Table 2.
Summary of subgroup analysis.
| Variable | Subgroup | Treatment | Trial (N) | HR (95% CI) | P-value for HR | Bon | I2 | P-value (Egger’) |
|---|---|---|---|---|---|---|---|---|
| OS analysis (methylated vs. unmethylated) | ||||||||
| Overall | TMZ-containing | 52 | 0.46 (0.41–0.52) | <0.001 | 0.017 | 70.9% | 0.001 | |
| TMZ-free | 12 | 0.97 (0.91–1.03) | 0.32 | 1 | 2.90% | 0.053 | ||
| Race | Caucasian | TMZ-containing | 34 | 0.46 (0.39–0.55) | <0.001 | 0.017 | 75.5% | 0.003 |
| TMZ-free | 8 | 0.99 (0.94–1.04) | 0.71 | 1 | 0% | 0.27 | ||
| Asian | TMZ-containing | 10 | 0.48 (0.42–0.54) | <0.001 | 0.017 | 43.8% | 0.26 | |
| TMZ-free | 4 | 0.78 (0.64–0.95) | 0.015 | 0.24 | 0% | NA | ||
| Mixed race | TMZ-containing | 8 | 0.48 (0.38–0.62) | <0.001 | 0.017 | 67.7% | 0.302 | |
| TMZ- free | 0 | NA | NA | NA | NA | NA | ||
| Study type | non-RCT | TMZ-containing | 48 | 0.46 (0.40–0.52) | <0.001 | 0.017 | 72.9% | 0.001 |
| TMZ-free | 9 | 0.90 (0.78–1.03) | 0.13 | 1 | 26.3% | 0.033 | ||
| RCT | TMZ-containing | 4 | 0.56 (0.48–0.65) | <0.001 | 0.017 | 0% | NA | |
| TMZ-free | 3 | 1.02 (0.83–1.25) | 0.83 | 1 | 0% | NA | ||
| GBM Type | Newly diagnosed | TMZ-containing | 47 | 0.45 (0.40–0.52) | <0.001 | 0.017 | 69.80% | 0.007 |
| TMZ-free | 7 | 0.97 (0.90–1.04) | 0.374 | 1 | 5.6% | NA | ||
| Elderly | TMZ-containing | 8 | 0.46 (0.32–0.65) | <0.001 | 0.017 | 71% | 0.695 | |
| TMZ-free | 3 | 1.02 (0.83–1.25) | 0.83 | 1 | 0% | NA | ||
| Recurrent | TMZ-containing | 5 | 0.59 (0.44–0.78) | <0.001 | 0.017 | 65% | NA | |
| TMZ-free | 5 | 0.92 (0.70–1.19) | 0.52 | 1 | 16.40% | NA | ||
| PFS analysis (methylated vs. un-methylated) | ||||||||
| Overall | TMZ-containing | 22 | 0.48 (0.40–0.57) | <0.001 | 0.014 | 67.4% | 0.092 | |
| TMZ-free | 3 | 0.76 (0.57–1.02) | 0.068 | 0.748 | 40.8% | NA | ||
| Race | Caucasian | TMZ-containing | 14 | 0.46 (0.34–0.63) | <0.001 | 0.014 | 76.2% | 0.22 |
| TMZ-free | 2 | 0.75 (0.41–1.38) | 0.35 | 1 | 54.8% | NA | ||
| Asian | TMZ-containing | 5 | 0.49 (0.41–0.59) | <0.001 | 0.014 | 0% | NA | |
| TMZ-free | 1 | 0.69 (0.50–0.94) | 0.02 | 0.24 | NA | NA | ||
| Mixed race | TMZ-containing | 3 | 0.51 (0.40–0.65) | <0.001 | 0.014 | NA | NA | |
| TMZ-free | 0 | NA | NA | NA | NA | NA | ||
| Study type | non-RCT | TMZ-containing | 21 | 0.47 (0.39–0.56) | <0.001 | 0.014 | 67% | 0.19 |
| TMZ-free | 3 | 0.76 (0.57–1.02) | 0.07 | 0.7 | 40.8% | NA | ||
| RCT | TMZ-containing | 1 | 0.61 (0.52–0.73) | <0.001 | 0.014 | NA | NA | |
| TMZ-free | 0 | NA | NA | NA | NA | NA | ||
| GBM type | Newly diagnosed | TMZ-containing | 16 | 0.47 (0.39–0.57) | <0.001 | 0.014 | 66.1% | 0.44 |
| TMZ-free | 1 | 0.93 (0.70–1.24) | 0.62 | 1 | NA | NA | ||
| Elderly | TMZ-containing | 0 | NA | NA | NA | NA | NA | |
| TMZ-free | 0 | NA | NA | NA | NA | NA | ||
| Recurrent | TMZ-containing | 6 | 0.49 (0.34–0.70) | <0.001 | 0.014 | 66% | NA | |
| TMZ-free | 2 | 0.66 (0.49–0.88) | 0.005 | 0.065 | 0% | NA | ||
HR, hazard ratio; CI, confidence interval; NA, not applicable; TMZ-containing treatment, TMZ-alone and combined radiotherapy/TMZ and combined radiotherapy/TMZ-containing chemotherapy; TMZ-free treatment, radiotherapy alone and combined radiotherapy/TMZ-free alkylation agents chemotherapy; Mixed race: patients in American studies; Bon, P for Step-down Bonferroni adjustment.