Table 2.
Subgroup analysis and meta-regression of the studies regarding overall survival
| Subgroups | Studies | Patients | Pooled HR and 95% CI | P-value | Heterogeneity (I2) | Meta-regression P-value |
|---|---|---|---|---|---|---|
| Ethnicity | 0.748 | |||||
| Caucasian | 18 | 3,827 | 2.08 (1.54–2.81) | <0.001 | 76.3% | |
| Asian | 22 | 2,598 | 1.96 (1.73–2.22) | <0.001 | 9.6% | |
| No of patients | 0.659 | |||||
| >100 | 20 | 4,850 | 2.08 (1.71–2.53) | <0.001 | 62.3% | |
| <100 | 20 | 1,575 | 2.11 (1.66–2.67) | <0.001 | 57.6% | |
| Cutoff | 0.421 | |||||
| Positive vs negative | 13 | 2,562 | 2.50 (1.96–3.19) | <0.001 | 53.9% | |
| >10% of cells stained | 11 | 1,201 | 1.95 (1.50–2.53) | <0.001 | 29.7% | |
| >25% of cells stained | 2 | 188 | 1.63 (1.06–2.52) | 0.027 | 46.5% | |
| Others | 14 | 2,474 | 1.87 (1.42–2.46) | <0.001 | 65.6% | |
| Cancer stage | 0.017 | |||||
| Nonmetastatic | 14 | 2,918 | 2.01 (1.77–2.29) | <0.001 | 23.4% | |
| Mixed (metastatic and nonmetastatic) | 26 | 3,507 | 1.77 (1.58–1.97) | <0.001 | 16.8% | |
| HR obtain method | 0.326 | |||||
| Reported | 34 | 5,881 | 2.14 (1.84–2.50) | <0.001 | 55.5% | |
| Extracted | 6 | 544 | 1.70 (1.03–2.82) | 0.040 | 76.2% | |
| Analysis | 0.319 | |||||
| Univariable analysis | 9 | 768 | 1.76 (1.09–2.85) | 0.020 | 74.7% | |
| Multivariable analysis | 31 | 5,657 | 2.14 (1.84–2.48) | <0.001 | 52.9% |
Abbreviations: CI, confidence interval; HR, hazard ratio.