Table 2.

Subgroup analysis on all-cause mortality

Subgroup	Number of studies	Pooled RR	95% CI	Heterogeneity between studies
Type of patients
All CAD	4	1.84	1.16 to 2.93	p=0.026; I2=67.7%
STEMI	2	1.82	1.10 to 3.03	p=0.209; I2=36.6%
Follow-up duration
>24 months	4	1.51	1.16 to 1.96	p=0.146; I2=44.3%
≤24 months	2	2.75	1.68 to 4.51	p=0.887; I2=0.0%
Sample sizes
≥800	4	1.77	1.12 to 2.79	p=0.067; I2=58.2%
<800	2	1.93	1.16 to 3.20	p=0.107; I2=61.5%
Country
China	3	1.44	1.14 to 1.82	p=0.187; I2=40.3%
Others	3	2.85	1.80 to 4.50	p=0.928; I2=0.0%
Study quality
NOS ≥7	4	1.51	1.16 to 1.96	p=0.146; I2=44.3%
NOS <7	2	2.75	1.68 to 4.51	p=0.887; I2=0.0%

CAD, coronary artery disease; NOS, Newcastle–Ottawa Scale; RR, risk ratio; STEMI, ST-segment elevation myocardial infarction.