Table 5.

Effect of geographic origin of the study on the effect size in maximum likelihood meta-regression

Study-level covariates Geographic Origin of Study	No. of studies (homogeneity p-value)**	Effect size*		Difference in effect size estimates
		Point estimate	95% CI	Difference in point estimates	95% CI
Other Asia	3 (p = 0.237)	0.631	0.173–0.933	1.000	0.321–0.604
Europe	5 (p = 0.027)	0.411	0.127–0.770	0.3091	–0.088–0.707
North America	7 (p = 0.339)	0.517	0.297–0.730	0.1482	–0.273–0.569
Meta-Regression for all areas	Slope: 0.409 (95% CI: –0.167–0.987) p = 0.164; Intercept: –1.373 (95% CI –2.944–0.196) p = 0.086

^*Random effects model

^**Cochran's Q

¹p = 0.139

²p = 0.510

Slope; effect parameter (= regression coefficient β₁), Intercept (= coefficient β₀)