Table 2. Pooled hazard ratios (HRs) for OS according to subgroup analyses.

Subgroup	No. of studies	No. of patients	Effects model	HR (95% CI)	P value	Heterogeneity
						I2 (%)	Ph
Overall	8	1,904	Random	1.22 (1.04–1.43)	0.02	70	0.001
Region
Asia	6	1,670	Random	1.25 (1.03–1.52)	0.02	53	0.06
Europe	2	234	Random	1.21 (0.78–1.87)	0.40	80.8	0.02
Treatment
Surgery	4	823	Random	1.24 (0.95–1.62)	0.11	73.2	0.01
Chemotherapy	2	517	Random	1.26 (0.86–1.84)	0.24	68	0.08
Mixed	2	564	Random	1.25 (0.84–1.85)	0.28	68.9	0.07
Disease stage
No-metastatic	2	260	Random	1.23 (0.75–2.02)	0.42	77.8	0.03
Mixed (non-metastatic & metastatic)	3	1,003	Random	1.19 (0.89–1.60)	0.24	58.7	0.09
Metastatic	3	641	Random	1.34 (1.01–1.77)	0.04	53.4	0.12
Cut-off for PLR
>150	2	308	Fixed	1.73 (1.21–2.49)	0.003	36	0.21
≤150	6	1,596	Random	1.13 (0.99–1.30)	0.08	60	0.03
NOS score
<7	3	444	Random	1.50 (0.85–2.64)	0.16	79	0.008
≥7	5	1460	Fixed	1.18 (1.04–1.33)	0.008	40	0.16