Safety of High-Dose Intravenous Iron in Hemodialysis Patients: Results from the National Health Insurance Service (2019–2020) in South Korea

<b>Background</b>: Intravenous (IV) iron administration is used widely for treating anemia in hemodialysis (HD) patients. In this study, we investigated the safety of IV iron therapy in this population. <b>Methods</b>: This study analyzed claims data from the National Health Insurance Service (NHIS) and included patients with end-stage renal disease who were receiving HD for more than 3 months as of 1 January 2019. Monthly doses of IV iron were measured for these patients from 1 January to 30 June 2019. Patients were classified into a high- or low-dose group based on the cutoff of a monthly dose of 300 mg of iron sucrose. Study outcomes were infection-related hospitalization, cardiovascular events, and all-cause mortality and hospitalization that occurred from 1 July 2019 to 31 December 2020. <b>Results</b>: Among 33,527 HD patients, 13,609 (40.6%) and 363 (1.1%) patients were administered IV iron at doses of 1-299 mg/month and ≥300 mg/month, respectively. The mean age was 63 years, and 60.4% were men. Compared with the low-dose group, the high-dose group was younger, had higher percentages of men and medical aid recipients from the NHIS, and had higher prevalence rates of diabetes and hypertension. The rates of infection-related hospitalization, cardiovascular events, and all-cause hospitalization and mortality were not significantly higher in the high-dose than in the low-dose group. Compared with the 1-100 mg IV iron sucrose dose, higher doses were not associated with an increased risk of outcome events. <b>Conclusions</b>: High-dose IV iron administration did not increase rates of mortality or morbidity in HD patients.