Table 2. Incidence and Relative Hazards of AF Among Participants Randomized to EPA-DHA vs Placebo.

End points	EPA-DHA (n = 12 542)			Placebo (n = 12 577)			EPA-DHA vs placebo
	No. of events	Total person-years	Events per 1000 person-years	No. of events	Total person-years	Events per 1000 person-years	Difference in events per 1000 person-years (95% CI)	Hazard ratio (95% CI)a	P value
Primary end point
All incident AF	469	64 942	7.2	431	65 242	6.6	0.6 (−0.3 to 1.5)	1.09 (0.96-1.24)	.19
Sensitivity analyses of primary end point
AF events excluding those with symptoms preceding randomization	440	64 840	6.8	402	65 154	6.2	0.6 (−0.3 to 1.5)	1.10 (0.96-1.26)	.17
AF events excluding those detected by CMS linkage data alone	389	64 676	6.0	345	64 970	5.3	0.7 (−0.1 to 1.5)	1.13 (0.98-1.31)	.10
AF events excluding atrial flutter alone and postoperative AFb	410	64 721	6.3	374	65 055	5.7	0.6 (−0.3 to 1.4)	1.10 (0.96-1.27)	.18
AF events excluding those without ECG confirmationb	346	64 587	5.4	310	64 875	4.8	0.6 (−0.2 to 1.4)	1.12 (0.96-1.30)	.15
On-treatment analysisc	403	51 005	7.9	358	51 223	7.0	0.9 (−0.1 to 2.0)	1.13 (0.98-1.30)	.09
Secondary end points
Paroxysmal AF	271	64 942	4.2	255	65 242	3.9	0.3 (−0.4 to 1.0)	1.07 (0.90-1.27)	.46
Nonparoxysmal AF	182	64 942	2.8	164	65 242	2.5	0.3 (−0.3 to 0.8)	1.11 (0.90-1.37)	.32

Abbreviations: AF, atrial fibrillation; CMS, Centers for Medicare & Medicaid Services; DHA, docosahexaenoic acid; ECG, electrocardiographic; EPA, eicosapentaenoic acid.

^aThe hazard ratio for each intervention was estimated in Cox models using indicators for treatment group, controlling for the second intervention, age, and sex.

^bPost hoc analyses.

^cAdherence-based analyses that censored follow-up data when a participant discontinued trial capsules or began taking nonstudy fish oil supplements.