Table 2. Subgroup analyses of OS and DFS based on different factors.
| Survival outcome | Subgroup | Studies, n | Effects model | HR (95%CI) | p value | Heterogeneity | Meta-regression, p value | |
| I2(%) | p value | |||||||
| OS | Total | 15 | Fixed | 1.79 (1.55-2.07) | <0.001 | 25.9 | 0.167 | |
| Tumor type | 0.820 | |||||||
| eCCA | 7 | Random | 1.73 (1.08-2.75) | 0.022 | 62.7 | 0.013 | ||
| iCCA | 4 | Fixed | 1.79 (1.42-2.25) | <0.001 | 0 | 0.718 | ||
| iCCA+eCCA | 3 | Fixed | 1.82 (1.38-2.40) | <0.001 | 0 | 0.508 | ||
| GBC | 1 | - | 1.92 (0.95-3.88) | 0.069 | - | - | ||
| Ethnicity | 0.783 | |||||||
| Asian | 11 | Fixed | 1.77 (1.51-2.07) | <0.001 | 43.5 | 0.06 | ||
| Caucasian | 4 | Fixed | 1.89 (1.34-2.67) | <0.001 | 0 | 0.787 | ||
| Sample size | 0.960 | |||||||
| <100 | 8 | Fixed | 1.80 (1.38-2.35) | <0.001 | 42 | 0.099 | ||
| ≥100 | 7 | Fixed | 1.78 (1.50-2.12) | <0.001 | 12 | 0.338 | ||
| Cut-off value | 0.166 | |||||||
| Cut-off value 5% | 5 | Fixed | 1.80 (1.45-2.24) | <0.001 | 0 | 0.847 | ||
| Cut-off value 1% | 4 | Fixed | 1.49 (1.12-1.98) | 0.001 | 0 | 0.917 | ||
| Other cut-off values | 6 | Random | 1.88 (1.14-3.10) | 0.014 | 65.0 | 0.014 | ||
| DFS | Total | 6 | Random | 1.38 (1.00-1.91) | 0.051 | 64 | 0.016 | |
| Tumor type | 0.271 | |||||||
| eCCA | 3 | Random | 0.97 (0.53-1.78) | 0.930 | 76 | 0.015 | ||
| GBC | 1 | - | 1.87 (0.95-3.68) | 0.070 | - | - | ||
| iCCA | 2 | Fixed | 1.76 (1.28-2.42) | <0.001 | 0 | 0.752 | ||
| Ethnicity | 0.365 | |||||||
| Asian | 5 | Random | 1.42 (0.93-2.18) | 0.108 | 63.6 | 0.027 | ||
| Caucasian | 1 | - | 1.18 (0.95-1.47) | 0.139 | - | - | ||
| Sample size | 0.288 | |||||||
| <100 | 3 | Random | 0.93 (0.40-2.16) | 0.869 | 78.8 | 0.009 | ||
| ≥100 | 3 | Fixed | 1.64 (1.27-2.13) | <0.001 | 0 | 0.724 | ||
| Cut-off value | 0.425 | |||||||
| Cut-off value 5% | 3 | Fixed | 1.78 (1.33-2.37) | <0.001 | 0 | 0.939 | ||
| Cut-off value 1% | 2 | Fixed | 1.22 (1.00-1.49) | 0.045 | 0 | 0.458 | ||
| Other cut-off values | 1 | - | 0.16 (0.04-0.65) | 0.011 | - | - | ||
iCCA, intrahepatic cholangiocarcinoma; eCCA, extrahepatic cholangiocarcinoma; GBC, gallbladder cancer; OS, overall survival; DFS, disease-free survival.