Table 3.

Sensitivity analysis

First author	Index	Before exclusion	After exclusion	Statistical significance
Gao [15]	CR	RR = 1.49, 95 % CI = 1.33–1.67, Z = 6.83, P < 0.00001	RR = 1.56, 95 % CI = 1.38–1.77, Z = 7.07, P < 0.00001	No difference
Zhao [14]	RR	RR = 5.38, 95 % CI = 2.81–10.31, Z = 5.08, P < 0.00001	RR = 5.21, 95 % CI = 2.67–10.16, Z = 4.85, P < 0.00001	No difference