Table 2.
Subgroup analyses of HIF-1α expression with OS in tissue samples.
| Variables | HR with 95% CI | Heterogeneity (p) | p value | Studies | Cases | TSA |
|---|---|---|---|---|---|---|
| Study region | ||||||
| Asian | 2.14 (1.40–3.28) | 0.036 | <0.001 | 5 | 461 | More studies |
| European | 1.39 (1.13–1.71) | <0.001 | 0.002 | 12 | 1566 | More studies |
| Tumor location | ||||||
| Metastatic colorectal cancer | 1.70 (0.50–5.84) | 0.021 | 0.398 | 3 | 423 | More studies |
| Advanced cervical cancer | 1.40 (0.91–2.13) | 0.273 | 0.122 | 2 | 227 | More studies |
| Others | 1.71 (1.30–2.24) | <0.001 | <0.001 | 12 | 1377 | More studies per cancer type |
| Histologic subtype | ||||||
| Squamous cell carcinoma | 1.38 (0.87–2.17) | 0.214 | 0.171 | 4 | 375 | More studies |
| Others | 1.67 (1.29–2.16) | <0.001 | <0.001 | 13 | 1652 | No need |
| Survival status | ||||||
| 5 years | 1.36 (1.18–1.57) | 0.264 | <0.001 | 10 | 1566 | No need |
| 3 years | 2.05 (0.96–4.39) | 0.001 | 0.064 | 4 | 204 | More studies |
| <3 years | 3.47 (1.41–8.52) | 0.998 | 0.007 | 2 | 95 | More studies |
| Study design | ||||||
| Randomized controlled trial | 1.29 (0.69–2.40) | NA | 0.422 | 1 | 144 | More studies |
| Prospective | 1.39 (1.14–1.68) | 0.263 | 0.001 | 4 | 734 | More studies |
| Retrospective | 1.79 (1.25–2.56) | <0.001 | 0.001 | 12 | 1149 | More studies |
| Age (years) | ||||||
| >60 | 2.10 (1.40–3.15) | 0.192 | <0.001 | 4 | 285 | More studies |
| ⩽60 | 1.44 (1.21–1.71) | 0.315 | <0.001 | 8 | 1017 | No need |
| Not clear | 1.40 (0.83–2.34) | <0.001 | 0.204 | 5 | 725 | More studies |
| Study quality | ||||||
| ⩾24 | 1.66 (1.24–2.21) | 0.015 | 0.001 | 8 | 1234 | More studies |
| <24 | 1.54 (1.09–2.18) | <0.001 | 0.014 | 9 | 793 | More studies |
| Center design | ||||||
| Multicenter | 1.50 (1.12–2.02) | 0.008 | 0.007 | 7 | 1196 | More studies |
| Single-center | 1.80 (1.10–2.95) | <0.001 | 0.019 | 8 | 609 | More studies |
| Not clear | 1.49 (1.07–2.06) | 0.598 | 0.017 | 2 | 222 | More studies |
| Sample size | ||||||
| >100 | 1.45 (1.06–1.99) | <0.001 | 0.019 | 8 | 1508 | More studies |
| ⩽100 | 1.89 (1.28–2.77) | <0.001 | 0.001 | 9 | 519 | More studies |
| Treatment regimen | ||||||
| Surgery and nonsurgical treatment | 1.40 (1.08–1.82) | <0.001 | 0.012 | 8 | 1209 | More studies |
| Nonsurgical treatment | 1.85 (1.29–2.64) | <0.001 | 0.001 | 9 | 818 | More studies |
Nonsurgical treatment such as chemotherapy, radiotherapy, or chemoradiotherapy etc. was used.
95% CI, 95% confidence interval; HIF-1α, hypoxia inducible factor-1α; HR, hazard ratio; OS, overall survival; TSA, trial sequential analysis.