3.3 Heterogeneity and publication bias
Egger’s test showed no evidence of publication bias in the studies
analysed except ABCB1 c.3435C>T polymorphism in the(CC vs CT+TT) and (CC+CT vs TT) model. The distribution of
the genotype in the CBZ responsive group of each study was consistent
with HWE except 2 studies [22, 29] for ABCB1
c.3435C>T and 1 study [7] for EPHX1
c.337T>C and c.416A>G . The
heterogeneity and publication bias of included studies on each gene
polymorphism are presented in Table 2. Considering that significant
heterogeneity was identified in overall studies and the ineligible
studies for HWE, we performed a sensitivity analysis by repetitive
calculation of the combined OR estimate and a heterogeneity test after
removing one study at a time. However, while remove 1 study [22] in
the (CC vs TT) model of ABCB1 c.3435C>T which
is not conformed with HWE, the results of association changed with
significant difference (OR =
1.781 (95% CI: 1.166~2.722), P = 0.008) (Table 4).