Risk factors for sudden cardiac death to determine high risk patients in specific patient populations that may benefit from a wearable defibrillator

Table 4 Risk factors for sudden cardiac death in heart failure

Risk factor studies	Relative risk of SCD	P value	Absolute SCD risk in cohort	Study size	Year	Country
Age
Lee et al[40]	OR 1.70 (1.45-1.99) (Age per 10 unit increase)	< 0.001		4031	2003	Canada
Cowie et al[41]	HR 1.26 (1.01 to 1.57) (Age per 10 year increase)	0.04		220	2000	UK
Taylor et al[42]	HR 1.10 CI 1.09–1.10 (Increasing age)			6162	2012	UK
Male gender
Taylor et al[42]	HR 1.50 (1.36–1.66)			6162	2012	UK
Vaartjes et al[43]	HR 1.21 (1.14-1.28) at 28 d; HR 1.26 (1.21-1.31) at 1 year; HR 1.28 (1.24-1.31) at year 5			29053	2010	Netherlands
Comorbidities
Lee et al[40]	OR 1.43 (1.03-1.98) 30-day mortality (Cerebrovascular disease)	0.03		4031	2003	Canada
Lee et al[40]	OR 1.66 (1.22-2.27) (COPD)	0.002		4031	2003	Canada
Lee et al[40]	OR, 3.22 (1.08-9.65) (Cirrhosis)	0.04		4031	2003	Canada
Lee et al[40]	OR 2.54 (1.77-3.65) (Dementia)	< 0.001		4031	2003	Canada
Lee et al[40]	OR 1.86 (1.28-2.70) (Cancer)	0.001		4031	2003	Canada
Yoshihisa et al[44]	HR 3.01 (1.11–8.63) (COPD)	0.038		378	2014	Japan
Fisher et al[45]	RR 1.10 (1.06-1.14) Death at 1 year; RR 1.40 (1.28-1.52) death at 5 years (COPD)			9748	2015	USA
Atrial fibrillation
Taylor et al[44]	HR 1.55 (1.26–1.92)			6162	2012	UK
Ahmed et al[46]	HR 1.41 (1.08-1.83)			944	2005	USA
Corell et al[47]	HR 1.38 (1.07-1.78)	0.01		1019	2007	Denmark
Middlekauff et al[48]	HR 0.89 (0.55-1.23)	0.013		390	1991	USA
Ventricular arrythmia
Doval et al[49]	RR 2.77 (1.78-4.44) (NSVT)	< 0.001	23.7% at 2 years in those with NSVT; 8.8% at 2 years in those without NSVT	516	1996	Argentina
Doval et al[49]	RR 3.37 (1.57-7.25) (Couplets)	< 0.0005	23.7% at 2 years in those with NSVT; 8.8% at 2 years in those without NSVT	516	1996	Argentina
Teerlink et al[50]	RR 1.16 (1.09–1.24) (NSVT)	0.001	13% at 2 years	1080	2000	USA
Szabó et al[51]	RR 3.50 (1.54-7.98) (VT)	0.003		211	1994	Netherlands
Szabó et al[51]	RR 2.68 (1.11-6.48) (Freq. VT > 144 beats/min)	0.029		211	1994	Netherlands
Szabó et al[51]	RR 3.89 (1.61-9.43) (Length VT > 2s)	0.003		211	1994	Netherlands
Echocardiographic variables
Taylor et al[42]	HR 1.80 (1.55–2.10) (EF < 40% vs > 50%)			6162	2012	UK
Taylor et al[42]	HR 1.29 (1.11–1.50) (EF 40%–50% vs > 50%)			6162	2012	UK
Shadman et al[52]	OR 1.15 (EF per 10% decrease)	0.005		9885	2015	USA
Quiñones et al[53]	RR 2.75 (1.62-4.66) (1-SD difference in LV Mass)	0.0002		1209	2000	USA
Quiñones et al[53]	RR 1.84 (1.08-3.15) (1-SD difference in LA Diameter)	0.03		1209	2000	USA
Quiñones et al[53]	RR 2.73 (1.43-5.20) (1-SD difference in lv end systolic dimension)	0.003		1209	2000	USA
Grayburn et al[54]	HR 1.01 (1.00–1.01) (LV end-diastolic volume index)	0.0012		336	2005	USA
Deranged kidney function
Grayburn et al[54]	HR 2.023 (1.24–3.32)	0.0052		336	2005	USA
Cowie et al[41]	HR 2.64 (1.87-3.74)	< 0.001		220	2000	UK

SCD: Sudden cardiac death; HR: Hazard ratio; OR: Odds ratio; LV: Left ventricular; EF: Ejection fraction.