Table 3. Meta-regression analysis between pooled relative risk and co-variates of overall survival.

Co-variates	Coefficient	95% CI	Std. Err.	P-value
Year of publication	0.2546	0.1310, 0.3783	0.0631	<0.001
Sample size	0.1655	0.0296, 0.3015	0.0694	0.017
Country of patients	0.1160	0.0953, 0.1367	0.0106	<0.001

Abbreviations: CI =confidence interval