Intravenous iron shows safe and beneficial outcomes for patients with bacterial infection and anemia

Treatment with intravenous (IV) iron significantly improved survival and increased hemoglobin levels in patients with iron-deficiency anemia who were hospitalized for an acute bacterial infection, according to an analysis of data from more than 85,000 patients. 

Our data show that it is safe to give IV iron to patients who have both iron-deficiency anemia and an acute bacterial infection, and that, compared with untreated patients, those treated with IV iron have better overall survival and higher hemoglobin levels."

Haris Sohail, MD, lead author, a fellow in hematology-oncology at Charleston Area Medical Center in West Virginia

IV iron is a standard treatment for severe iron-deficiency anemia, but its use in patients with both iron-deficiency anemia and an acute bacterial infection is controversial, Dr. Sohail said. Studies have shown that in laboratory experiments, certain bacteria can multiply when iron is added, he said. Although this effect has not been confirmed in human studies, he said, treatment guidelines have long recommended against giving IV iron to patients with active bacterial infections due to concern that the treatment could worsen the infection.

In this study, Dr. Sohail and his colleagues searched a large database of de-identified data from patients treated at medical centers across the United States for patients aged 18 and over with iron-deficiency anemia who were hospitalized with an acute bacterial infection between 2000 and 2024.

They collected data for over 85,000 patients with the five most common acute bacterial infections treated in U.S. hospitals – over 27,000 with pneumonia, over 23,000 with urinary tract infections, over 15,000 with methicillin-resistant staphylococcus aureus (MRSA), over 13,000 with cellulitis (a skin infection), and over 7,000 with colitis (inflammation of the colon) – as well as 143 patients with bacterial meningitis (inflammation of the membranes covering the brain and spinal cord).

The researchers then compared outcomes for patients who received IV iron treatment and those who did not. They looked at how many patients in each group died within 14 or 90 days, how long they spent in the hospital, and how much their hemoglobin levels increased at 60 to 90 days after IV iron treatment compared with the levels before treatment.

For every infection except meningitis, results showed that patients treated with IV iron were statistically significantly less likely to die within 14 or 90 days and had larger increases in hemoglobin levels than patients who did not receive IV iron. In patients with meningitis, IV iron did not improve survival, but did not worsen outcomes.

"The survival benefit of IV iron was seen across different types of infections, with the biggest improvements seen in patients with pneumonia, MRSA bacteria in the blood, and colitis," Dr. Sohail said. While patients who received IV iron stayed slightly longer in the hospital, the difference was small – only about four to six hours – and not considered clinically meaningful, he said.

The small number of patients with bacterial meningitis likely explains why the findings for that infection were not statistically significant, Dr. Sohail said. He added that because the study reviewed the records of patients treated in the past, it can show only an association between IV iron and patient outcomes but cannot prove causation. Additional study limitations, he said, are that the database the researchers used did not provide detailed information about specific bacteria or iron doses, and the findings mainly apply to hospitalized patients with both iron-deficiency anemia and an active bacterial infection.

"Our findings support consideration of the use of IV iron as a safe additional therapy for patients who are hospitalized with both iron-deficiency anemia and an acute bacterial infection," he said, adding that a next step would be to confirm these findings in a randomized controlled trial.

Haris Sohail, MD, of Charleston Area Medical Center, will present this study on Sunday, December 7, 2025, at 3:25 p.m. Eastern time during the plenary scientific session in West Hall D2 of the Orange County Convention Center.