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

Table 3 Risk factors for sudden cardiac death post myocardial infarction

Risk factor studied	Relative risk of SCD	P value	Absolute SCD risk in cohort	Study size	Year	Country
Age
Rao et al[24]	OR 1.03 (1.00-1.05) (Increasing age)	0.0163	4.9% in the 1st month post MI	929	2012	India
Mehta et al[25]	OR 0.12; Standard error = 0.02 (Age per 1 year increase)	0.0001		2948	2001	North America
Abildstrom et al[26]	OR 1.56 (1.43–1.70) (Age per 10 years)	< 0.0001	5.3% at 1 year	5983	2002	Denmark
Female gender
Rao et al[24]	OR 1.78 (1.02-2.85)	0.0042	4.9% in the 1st month post MI	929	2012	India
Greenland et al[27]	OR 1.72 (1.45-2.04)	< 0.0005		5839	1991	Israel
Greenland et al[27]	OR 1.32 (1.05-1.66) (Death at 1 year)	< 0.03		5839	1991	Israel
Ghaffari et al[28]	OR 1.76 (1.22–2.54) (univariate analysis)	0.002		1017	2017	Iran
Ghaffari et al[28]	OR 1.19 (0.77–1.8) (multivariate analysis)	0.407		1017	2017	Iran
Macintyre et al[29]	OR 1.09 (1.06 to 1.13) (Death at 1 year)	< 0.00001		201114	2001	UK
Male gender
Abildstrom et al[26]	OR 1.34 (1.11–1.63)	< 0.005	5.3% at 1 year	5983	2002	Denmark
LV dysfunction
Rao et al[24]	OR 2.35 (1.09-5.03) (Severe LV dysfunction ≤ 30%)	0.0292	4.9% in the 1st month post MI	929	2012	India
Solomon et al[30]	HR 1.21 (1.10 to 1.30) (LV depression by each 5 percentage points)		7% at 1 month post MI; 11% at 2 years post MI	14609	2005	North America, Europe and New Zealand
Klem et al[31]	HR 6.30 (1.40-28.00) (LVEF > 30% and significant scarring > 5% on CMRI compared to no scarring)	0.02		137	2012	USA
Klem et al[31]	HR 3.90 (1.20-13.10) (LVEF ≤ 30% and those with scar > 5% on CMRI compared to those with scarring)	0.03		137	2012	USA
Yeung et al[32]	HR 3.60 (1.46–8.75) (LVEF ≤ 30%)	< 0.01		610	2012	China
Chitnis et al[33]	OR 4.51 (2.20–9.24) (LVEF ≤ 35%)	< 0.0001	4% in those with EF > 35% at 1 year post MI; 8% in those with EF≤ 35% at 1 year post MI	929	2014	India
Adabag et al[34]	HR 3.64 (1.71-7.75) (presence of heart failure based on the framingham criteria)	< 0.001		693	2008	USA
Right ventricular involvement
Mehta et al[25]	OR 3.20 (2.40-4.10)	< 0.00001		2948	2001	Canada
Diabetes
Yeung et al[32]	HR 1.90 (1.04–3.40)	0.04		610	2012	China
Junttila et al[35]	HR 3.80 (2.40–5.80)	< 0.001		3276	2010	Finland
Ventricular arrythmia
Maggioni et al[36]	RR 2.24 (1.22-4.08) (more than 10 premature ventricular beats per hour)	0.002		8676	1993	Italy
Maggioni et al[36]	RR 1.20 (0.80-1.79) (NSVT)			8676	1993	Italy
Mäkikallio et al[37]	HR 2.40 (1.30–4.40) (Ventricular premature complexes 10/h)	0.0049		2130	2005	Finland
Mäkikallio et al[37]	HR 3.30 (1.70–6.50) (NSVT)	< 0.0005		2130	2005	Finland
ECG features
Mäkikallio et al[37]	HR 3.30 (1.70–6.50) (QRS ≥ 120 ms)	0.0004		2130	2005	Finland
Zimetbaum et al[38]	HR 1.44 (1.11-1.88) (Non-specific intraventricular conduction delay)	0.0069		1638	2004	USA
Zimetbaum et al[38]	HR 1.49 (1.02-2.17) (LBBB)	0.0400		1638	2004	USA
Zimetbaum et al[38]	HR 1.35 (1.08-1.69) (LVH)	0.0082		1638	2004	USA
Siscovick et al[39]	OR 1.40 (1.00-2.00) (LVH)	0.02		688	1996	USA

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