Table 3.
Subgroup analysis of OS by pathological types, publication year, NOS score, and country.
| Subgroup | No. of studies | No. of patients | P value | Pooled HR (95% CI) | PHet | I2 (%) |
|---|---|---|---|---|---|---|
| Pathological types | ||||||
| Adenocarcinoma | 5 | 613 | ≤0.001 | 1.68 (1.34-2.11) | 0.375 | 5.6% |
| Squamous cell carcinoma | 2 | 105 | 0.270 | 1.97 (0.59-6.55) | 0.009 | 85.4% |
| Small cell carcinoma | 1 | 50 | 0.402 | 1.74 (0.70-2.23) | ||
| Publication year | ||||||
| 2010-2016 | 8 | 1150 | ≤0.001 | 1.56 (1.33-1.83) | 0.819 | 0.0% |
| 2017 | 2 | 222 | ≤0.001 | 2.94 (2.22-3.88) | 0.896 | 0.0% |
| NOS score | ||||||
| <7 | 4 | 374 | 0.004 | 1.46 (1.12-1.89) | 0.432 | 0.0% |
| ≥7 | 6 | 998 | ≤0.001 | 2.01 (1.55-2.60) | 0.038 | 57.6% |
| Country | ||||||
| China | 6 | 874 | ≤0.001 | 1.57 (1.32-1.87) | 0.671 | 0.0% |
| Other | 4 | 498 | ≤0.001 | 2.20 (1.52-3.19) | 0.051 | 61.5% |
OS, overall survival; NO, number of sample size; HR, hazard ratio; CI, confidence interval; NOS, Newcastle-Ottawa-Scale.