Systematic reviews and meta-analyses are an essential part of data examination, which, alongside randomized controlled trials, provide valuable information to enable informed decision making in clinical practice. In an update to their 2008 meta-analysis, Dr Shepshelovich and colleagues review studies comparing intravenous (IV) iron formulations with oral iron therapies in patients with CKD.
The aim of this meta-analysis was to examine the data for oral iron therapies vs intravenous iron preparations in patients with CKD stages 3-5 or 5D. The primary outcome was defined as the percentage of patients achieving an increase in haemoglobin greater than 1 g/dL. Secondary outcomes included serum ferritin levels and use of an erythropoiesis-stimulating agent (ESA) or blood transfusion.
Iron therapy in non-dialysis patients
For their analysis of non-dialysis patients, Shepshelovich et al examined studies enrolling patients with eGFR<60mL/min/1.73 m. Data from five trials were suitable for analysis of the primary outcome and the risk ratio of percentage of patients reaching a haemoglobin response >1 g/dL with IV iron compared to oral iron was 1.61 (95%CI, 1.39-1.87; Z=6.31 P<0.00001), meaning that patients treated with IV iron were more likely to reach a haemoglobin response of >1g/dL. The data remained in favour of IV iron when the studies were analysed according to risk of bias, the concern being that results will overestimate or underestimate the true intervention effect.
Serum ferritin levels were available from 10 trials, and found to be significantly higher in the IV iron group compared to the oral iron group (mean difference, 238.9ng/mL [95% CI, 194.3-283.5ng/mL]; Z=10.50; P<0.00001).
Iron therapy in dialysis patients
The study selection process identified 3 studies for analysis of the primary outcome and included patients receiving either peritoneal dialysis or haemodialysis. The risk ratio of percentage of patients reaching a haemoglobin response > 1 g/dL with IV iron compared to oral iron was 2.14 ([95% CI 1.68, 2.72]; Z=6.15 P<0.00001).
Again, serum ferritin levels were significantly higher in the IV iron group compared to the oral iron group (mean difference,238 ng/mL [95% CI, 74.7-401.4ng/mL]).
Safety analysis across all patients
The authors also present safety data for CKD stages 3-5 and dialysis patients together. They found no difference between IV iron and oral iron for both serious and any adverse events examined, including all-cause mortality and risk of infection. IV iron patients had a higher risk of hypotension but a significantly lower risk of gastrointestinal side effects compared with oral iron.
Shepshelovich concludes that thee follow-up meta-analysis highlights the benefits of utilizing IV iron in stages 3-5 CKD patients, which would support its more widespread use in this group and a status as the preferred iron treatment for both dialysis and non-dialysis dependent patients.
- Rozen-Zvi B, Gafter-Gvili A, Paul M, Leibovici L, Shpilberg O, Gafter U. Intravenous versus oral iron supplementation for the treatment of anemia in CKD: systematic review and meta-analysis. Am J Kidney Dis. 2008;52(5):897-906. Available at: http://www.ajkd.org/article/S0272-6386(08)01060-3/abstract. Accessed November 8, 2013.
- Shepshelovich D, Rozen-Zvi B, Avni T, Gafter U, Gafter-Gvili A. Intravenous Versus Oral Iron Supplementation for the Treatment of Anemia in CKD: An Updated Systematic Review and Meta-analysis. Am J Kidney Dis. 2016;68(5):677-690. doi:10.1053/j.ajkd.2016.04.018.
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