Prognostic significance of pretreatment systemic immune-inflammation index in patients with prostate cancer: a meta-analysis

Table 2 Subgroup analysis of the prognostic role of SII for OS in patients with prostate cancer

Subgroup factors	No. of studies	No. of patients	Effects model	HR (95% CI)	p	Heterogeneity I² (%) Ph
Total	8	1803	Random	2.63 (1.87–3.70)	< 0.001	73.1	< 0.001
Region
Asian	4	553	Random	3.26 (1.36–7.85)	0.008	88.0	< 0.001
Non-Asian	4	1250	Fixed	2.29 (1.88–2.78)	< 0.001	0	0.910
Sample size
< 200	5	633	Random	3.00 (1.52–5.93)	0.002	84.1	< 0.001
≥ 200	3	1170	Fixed	2.29 (1.87–2.81)	< 0.001	0	0.767
Metastatic status
mCRPC	6	1256	Fixed	2.14 (1.80–2.54)	< 0.001	30.8	0.204
Nonmetastatic	2	547	Random	4.87 (1.45–16.29)	0.010	84.5	0.011
Cutoff value
< 600	4	593	Fixed	2.26 (1.75–2.92)	< 0.001	0	0.430
≥ 600	4	1210	Random	2.89 (1.51–5.53)	0.001	87.0	< 0.001
Cutoff selection
ROC curve	3	1044	Fixed	2.55 (1.99–3.26)	< 0.001	0	0.382
Literature	2	259	Fixed	2.18 (1.41–3.37)	< 0.001	0	0.919
Median/mean value	2	270	Random	3.50 (0.58–21.13)	0.172	95.6	< 0.001
X-tile software	1	230	-	2.08 (1.48–2.92)	< 0.001	-	-
Study design
Retrospective	7	1723	Random	2.70 (1.84–3.97)	< 0.001	76.9	< 0.001
Prospective	1	80	-	2.23 (1.20–4.16)	0.012	-	-
Study center
Single center	7	1284	Random	2.72 (1.75–4.24)	< 0.001	76.9	< 0.001
Multicenter	1	519	-	2.40 (1.82–3.16)	< 0.001	-	-
Treatment
Hormone therapy + chemotherapy	4	593	Fixed	2.26 (1.75–2.92)	< 0.001	0	0.430
Radical prostatectomy	2	547	Random	4.87 (1.45–16.29)	0.010	84.5	0.011
Radium-223/chemotherapy	2	663	Random	1.89 (1.13–3.16)	0.015	76.0	0.041
Survival analysis type
Multivariate	6	1493	Random	2.90 (1.78–4.71)	< 0.001	80.1	< 0.001
Univariate	2	310	Fixed	2.11 (1.57–2.85)	< 0.001	0	0.846

OS overall survival, SII systemic immune-inflammation index, ROC receiver operating characteristic, mCRPC metastatic castration-resistant prostate cancer

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