Group | Number of cohorts | HR and 95% CI | P value | Heterogeneity (%) | P value for heterogeneity | Ratio between subgroups | P value between- subgroup |
---|---|---|---|---|---|---|---|
Country | |||||||
 Eastern Countries | 9 | 0.59 (0.37–0.92) | 0.021 | 76.3 | < 0.001 | 0.68 (0.38–1.21) | 0.189 |
 Western Countries | 10 | 0.87 (0.61–1.25) | 0.455 | 81.6 | < 0.001 | ||
Study design | |||||||
 Prospective | 3 | 0.81 (0.18–3.75) | 0.792 | 83.7 | 0.002 | 1.16 (0.25–5.38) | 0.852 |
 Retrospective | 16 | 0.70 (0.55–0.89) | 0.004 | 64.7 | < 0.001 | ||
Disease status | |||||||
 Adenocarcinoma | 6 | 0.65 (0.36–1.18) | 0.154 | 75.5 | 0.001 | 0.86 (0.43–1.72) | 0.660 |
 Both | 13 | 0.76 (0.53–1.10) | 0.152 | 86.7 | < 0.001 | ||
Sample size | |||||||
 500 or more | 2 | 0.52 (0.36–0.76) | 0.001 | 49.4 | 0.160 | 0.68 (0.41–1.10) | 0.117 |
 <  500 | 17 | 0.77 (0.56–1.06) | 0.106 | 81.4 | < 0.001 | ||
Mean age (years) | |||||||
 65.0 or older | 4 | 0.59 (0.36–0.98) | 0.043 | 73.2 | 0.011 | 0.65 (0.35–1.19) | 0.160 |
 <  65.0 | 11 | 0.91 (0.65–1.28) | 0.595 | 78.0 | < 0.001 | ||
Percentage male (%) | |||||||
 50.0 or greater | 12 | 0.81 (0.55–1.19) | 0.290 | 86.2 | < 0.001 | 1.35 (0.82–2.23) | 0.242 |
 <  50.0 | 7 | 0.60 (0.43–0.82) | 0.002 | 42.9 | 0.105 | ||
Percentage of current/past smokers (%) | |||||||
 50.0 or greater | 11 | 0.78 (0.52–1.17) | 0.239 | 87.5 | < 0.001 | 1.50 (0.64–3.50) | 0.349 |
 <  50.0 | 5 | 0.52 (0.25–1.11) | 0.092 | 81.1 | < 0.001 | ||
Percentage of patients using TKI (%) | |||||||
 30.0 or greater | 9 | 0.60 (0.48–0.75) | < 0.001 | 26.2 | 0.211 | 0.59 (0.32–1.10) | 0.099 |
 <  30.0 | 4 | 1.01 (0.57–1.81) | 0.963 | 87.3 | < 0.001 | ||
Study quality | |||||||
 High | 10 | 0.67 (0.50–0.90) | 0.007 | 58.0 | 0.011 | 0.85 (0.47–1.53) | 0.585 |
 Low | 9 | 0.79 (0.47–1.31) | 0.357 | 88.3 | < 0.001 |