Table 3.

Differences in baseline demographic and clinical characteristics in primary prevention patients between the Improve SCA registry and previous large-scale non-Asian-Pacific registries from the 2000s

	MADIT II 2002 [8]	DEFINITE 2004 [9]	COMPANION 2004 [10, 11]	SCD-HeFT 2005 [12]	DANISH 2016 [13]	EU-CERT-ICD 2020 [14]	Improve SCA 2020
N	1232	458	1520	2521	1116	2247	2696
N. of patients with defibrillator	742	229	595	829	556	1516	1399
Median follow-up time (months)	20	29	16	45.5	67.6	28.8 ± 13.2	21.6 ± 10.2
Age (years)	64	58.3	66	60	63	62.4	61
Male (%)	84.4	71.2	67	77	72.6	81.8	76.7
NICM (%)	0	100	45	47	100	35	68.5
Country income level LMI/UMI/HI (%)	0/0/100	0/0/100	0/0/100	0/0/100	0/0/100	0/? /Mainly HI	21.2/50.1/28.7
Ethnicity (%)
Black or African (%)	-	25.8	-	16.9	-	-	0.5
White (%)	87	67.2	Mainly White	76.6	Mainly White	Mainly White	6.9
Asian (%)	-	0.2	-	-	-	-	89.8
Medical history
NYHA Class, I/II/III/IV (%)	36.5/34.6/24.2/4.6	21.6/57.4/21/0	-/-/86/14	-/69/31/-	-/53/45/1	60.5(I/II)/39.5(III/IV)	1.2/47/51.7/0
Hypertension (%)	53	-	-	55.6	31.2	-	38.7
Diabetes (%)	34.98	22.9	41	30.4	19	30.3	30.5
Myocardial infarction (%)	100	0	-	45	0	-	35.1
CRT implanted (%)	0	0	79.7	0	58	0	25.5
NSVT (%)	-	90.6	-	23.1	-	-	29.7
LVEF mean (%)	23.2	21.4	21.2	25	25	28	27
QRS duration (ms)	120	115.1	160	112	146	105.4 ± 17.7	118
LBBB(%)	18.6	19.7	70.8	-	53.6	-	24.1
Medicine
Beta blockers (%)	62	84.9	68	69	92	94.3	75.7
ACEI/ARB (%)	89	96.7	90	94	97	91.2	71.2
Diuretics (%)	75.6	86.7	> 94	82	-	72.2	84

Abbreviations: NICM non-ischaemic cardiomyopathy, LMI lower middle income, UMI upper middle income, HI high income, ICD implantable cardioverter-defibrillator, CRT cardiac resynchronization therapy, NYHA New York Heart Association, NSVT non-sustained ventricular tachycardia, LVEF left ventricular ejection fraction, LBBB left Buddle Branch Block, ACEI/ARB angiotensin-converting enzyme inhibitor/angiotensin receptor blocker