Table 2 Stratified analyses of the pooled HRs of overall survival by tumor type, sample size, follow-up months, and survival analysis method
Subgroup analysis | No. of studies | No. of patients | Pooled HR (95% CI) | Heterogeneity | ||
|---|---|---|---|---|---|---|
Fixed model | p-value | I2 (%) | p-value | |||
Tumor type | ||||||
 Digestive system | 6 | 374 | 2.00 (1.73, 2.31) | 0.000 | 0.0 | 0.989 |
 Others | 4 | 316 | 2.31 (1.84, 2.89) | 0.000 | 0.0 | 0.573 |
Sample size | ||||||
 ≥60 | 6 | 505 | 2.09 (1.84, 2.37) | 0.000 | 0.0 | 0.932 |
 < 60 | 4 | 185 | 1.97 (1.16, 3.34) | 0.012 | 0.0 | 0.681 |
Follow-up months | ||||||
 ≥60 | 7 | 530 | 2.09 (1.84, 2.37) | 0.000 | 0.0 | 0.793 |
 < 60 | 3 | 160 | 2.02 (1.19, 3.46) | 0.01 | 0.0 | 0.766 |
Survival analysis method | ||||||
 Multivariate | 3 | 223 | 2.07 (1.78, 2.40) | 0.000 | 30.6 | 0.237 |
 Univariate | 7 | 467 | 2.12 (1.71, 2.63) | 0.000 | 0.0 | 0.993 |