Prognostic and Clinical Value of the Systemic Immune-Inflammation Index in Biliary Tract Cancer: A Meta-Analysis

Table 2

Subgroup analyses for OS and RFS based on different factors.

Subgroup analysis	No. of studies	No. of patients	Effects model	HR (95% CI)	value	Heterogeneity
						(%)	value
OS
Histology
GBC	3	926	Fixed	2.00 (1.58-2.52)	<0.001	48.2	0.145
iCCA	4	1109	Random	1.52 (0.95-2.44)	<0.001	70.4	0.018
eCCA	2	253	Fixed	1.95 (1.26-3.02)	0.03	0.0	0.849
Sample size
≥140	6	2006	Fixed	1.89 (1.62-2.21)	<0.001	0.0	0.610
<140	5	502	Random	1.49 (0.78-2.84)	0.222	87.1	<0.001
Treatment
Surgery	7	2087	Fixed	1.90 (1.62-2.22)	<0.001	0.0	0.499
Cut-off value
≥555	5	1104	Fixed	1.96 (1.57-2.43)	<0.001	21.1	0.280
<555	5	1404	Random	1.74 (1.20-2.53)	0.04	68.9	0.012
Cut-off selection method
ROC curve	7	1535	Random	1.94 (1.39-2.72)	<0.001	66.0	0.07
Country			—
China	8	1680	Random	1.96 (1.48-2.58)	<0.001	59.5	0.16
Total	10	2508	Random	1.92 (1.66-2.21)	<0.001	49.9	0.035

CI: confidence interval; HR: hazard ratio; OS: overall survival; DFS: disease-free survival; ROC: receiver operating characteristics curve; SII: systemic immune-inflammation index; PTBS: percutaneous transhepatic biliary stenting; TACE: transcatheter arterial chemoembolization; K–M curve: Kaplan–Meier curve; GBC: gallbladder cancer; iCCA: intrahepatic cholangiocarcinoma; eCCA: extrahepatic cholangiocarcinoma; cHCC-CCA: combined hepatocellular-cholangiocarcinoma.