Table 2. Mata-regression of potential heterogeneity within the included studies.

Covariates	Number of studies	Coefficient	SE	RDOR (95% CI)	p -value
Method
Cell blocks	15	0.094	1.4303	1.10(0.05;23.16)	0.9486
Smeard	3
Sample size
≥100	4	1.813	1.0773	6.13(0.62–60.93)	0.1130
<100	14
Geographical location
America	9	0.118	0.54	1.12(0.36–3.56)	0.8306
Europe	3
Asia	6
QUADAS scores
≥10	10	−1.962	0.9976	0.14(0.02–1.18)	0.0679
<10	8

SE, Standard error.