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

Table 6 Risk factors for sudden cardiac death in patients with hypertrophic cardiomyopathy

Risk factor studied	Relative risk of SCD	P value	Absolute SCD risk in cohort	Study size	Year	Country
Age
O’Mahony et al[60]	HR 0.99 (0.98-1.00) (Age 42 ± 15)	0.007	5% at 5 years	3675	2014	Europe
Syncope
Liu et al[61]	HR 2.31 (1.22-4.38)			12146	2017	USA, China
O’Mahony et al[60]	HR 2.33 (1.69-3.19)	< 0.001	5% at 5 years	3675	2014	Europe
Christiaans et al[62]	HR 2.68 (0.97–4.38)			9357	2010	Netherlands, UK
Family history of SCD
Christiaans et al[62]	HR 1.27 (1.16–1.38)			9357	2010	Netherlands, UK
O’Mahony et al[60]	HR 1.76 (1.32-2.24)	<0.001	5% at 5 years	3675	2014	Europe
Liu et al[61]	HR 2.34 (1.46- 3.75)			12146	2017	USA, China
Abnormal blood pressure response during exercise
Liu et al[61]	HR 1.38 (0.65-2.89) (BP dropping on excersice)			12146	2017	USA, China
Christiaans et al[62]	HR 1.30 (0.64–1.96) (BP dropping on excersice)			9357	2010	Netherlands, UK
Non sustained ventricular tachycardia
Liu et al[61]	HR 2.92 (1.97-4.33)			12146	2017	USA, China
Sugrue et al[63]	HR 3.36 (1.00-11.35)	0.05		52	2017	USA
O’Mahony et al[60]	HR 2.53 (1.85-3.47)	< 0.001	5% at 5 years	3675	2014	Europe
Christiaans et al[62]	HR 2.89 (2.21–3.58)			9357	2010	Netherlands, UK
Left ventricular wall thickness/hypertrophy
Liu et al[61]	HR 3.17 (1.64-6.12) (Maximum LV wall thickness ≥  30 mm)			12146	2017	USA, China
Maeda et al[64]	HR 1.21 (1.04–1.39) (Maximum left ventricular wall thickness per 1-mm increase)	0.011		593	2016	Japan
O’Mahony et al[60]	HR 1.05 (1.03-1.07) (Maximal LV wall thickness in mm 21.5 ± 6)	< 0.001	5% at 5 years	3675	2014	Europe
Christiaans et al[62]	HR 3.10 (1.81–4.40) (LVH ≥ 20 mm)			9357	2010	Netherlands, UK
Left ventricular outflow tract obstruction
Liu et al[61]	HR 2.41 (1.55-3.73)			12146	2017	USA, China
O’Mahony et al[60]	HR 1.01 (1.00-1.01) [LVOT Gradient mmHG 18 (6-58)]	0.005	5% at 5 years	3675	2014	Europe
Left atrial diameter
O’Mahony et al[60]	HR 1.04 (1.02-1.05) (LA diameter in mm 46.2 ± 9)	< 0.001	5% at 5 years	3675	2014	Europe

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