Table 4.

Sex- and Race-Stratified Risks of Sudden Cardiac Death by Atrial Fibrillation Status, Atherosclerosis Risk in Communities Study (ARIC) and Cardiovascular Health Study (CHS)

		Incident AF through 2001, ARIC			Incident AF through 2006, CHS			Meta-Analysis
		No	Yes	P Value	No	Yes	P Value	HR (95% CI)	P Value	P Value for hetero- geneity
By sex
Female
Number of SCD events		83	9		93	26
Person-years		103852	4561		36831	2973
Incidence rate(95% CI)^c		0.80 (0.64–0.99)	1.97 (0.97–3.60)		2.53 (2.06–3.09)	8.74 (5.95–12.84)
Hazard ratio (95% CI)	Model 1^a	1 [Referent]	6.63 (3.13–14.00)	<.001	1 [Referent]	2.86 (1.82–4.48)	<.001	3.58 (2.43–5.26)	<.001	.06
	Model 2^b	1 [Referent]	4.12 (1.91–8.90)	<.001	1 [Referent]	2.49 (1.57–3.95)	<.001	2.85 (1.92–4.23)	<.001	.27
Male
Number of SCD events		155	22		132	41
Person-years		79235	6158		22046	2609
Incidence rate(95% CI)^c		1.96 (1.67–2.28)	3.57 (2.30–5.31)		5.99 (5.05–7.10)	15.71 (11.57–21.34)
Hazard ratio (95% CI)	Model 1^a	1 [Referent]	5.01 (3.13–8.00)	<.001	1 [Referent]	2.35 (1.62–3.40)	<.001	3.14 (2.35–4.21)	<.001	.02
	Model 2^b	1 [Referent]	3.12 (1.93–5.04)	<.001	1 [Referent]	1.99 (1.37–2.91)	<.001	2.36 (1.76–3.18)	<.001	.15
By race
Non-Black
Number of SCD events		136	20		175	61
Person-years		135086	8879		50528	5031
Incidence rate(95% CI)^c		1.01 (0.85–1.19)	2.25 (1.42–3.41)		3.46 (2.99–4.02)	12.12 (9.43–15.58)
Hazard ratio (95% CI)	Model 1^a	1 [Referent]	4.38 (2.66–7.23)	<.001	1 [Referent]	2.61 (1.92–3.54)	<.001	3.01 (2.32–3.90)	<.001	.08
	Model 2^b	1 [Referent]	2.49 (1.49–4.17)	<.001	1 [Referent]	2.16 (1.59–2.96)	<.001	2.24 (1.72–2.93)	<.001	.64
Black
Number of SCD events		102	11		50	6
Person-years		48000	1840		8349	551
Incidence rate(95% CI)^c		2.13 (1.74–2.57)	5.98 (3.17–10.35)		5.99 (4.53–7.90)	10.89 (4.89–24.24)
Hazard ratio (95% CI)	Model 1^a	1 [Referent]	8.39 (4.42–15.91)	<.001	1 [Referent]	1.83 (0.77–4.34)	.17	4.89 (2.92–8.18)	<.001	.006
	Model 2^b	1 [Referent]	5.77 (2.96–11.24)	<.001	1 [Referent]	2.01 (0.81–4.97)	.14	3.98 (2.33–6.82)	<.001	.07

Abbreviations: AF, atrial fibrillation; CI, confidence interval; SCD, sudden cardiac death

Cox proportional hazards model adjusted for age, sex, race, and field center

Model 1 additionally adjusted for baseline covariates: heart rate, smoking status, body mass index, hypertension, diabetes, coronary heart disease, heart failure, ECG-based left ventricular hypertrophy, use of beta-blockers, use of digoxin, and use of anti-arrhythmic drugs. In CHS, Model 2 was not adjusted for use of digoxin

Per 1000 person-years of follow-up