Table 2.
Subgroup Analyses
| Outcome | Analysis | Number of Trials | Effect Estimate (95% CI) | p Value | p Value Between Groups |
|---|---|---|---|---|---|
| Clinical heart failure | Primary analysis | 7 | RR: 0.19 (0.09-0.40) | <0.001 | |
| RCTs | 7 | RR: 0.19 (0.09-0.40) | <0.001 | NA | |
| Retrospective trials | 0 | — | — | ||
| Previous ANT | 2 | RR: 0.27 (0.07-1.07) | 0.06 | 0.51 | |
| No previous ANT | 5 | RR: 0.15 (0.06-0.39) | <0.001 | ||
| Early BC | 1 | Not estimable | — | NA | |
| Advanced/metastatic BC | 6 | RR: 0.19 (0.09-0.40) | <0.001 | ||
| Cardiac events | Primary analysis | 8 | RR: 0.36 (0.27-0.49) | <0.001 | |
| RCTs | 6 | RR: 0.36 (0.26-0.49) | <0.001 | 0.95 | |
| Retrospective trials | 2 | RR: 0.33 (0.03-3.39) | 0.35 | ||
| Previous ANT | 2 | RR: 0.32 (0.19-0.54) | <0.001 | 0.67 | |
| No previous ANT | 6 | RR: 0.37 (0.24-0.58) | <0.001 | ||
| Early BC | 1 | RR: 0.08 (0.01-1.37) | 0.08 | 0.30 | |
| Advanced/metastatic BC | 7 | RR: 0.37 (0.27-0.50) | <0.001 | ||
| Complete response | Primary analysis | 6 | RR: 1.10 (0.75-1.61) | 0.62 | |
| RCTs | 6 | RR: 1.10 (0.75-1.61) | 0.62 | NA | |
| Retrospective trials | 0 | — | — | ||
| Previous ANT | 2 | RR: 1.27 (0.60-2.68) | 0.53 | 0.67 | |
| No previous ANT | 4 | RR: 1.05 (0.67-1.63) | 0.83 | ||
| Early BC | 0 | — | — | NA | |
| Advanced/metastatic BC | 6 | RR: 1.10 (0.75-1.61) | 0.62 | ||
| Partial response | Primary analysis | 6 | RR: 0.88 (0.75-1.02) | 0.10 | |
| RCTs | 6 | RR: 0.88 (0.75, 1.02) | 0.10 | NA | |
| Retrospective trials | 0 | — | — | ||
| Previous ANT | 2 | RR: 0.96 (0.71-1.31) | 0.81 | 0.49 | |
| No previous ANT | 4 | RR: 0.85 (0.70-1.02) | 0.07 | ||
| Early BC | 0 | — | — | NA | |
| Advanced/metastatic BC | 6 | RR: 0.88 (0.75-1.02) | 0.10 | ||
| Stable disease | Primary analysis | 4 | RR: 0.92 (0.70-1.20) | ||
| RCTs | 4 | RR: 0.92 (0.70-1.20) | 0.54 | NA | |
| Retrospective trials | 0 | — | — | ||
| Previous ANT | 1 | RR: 0.77 (0.50-1.19) | 0.25 | 0.33 | |
| No previous ANT | 3 | RR: 1.02 (0.73-1.44) | 0.90 | ||
| Early BC | 0 | — | — | NA | |
| Advanced/metastatic BC | 4 | RR: 0.92 (0.70-1.20) | 0.54 | ||
| Progression-free survival | Primary analysis | 5 | HR:0.97 (0.75-1.24) | 0.81 | |
| RCTs | 5 | HR:0.97 (0.75-1.24) | 0.81 | NA | |
| Retrospective trials | — | — | — | ||
| Previous ANT | 2 | HR:0.68 (0.49-0.94) | 0.02 | 0.007 | |
| No previous ANT | 3 | HR: 1.13 (0.95-1.34) | 0.17 | ||
| Early BC | — | — | — | NA | |
| Advanced/metastatic BC | 5 | HR: 0.97 (0.75-1.24) | 0.81 | ||
| Overall survival | Primary analysis | 6 | HR: 1.01 (0.86-1.17) | 0.92 | |
| RCTs | 5 | HR: 1.04 (0.88-1.22) | 0.65 | 0.20 | |
| Retrospective trials | 1 | HR: 0.71 (0.41-1.24) | 0.23 | ||
| Previous ANT | 2 | HR: 1.06 (0.73-1.54) | 0.75 | 0.76 | |
| No previous ANT | 4 | HR: 1.00 (0.84-1.18) | 0.97 | ||
| Early BC | 1 | HR: 1.04 (0.88-1.22) | 0.23 | 0.20 | |
| Advanced/metastatic BC | 5 | HR: 0.71 (0.41-1.24) | 0.65 |
ANT = anthracycline; BC = breast cancer; CI = confidence interval; HR = hazard ratio; RR = relative risk; NA = not applicable; RCT = randomized clinical trial.