Table 1.

Subgroup analysis.

Region	Number of included studies	Sample size	Heterogeneity		Effect of the model	Meta-analysis results
			P values	I2		R% (95% CI)	P values
China	21	665	0	78.80%	random	12.9% (8–17.7%)	0
Outside China	17	2363	0	86.70%	random	21.1% (16.5–25.7%)	0
Wuhan	3	199	0	94.50%	random	41.3% (3.2–79.4%)	0.034
Outside Wuhan, China	18	466	0.023	44.40%	random	7.1% (4–10.3%)	0
Total	38	3028	0	87.80%	random	17.7% (13.9–21.5%)	0

CI confidence interval.