Comparing the Efficacy of Intravenous Versus Oral Iron Supplementation for Anemic Patients With Inflammatory Bowel Disease: A Meta-Analysis

Iron deficiency anemia (IDA) is a frequent complication in inflammatory bowel diseases (IBDs) and adversely affects patient outcomes and quality of life. Oral iron supplementation is widely used but can be poorly tolerated and less effective during active inflammation. Intravenous (IV) iron supplementation bypasses intestinal absorption barriers, but its comparative efficacy in IBD remains under debate. This study aims to compare the efficacy of IV versus oral iron supplementation in achieving effective hemoglobin increases in patients with IBD-associated anemia. A systematic search of PubMed, Web of Science, Scopus, Medline, the Cochrane Library, and Google Scholar was conducted up to March 2022, yielding 711 records. After removing duplicates and applying inclusion criteria, seven studies (six randomized controlled trials and one prospective study), involving 1,029 patients, were included. Data were pooled using a fixed-effects model to calculate odds ratios (ORs) with 95% confidence intervals (CIs). The primary outcome was the proportion of patients achieving a clinically meaningful hemoglobin increase. Heterogeneity was assessed using the I² statistic, and publication bias was evaluated using funnel plots. Across the seven included studies, IV iron supplementation was significantly more effective than oral iron in increasing hemoglobin levels in IBD-associated anemia. The pooled OR was 1.45 (95% CI: 1.11-1.90; p = 0.006), favoring IV iron. Heterogeneity was minimal (I² = 2%, p = 0.41). Funnel plot analysis showed symmetrical distribution, suggesting a low likelihood of publication bias. In conclusion, IV iron supplementation provides a statistically and clinically significant advantage over oral iron for treating anemia in patients with IBD, with consistent results across diverse populations and minimal heterogeneity. These findings support guideline recommendations favoring IV iron, particularly in patients with active disease, intolerance to oral formulations, or the need for rapid anemia correction.