 29

ESC Congress 2019 In Review

Effects of Omega-3 Fatty Acids
on Arrhythmias in Diabetes
Patients: an Update
Written by Michiel Tent

Additional data from A Study of Cardiovascular Events
iN Diabetes (ASCEND) showed no effect on non-fatal
arrhythmias of 1 g daily of omega-3 fatty acid (FA) capsules in patients with diabetes and no known cardiovascular disease (CVD). There was no statistically significant
effect on atrial fibrillation (AF), nor on the composite
outcome of any cardiac arrhythmia. There may, however,
be a dose-related protective effect on coronary events.
Observational studies have suggested that higher
fish consumption may have a protective effect against
coronary heart disease (CHD). However, a meta-analysis
in	2018	of	10	large	randomised	trials	of	0.5	to	2	g	daily	
omega-3 FA supplementation (with EPA and DHA, found
in fish) did not show convincing benefit on CVD [Aung T
et al. JAMA Cardiol 2018].	Sarah	Parish,	BSc,	MSc,	DPhil,	
University of Oxford, United Kingdom, pointed out that
3 new large trials have since been reported. Evidence
from 12 low-dose studies showed a dose-dependent mean
reduction in the rate ratio (RR) of coronary heart disease
events	of	8%	(3%	to	13%)	per	1	g	daily.	In	addition,	the	
REDUCE-IT trial, applying a 4-g dose of a purified form of
EPA among participants with high triglyceride levels, also
reported a highly statistically significant 25% reduction
in	various	cardiovascular	outcomes	corresponding	to	7%	
(4% to 10%) per 1 g daily [Bhatt DL et al. N Engl J Med
2019]. In that study, however, supplementation was also
associated with a larger percentage of patients who were
hospitalised for AF or flutter (3.1% vs 2.1%, P = .004).

Secondary Analysis of ASCEND
In the original ASCEND study [ASCEND Study
Collaborative Group N Engl J Med 2018]	 there	 was	 no	
evidence, based on patient-reported outcomes, of an
effect of omega-3 FA supplementation on arrhythmias.
Prof. Parish presented a secondary analysis of ASCEND,
which assessed the effects of omega-3 FA supplementation on arrhythmias more comprehensively with
additional	data	for	97%	of	participants	with	linkage	to	
electronic Hospital Episode Statistics (HES) data during
the trial (and for 14 years before randomisation).
	 In	 ASCEND,	 15,480	 participants	 with	 diabetes	 but	
without atherosclerotic cardiovascular disease had
been randomised to 1 g omega-3 FA or matching placebo
daily. Almost all participants with known prior AF were
excluded. In the secondary analysis, key arrhythmia
outcomes considered were: 1) AF in participants without known prior AF; 2) non-fatal ventricular arrhythmia;
and 3) any non-fatal cardiac arrhythmia. During a mean
follow-up	of	7.4	years,	HES	data	captured	arrhythmias	
in	an	additional	1,137	participants	over	the	455	that	had	
self-reported arrhythmia adverse events during the trial. The incidence of non-fatal arrhythmias and cardiac
deaths are shown in Table 15.
Prof. Parish concluded that, in ASCEND, 1 g omega-3
FA did not show a statistically significantly effect on AF
or on the composite outcome of any non-fatal cardiac
arrhythmia. Prof. Parish added that systematic reporting of arrhythmia outcomes in existing and future trials
is warranted. The ongoing STRENGTH trial of 4 g daily
supplementation will add new insights after completion
in 2020.
Replay presentation on ESC365

Table 15. Effect of Omega-3 Fatty Acid Supplements on Arrythmias and Cardiac Deaths
Omega-3 FA
(n = 7,740)

Placebo
(n = 7,740)

n (%)*

n (%)*

595	(7.7%)

582	(7.6%)

1.02 (0.91 to 1.15)

Ventricular arrhythmia

81	(1.0%)

54	(0.7%)

1.49 (1.06 to 2.09)

Any cardiac arrhythmia

807	(10.4%)

769	(9.9%)

1.05 (0.95 to 1.16)

Coronary death

100 (1.3%)

127	(1.6%)

Non-coronary death

33 (0.4%)

42 (0.5%)

0.78	(0.50	to	1.23)

Any cardiac death

133	(1.7%)

169 (2.2%)

0.79	(0.63	to	0.98)

Non-fatal arrhythmias
Atrial fibrillation

Rate ratio (95% CI)

Cardiac deaths
0.79	(0.61	to	1.02)

* Participants with events.
CI, confidence interval; FA, fatty acid.

Official Peer-Reviewed Highlights From ESC Congress 2019

29
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ESC Congress in Review - Main Edition 2019

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