Table 3.

Subgroup analyses of the associations between NLR and survival.

Subgroup	No. of studies	Test of association			Test of heterogeneity
		HR	95% CI	P-value	I2(%)	P-value
Progression-free survival
Total	12	1.44	1.26–1.65	<0.001	88.7	<0.001
Publication year
2017	6	1.20	1.06–1.37	0.004	90.5	<0.001
2018	3	1.59	1.25–2.02	<0.001	0.0	0.714
2019	3	3.05	2.01–4.62	<0.001	0.0	0.377
Region
Asia	4	1.55	1.00–2.39	0.051	83.3	<0.001
Europe and America	8	1.98	1.38–2.84	<0.001	86.3	<0.001
Sample size
>100	7	1.22	1.09–1.38	0.001	88.9	<0.001
≤100	5	2.17	1.01–4.55	<0.001	48.9	0.098
NLR cut-off
>3	3	1.48	0.93–2.37	0.098	73.1	0.024
>4	3	1.73	1.24–2.41	0.001	29.9	0.240
>5	6	2.09	1.28–3.40	0.003	90.9	<0.001
Follow-up period (months)
>12	1	1.46	1.06–2.01	0.019	–	–
≤12	6	1.68	1.13–2.50	0.010	82.3	<0.001
NR	5	2.24	1.30–3.86	0.004	90.3	<0.001
Quality score
7	5	2.54	1.68–3.83	<0.001	48.9	0.098
8	7	1.22	1.09–1.38	0.001	88.9	<0.001
Overall survival
Total	13	2.86	2.11–3.87	<0.001	55.4	0.008
Publication year
2017	3	3.25	1.77–5.97	<0.001	55.2	0.107
2018	4	2.57	1.82–3.64	<0.001	0.0	0.718
2019	5	3.02	1.30–7.01	0.001	78.7	0.001
2020	1	2.05	1.25–3.37	0.005	–	–
Region
Asia	3	4.05	2.25–7.31	<0.001	0.0	0.898
Europe and America	10	2.67	1.88–3.79	<0.001	63.5	0.003
Sample
>100	4	2.83	1.62–4.93	<0.001	75.4	0.007
≤100	9	2.90	1.98–4.24	<0.001	44.5	0.071
NLR cut-off
>3	2	2.83	1.37–5.87	0.005	32.3	0.224
>4	2	2.66	1.57–4.50	<0.001	0.0	0.395
>5	9	2.90	1.91–4.39	<0.001	67.6	0.002
Follow-up period (months)
>12	1	3.00	1.58–5.71	0.001	–	–
≤12	6	2.72	1.96–3.76	<0.001	0.0	0.728
NR	6	3.25	1.77–5.97	0.001	55.2	0.107
Quality score
7	9	2.90	1.98–4.24	<0.001	44.5	0.071
8	4	2.83	1.62–4.93	<0.001	75.4	0.007

NR, not reported; HR, hazard ratio; NLR, neutrophil-tof-lymphocyte ratio.