Update on the association of hepatitis B with intrahepatic cholangiocarcinoma: Is there new evidence?

Table 2 Summary of meta-analyses evaluating hepatitis B virus infection as a risk factor for intrahepatic cholangiocarcinoma

Ref.	Number of included studies	Data collection period	Regions	Cases	Controls	Pooled OR (95%CI) for HBV infection	Heterogeneity	Publication bias
Clements et al[3], 2020	Case-control = 18	1991-2014	Eastern = 12. Western = 6	14825	681181	4.57 (3.43-6.09)	I2 = 83% Q = 100.88 (P < 0.001)	Funnel plot: Symmetrical. No bias
Tan et al[38], 2020	Case-control = 6	1998-2013	Eastern = 6	3623	13597	5.98 (4.08-8.76)	I2 = 69% Q = 16.01 (P = 0.07)	Funnel plot: Relatively symmetrical. Moderate bias
Zhang et al[39], 2016	Case-control = 11	1991-2013	Eastern = 11	4966	17752	3.18 (2.35-4.30)	I2 = 84% Q: P < 0.001	Begg's test: P = 0.75, Egger's test: P = 0.42. No bias
Li et al[40], 2012	Case-control = 11. Cohort = 2	1991-2008	Eastern = 10. Western = 3	2402. NA	96266. NA	3.42 (2.46-4.74)	I2 = 75% Q = 48.37 (P < 0.001)	Funnel plot: Symmetrical Begg's test: P = 0.70, Egger's test: P = 0.26. No bias
Palmer et al[41], 2012	Case-control = 8	1991-2008	Eastern = 5. Western = 3	2753	291756	5.54 (3.19-9.63)	I2 = 86.3% Q = 51.2 (P < 0.001)	Funnel plot: Symmetrical. No bias
Zhou et al[42], 2012	Case-control = 12. Cohort: = 2	1987-2009	Eastern = 11. Western = 3	2362. NA	96452. NA	3.17 (1.88-5.34)	I2 = 81% Q: P < 0.001	Funnel plot: Asymmetry. Moderate bias

Statistical heterogeneity was assessed by the Cochran’s Q statistic and I² statistic. Significant heterogeneity is considered if Q: P < 0.10 or I² > 60%. Publication bias was evaluated using the Begg’s funnel plot and Egger’s test with P < 0.10 as an indication of publication bias. CI: Confidence interval; HBV: Hepatitis B virus; ICC: Intrahepatic cholangiocarcinoma; NA: Not applicable; OR: Odds ratio.