Table 3.

Effects of possible factors in the between-study heterogeneity in the prevalence of KRAF mutations (meta-regression model).

Factors suspected of developing heterogeneity		Coefficient	Standard error	P-value
Year	2011 2014 2015 2016 2017 2018	-0.40 -0.87 -0.18 -0.08 -1.19 -0.60	0.25 0.51 0.28 0.21 0.45 0.29	0.11 0.09 0.53 0.70 0.008* 0.03*
Location	Birjand Kermanshah Shiraz Tabriz Tehran Yazd	0.76 1.30 0.85 0.56 1.17 1.30	0.61 0.51 0.51 0.53 0.47 0.56	0.21 0.01* 0.09 0.30 0.01* 0.02*
Tumor grade	Poorly Moderately Well	-1.29 0.52 0.26	1.74 0.46 0.64	0.46 0.25 0.68
Tumor stage	1 & 2 3 & 4	-0.62 0.68	0.43 0.36	0.14 0.06
Tumor location	Colon Rectum	1.67 -1.67	0.90 0.90	0.07 0.07
Sex (male)		-0.29	1.11	0.79
Mean age		-0.07	0.03	0.01*
Sample size		0.0001	0.0004	0.81