Summary of findings for the main comparison. Benefits and harms of iron supplementation for chemotherapy‐induced anemia.
| Benefits and harms of iron supplementation for chemotherapy‐induced anemia | |||||
|
Patient or population: people diagnosed with chemotherapy‐induced anemia
Settings: in‐hospital/outpatient
Intervention: iron supplementation to erythropoiesis‐stimulating agents or iron alone Comparison: erythropoiesis‐stimulating agents alone | |||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No of Participants (studies) | Quality of the evidence (GRADE) | |
| Assumed risk | Corresponding risk | ||||
| Control | Benefits and harms of iron supplementation | ||||
| Overall survival | None of the included studies reported data on overall survival | ||||
| Hematopoietic response | Study population | RR 1.17 (1.09 to 1.26) | 1712 (7 studies, 11 comparisons) | ⊕⊕⊕⊕ high | |
| 632 per 1000 | 740 per 1000 (689 to 796) | ||||
| Moderate## | |||||
| 574 per 1000 | 672 per 1000 (626 to 723) | ||||
| Red blood cell transfusion | Study population | RR 0.74 (0.6 to 0.92) | 1719 (7 studies, 11 comparisons) | ⊕⊕⊕⊝ moderate1 | |
| 195 per 1000 | 144 per 1000 (117 to 179) | ||||
| Moderate## | |||||
| 167 per 1000 | 124 per 1000 (100 to 154) | ||||
| Median time to hematopoietic response | Not applicable# |
HR 0.93 (0.67 to 1.28) |
1042 (5 studies, 7 comparisons) | ⊕⊕⊝⊝ low1,2 | |
|
Mean change in hemoglobin (better indicated by higher values) |
The mean change in hemoglobin in the intervention groups was 0.48 higher (0.10 higher to 0.86 higher) |
MD 0.48 (0.10 to 0.86) |
827 (3 studies, 7 comparisons) | ⊕⊕⊝⊝ low1,3 | |
|
Quality of life (better indicated by higher values) |
The mean quality of life in the intervention groups was 0.01 standard deviations higher (0.10 lower to 0.12 higher) |
SMD 0.01 (‐0.10 to 0.12) |
1124 (3 studies, 4 comparisons) | ⊕⊕⊕⊕ high4 | |
| Thromboembolic events | Study population | RR 0.95 (0.54 to 1.65) | 783 (3 studies) | ⊕⊕⊕⊝ moderate1 | |
| 62 per 1000 | 58 per 1000 (33 to 102) | ||||
| Moderate## | |||||
| 62 per 1000 | 59 per 1000 (33 to 102) | ||||
| Treatment‐related mortality | Not applicable** | Zero events** | 997 (4 studies, 6 comparisons) | ⊕⊕⊕⊕ high5 | |
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; HR: Hazard ratio; MD: Mean difference;RR: Risk ratio; SMD: Standardized mean difference | |||||
| GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate. | |||||
1Downgraded the quality of evidence by one level due to imprecision (the pooled estimate had wider confidence intervals). 2We noticed substantial heterogeneity among these studies. However, the type of iron used explained the presence of heterogeneity. Nonetheless, we downgraded the quality of evidence by one for the observed inconsistency. 3We noticed substantial heterogeneity among these studies. However, the route of iron administration (oral versus intravenous) and type of iron used explained the presence of heterogeneity. Nonetheless, we downgraded the quality of evidence by one for the observed inconsistency. 4We did not observe statistically significant heterogeneity among the included studies for the outcome of quality of life (I² = 0%, P = 0.54). However, it is important to note that quality of life data were reported in four studies (Auerbach 2004a; Bastit 2008; Steensma 2011a; Auerbach 2010) but were extractable from only three studies (Bastit 2008; Steensma 2011a; Auerbach 2010). The studies by Bastit et al, (Bastit 2008), and Auerbach et al, (Auerbach 2010), used the Functional Assessment of Cancer Therapy‐Fatigue scale, while the study by Steensma et al, (Steensma 2011a), used the Functional Assessment of Cancer Therapy‐Anemia scale for assessment of quality of life. Owing to the variation in the scales used, the data from these three studies were converted to the standardized mean difference and then pooled. 5Four studies reported data on treatment‐related mortality.
**Due to zero events we were not able to conduct meta‐analysis of these data.
#Data were available as median and range, and hence were converted to log hazard ratio using the cumulative hazard log‐log transform method.
##The moderate control risk was calculated via GRADEpro software based on clinical experience of the review authors working in the field of hematological disorders.