Table 2. Summary risk estimates of the association between comorbidity and ovarian cancer survival.
| No. of studies | Summary HR (95% CIs) | I2 value (%) | Ph* | |
|---|---|---|---|---|
| Overall | 8 | 1.20 (1.11–1.30) | 31.2 | 0.179 |
| Subgroup analyses | ||||
| Geographic location | ||||
| North America | 3 | 1.23 (1.11–1.36) | 1.9 | 0.361 |
| Europe | 4 | 1.23 (1.10–1.38) | 32.7 | 0.216 |
| Australia | 1 | 1.02 (0.86–1.21) | N/A | N/A |
| Study period (years) | ||||
| ≥7 | 4 | 1.19 (1.05–1.34) | 43.0 | 0.154 |
| <7 | 4 | 1.23 (1.08–1.39) | 37.6 | 0.186 |
| Adjustment for potential confounders or prognostic factors | ||||
| Age at diagnosis | ||||
| Yes | 8 | 1.20 (1.11–1.30) | 31.2 | 0.179 |
| No | 0 | N/A | N/A | N/A |
| Tumor stage | ||||
| Yes | 8 | 1.20 (1.11–1.30) | 31.2 | 0.179 |
| No | 0 | N/A | N/A | N/A |
| Tumor grade | ||||
| Yes | 4 | 1.26 (1.05–1.50) | 69.5 | 0.020 |
| No | 4 | 1.19 (1.09–1.29) | 0 | 0.961 |
| Tumor histology | ||||
| Yes | 4 | 1.25 (1.04–1.51) | 69.8 | 0.019 |
| No | 4 | 1.19 (1.10–1.29) | 0 | 0.969 |
| Cancer treatment | ||||
| Yes | 2 | 1.31 (1.12–1.55) | 0 | 0.368 |
| No | 6 | 1.18 (1.08–1.29) | 36.7 | 0.162 |
| Residual tumor | ||||
| Yes | 2 | 1.18 (1.08–1.19) | 0 | 0.854 |
| No | 6 | 1.23 (1.08–1.40) | 50.4 | 0.073 |
| Three aforementioned factors | ||||
| Yes | 6 | 1.21 (1.09–1.35) | 49.7 | 0.077 |
| No | 2 | 1.19 (1.06–1.34) | 0 | 0.620 |
| Four aforementioned factors | ||||
| Yes | 5 | 1.22 (1.08–1.38) | 59.7 | 0.042 |
| No | 3 | 1.19 (1.07–1.33) | 0 | 0.883 |
CI: confidence interval; HR: hazard ratio; N/A: not available.
*P value for heterogeneity within each subgroup.