Table 2.
Subgroup analyses for associations between tissue VEGF expression and overall survival for patients with nasopharyngeal cancer.
| Sratified variables | HR | 95% CI | Heterogeneity (I2 statistics; %) | No. of included studies | P for interaction |
|---|---|---|---|---|---|
| Total | 2.07 | 1.32–3.25 | 79.1 | 14 | NA |
| STUDY REGION | 0.299 | ||||
| Endemic regions | 1.99 | 1.09–3.62 | 85.0 | 10 | |
| Non-endemic regions | 2.350 | 1.55–3.57 | 0 | 4 | |
| SAMPLE SIZE | < 0.001 | ||||
| ≥100 | 3.23 | 1.58–6.60 | 87.9 | 4 | |
| < 100 | 1.44 | 1.07–1.94 | 0 | 10 | |
| FOLLOW-UP PERIOD (MEAN/MEDIAN) | < 0.001 | ||||
| < 5 years | 1.52 | 1.05–2.19 | 0 | 7 | |
| ≥5 years | 2.74 | 1.20–6.26 | 89.6 | 5 | |
| VEGF EXPRESSION CUT-OFF VALUE | < 0.001 | ||||
| >5–10% | 1.58 | 1.12–2.23 | 4.1 | 6 | |
| >25% | 2.65 | 1.02–6.91 | 89.1 | 4 | |
| Score | 2.04 | 1.35–3.07 | 0 | 4 | |
| VEGF EXPRESSION CRITERIA | < 0.001 | ||||
| High vs. low | 2.19 | 0.77–6.21 | 92.7 | 4 | |
| Positive vs. negative | 1.93 | 1.47–2.54 | 0 | 10 | |
| NOS SCORE | < 0.001 | ||||
| < 7 | 1.43 | 1.05–1.95 | 0 | 6 | |
| ≥7 | 2.85 | 1.62–5.03 | 74.5 | 8 | |
CI, confidence interval; HR, hazard ratio; NOS, Newcastle-Ottawa Scale.