Role of preoperative intravenous iron therapy to correct anemia before major surgery: a systematic review and meta-analysis.
Study Goal
The researchers aimed to determine whether preoperative intravenous iron supplementation reduces the need for allogeneic blood transfusions and increases hemoglobin levels in patients with preoperative anemia.
Results Summary
Preoperative IV iron supplementation significantly reduced blood transfusions by 16% and increased hemoglobin levels both preoperatively and postoperatively, without increasing adverse effects compared to placebo or oral iron.
Population
Patients with preoperative anemia requiring surgery.
Effective Dosage
Not specified in the abstract.
Duration
Follow-up > 4 weeks postoperatively.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Preoperative intravenous iron (IV) | decrease | allogeneic blood transfusion (ABT) | participants with preoperative anemia | 16% (risk ratio (RR): 0.84, 95% confidence interval [CI]: 0.71, 0.99, p = 0.04) | significantly decreases | #1 |
Preoperative IV iron supplementation | decrease | ABT | 1039 participants | 16% (risk ratio (RR): 0.84, 95% confidence interval [CI]: 0.71, 0.99, p = 0.04) | significantly decreases | #2 |
IV iron | increase | hemoglobin levels | - | mean difference [MD] between the study groups: 7.15 g/L, 95% CI: 2.26, 12.04 g/L, p = 0.004 | increased | #3 |
IV iron | increase | hemoglobin levels | - | MD: 6.46 g/L, 95% CI: 3.10, 9.81 g/L, p = 0.0002 | increased | #4 |
Iron injection | no change | non-serious adverse effects | - | RR: 1.13, 95% CI: 0.78, 1.65, p = 0.52 | was not associated with increased incidence | #5 |
Iron injection | no change | serious adverse effects | - | RR: 0.96, 95% CI: 0.44, 2.10, p = 0.92 | was not associated with increased incidence | #6 |
intravenous iron supplementation | decrease | the blood transfusions rate | - | - | is associated with a significant decrease | #7 |
intravenous iron supplementation | increase | hemoglobin concentrations | - | - | modest hemoglobin concentrations rise | #8 |
BACKGROUND: Preoperative anemia is a common comorbidity that often necessitates allogeneic blood transfusion (ABT). As there is a risk associated with blood transfusions, preoperative intravenous iron (IV) has been proposed to increase the hemoglobin to reduce perioperative transfusion; however, randomized controlled trials (RCT) investigating this efficacy for IV iron are small, limited, and inconclusive. Consequently, a meta-analysis that pools these studies may provide new and clinically useful information. METHODS/DESIGN: Databases of MEDLINE, EMBASE, EBM Reviews; Cochrane-controlled trial registry; Scopus; registries of health technology assessment and clinical trials; Web of Science; ProQuest Dissertations and Theses; Clinicaltrials.gov; and Conference Proceedings Citation Index-Science (CPCI-S) were searched. Also, we screened all the retrieved reference lists. SELECTION CRITERIA: Titles and abstracts were screened for relevance (i.e., relevant, irrelevant, or potentially relevant). Then, we screened full texts of those citations identified as potentially applicable. RESULTS: Our search found 3195 citations and ten RCTs (1039 participants) that met our inclusion criteria. Preoperative IV iron supplementation significantly decreases ABT by 16% (risk ratio (RR): 0.84, 95% confidence interval [CI]: 0.71, 0.99, p = 0.04). In addition, preoperatively, hemoglobin levels increased after receiving IV iron (mean difference [MD] between the study groups: 7.15 g/L, 95% CI: 2.26, 12.04 g/L, p = 0.004) and at follow-up > 4 weeks postoperatively (MD: 6.46 g/L, 95% CI: 3.10, 9.81, p = 0.0002). Iron injection was not associated with increased incidence of non-serious or serious adverse effects across groups (RR: 1.13, 95% CI: 0.78, 1.65, p = 0.52) and (RR: 0.96, 95% CI: 0.44, 2.10, p = 0.92) respectively. CONCLUSIONS: With moderate certainty, due to the high risk of bias in some studies in one or two domains, we found intravenous iron supplementation is associated with a significant decrease in the blood transfusions rate, and modest hemoglobin concentrations rise when injected pre-surgery compared with placebo or oral iron supplementation. However, further full-scale randomized controlled trials with robust methodology are required. In particular, the safety, quality of life, and cost-effectiveness of different intravenous iron preparations require further evaluation.