Prognostic role of the systemic immune-inflammation index in biliary tract cancers: a meta-analysis of 3,515 patients

Table 2 Subgroup analysis of the prognostic effect of SII for OS in patients with BTC

Subgroups	No. of studies	No. of patients	HR (95%CI)	p	Effects model	Heterogeneity
Subgroups	No. of studies	No. of patients	HR (95%CI)	p	Effects model	I²(%)	Ph
Total	13	3515	1.77 (1.47–2.14)	<0.001	Random	56.2	0.007
Countries
Asian	10	2,464	1.97 (1.54–2.54)	<0.001	Random	54.3	0.020
Non-Asian	3	1,051	1.47 (1.14–1.90)	0.003	Random	50.9	0.130
Sample size
≤140	7	693	2.31 (1.59–3.36)	<0.001	Random	63.7	0.011
>140	6	2,822	1.55 (1.25–1.93)	<0.001	Random	52.4	0.062
Histology
BTC	2	218	1.97 (0.42–9.30)	0.394	Random	90.3	0.001
ECC	3	485	1.49 (1.08–2.05)	0.014	Fixed	23.9	0.269
ICC	5	1,505	1.65 (1.42–1.92)	<0.001	Fixed	36.5	0.178
GBC	3	1,307	2.00 (1.58–2.51)	<0.001	Fixed	48.2	0.145
TNM stage
I–III	6	2,651	1.96 (1.67–2.30)	<0.001	Fixed	0	0.483
I–IV	4	618	1.42 (1.19–1.69)	<0.001	Fixed	0	0.524
IV	3	246	2.33 (0.72–7.57)	0.160	Random	84.5	0.002
Treatment
Surgery	10	3,184	1.70 (1.51–1.92)	<0.001	Fixed	41.8	0.079
Non-surgery	3	331	1.81 (0.82–4.04)	0.144	Random	82.0	0.004
Cutoff value
≤600	7	2,275	1.59 (1.35–1.87)	<0.001	Fixed	47.8	0.074
>600	6	1,240	2.17 (1.55–3.03)	<0.001	Random	67.1	0.009
Survival analysis
Multivariate	9	2,979	1.81 (1.57–2.09)	<0.001	Fixed	47.8	0.053
Univariate	4	536	1.64 (1.10–2.45)	0.016	Random	65.5	0.034

BTC Biliary tract cancer, ECC Extrahepatic cholangiocarcinoma, ICC Intrahepatic cholangiocarcinoma, GBC Gallbladder cancer, OS Overall survival

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