Table 3. Subgroup analyses on all-cause mortality.

Subgroup	Number of studies	Pooled RR	95% CI	Heterogeneity between studies
Study design
Prospective	7	1.92	1.46–2.53	P=0.186; I2 = 31.7%
Retrospective	5	3.75	1.97–7.17	P=0.186; I2 = 31.7%
Region
European	8	2.16	1.68–2.77	P=0.354; I2= 9.7%
Non-European	4	4.33	1.63–11.45	P<0.001; I2 = 88.5%
Type of troponin
cTnT	7	2.36	1.47–3.77	P=0.031; I2= 54.7%;
cTnI	5	2.79	1.68–4.64	P=0.001; I2= 79.7%
Assay of troponin
Conventional	6	2.13	1.41–3.20	P=0.027; I2 = 60.3%;
High-sensitivity	6	3.00	1.83–4.92	P=0.010; I2 = 64.2%
Excluded CHD/AMI patients
Yes	7	2.74	1.96–3.84	P=0.061; I2 = 48.0%
No	5	2.31	1.21–4.41	P=0.009; I2 = 70.2%
Adjusted renal function
Yes	7	2.25	1.43–3.53	P=0.002; I2 = 69.9%
No	5	2.95	2.05–4.25	P=0.236; I2 = 27.8%
NOS
≥7 stars	6	2.45	1.55–3.89	P=0.005; I2 = 70.5%
<7 stars	6	3.00	1.73–5.21	P=0.050; I2= 54.8%