Table 3.

Results of subgroup analysis of pooled hazard ratios of OS of patients.

Stratified analysis	No. of studies	Pooled HR (95% CI)	P‐value	Heterogeneity
				I2 (%)	PQ
Study type
Prospective	8	2.44 (1.70–3.51)	<0.001	32	0.17
Retrospective	20	1.70 (1.47–1.96)	<0.001	21	0.19
Treatment
Surgery	9	2.06 (1.43–2.96)	<0.001	31	0.17
Non surgery	18	1.91 (1.57–2.32)	<0.001	44	0.02
Cut-off value
<1 ng/ml	14	2.17 (1.62–6.89)	<0.001	45	0.05
1–5 ng/ml	6	2.12 (1.42–3.17)	<0.001	44	0.11
>5ng/ml	6	1.53 (1.17–1.99)	0.002	21	0.28
Analysis
Multivariate	22	1.83 (1.55–2.18)	<0.001	30	0.10
Univariate	6	2.07 (1.40–3.04)	<0.001	45	0.09
Immunotherapy
No	25	1.95 (1.63–2.34)	<0.001	30	0.09
Yes	3	1.51 (1.14–1.99)	0.004	44	0.22
Detection of sPD-L1
Pre-treatment	21	1.90 (1.56–2.32)	<0.001	38	0.04
On-treatment	3	2.19 (1.35–3.56)	0.002	22	0.28
Post-treatment	1	6.51 (1.60–26.55)	0.009	–	–

CI, confidence interval; HR, hazard ratio; OS, overall survival.