Comparative efficacy and safety of ferrous sulfate versus ferric carboxymaltose in different forms of anemia: A systematic review highlighting data discrepancies

Introduction . This article discusses modern therapeutic problems and previously published data on iron deficiency correction using ferrous sulfate (FS) and ferric carboxymaltose (FCM). The data obtained are analyzed and compared based on the age of the study, the clinical entity of anemia, sample size, types of research and dosages of the drugs used. Aim . To conduct a systematic comparative analysis of the efficacy and safety of FS versus FCM for the correction of iron deficiency in various nosological forms of anemia. Materials and methods . A systematic literature search was performed in the PubMed database for the period from January 1, 2008, to February 1, 2026. Inclusion criteria were direct comparative studies or meta-analyses comparing FCM with FS in adult patients with anemia. Primary outcomes were efficacy (increase in hemoglobin level) and safety (incidence of adverse events). Results . Fourteen publications were included in the analysis. A key data discrepancy was identified: all four meta-analyses indicated a statistically significant superiority of FS over FCM in both efficacy (e.g., greater Hb increase by 4.9–8.5 g/L; p < 0.05) and safety profile. However, in three direct comparative randomized controlled trials meeting the criteria, the results for efficacy and tolerability were comparable. The vast majority of studies (19 mentions) were focused not on classic iron deficiency anemia (IDA), but on anemia of chronic disease (primarily in pregnant women), while true IDA was represented in only two works. Conclusion. The existing evidence demonstrates a significant discrepancy between the results of meta-analyses and direct comparisons of FS and FCM. The available data do not allow for a definitive conclusion about the superiority of one drug over the other, especially for the population with classic IDA, and highlight the need for targeted comparative studies in this area.