Table 4.

Meta-regression analysis for exploration of the sources of heterogeneity factors.

Factors	Coefficient	Standard error	95% CI	p-value
Region	−1.07	0.98	−2.32, 0.84	0.25
Type of exposure	−0.29	0.82	−2.07, 1.57	0.69
Comparators	0.37	0.91	−1.35, 1.89	0.78