Inflammation Impairs Iron Absorption in Hospitalised Seniors

TOPLINE:

Intestinal iron absorption efficiency after iron supplementation was higher in older hospitalised patients with C-reactive protein (CRP) levels < 5 mg/dL but declined with increasing CRP levels (inflammation), with the most marked reduction observed in those with CRP levels ≥ 10.1 mg/dL.

METHODOLOGY:

• Researchers conducted this retrospective cross-sectional study (October 2023 to February 2024) at a hospital in Germany to assess the association of intestinal iron absorption after iron supplementation (analysed using iron absorption tests) with the degree of inflammation, determined using CRP levels.
• They included 59 older hospitalised patients (mean age, 82.7 years; 73% women) with a full iron assessment at the time of admission, a transferrin saturation level below 16%, and a CRP level measured on the day of the iron absorption test. Patients who received iron replacement therapy within the prior 3 weeks or had conditions affecting iron absorption were excluded.
• Baseline serum iron and CRP levels were measured before breakfast, followed by the administration of two 100 mg of iron (II) glycine sulphate capsules. The effectiveness of iron absorption was evaluated by measuring serum iron levels after 2 and 4 hours of capsule ingestion, with an increase of 100 μg/dL from baseline considered as positive iron absorption.
• On the basis of CRP levels, patients were stratified into six groups: ≤ 0.50, 0.51-2.50, 2.51-5.0, 5.1-7.50, 7.51-10.0, and ≥ 10.1 mg/dL.

TAKEAWAY:

• The average iron absorption was higher in groups of patients with CRP levels ≤ 0.50, 0.51-2.50, and 2.51-5.0 mg/dL, with iron concentrations significantly increased from baseline at 2 hours and maintained at 4 hours.
• A decline in the efficiency of iron absorption was observed in patients with CRP levels of 5.1-7.50 mg/dL, with a marked reduction observed in those with CRP levels ≥ 10.1 mg/dL.
• Absolute changes in serum iron levels decreased with increasing CRP levels at both 2 hours (P = .006) and 4 hours (P = .049) after the test. A negative correlation was observed between inflammation and the efficiency of iron absorption over time.
• Only CRP (inflammation) and serum ferritin levels were significantly associated with an increase in serum iron levels following oral iron ingestion (P = .022 and P = .033, respectively), with increased CRP levels associated with a lower increase in serum iron levels.

IN PRACTICE:

“While intravenous iron therapy is an alternative, it is associated with a significant risk of allergic reactions and elevated healthcare costs compared to oral iron supplementation. Therefore, establishing a definitive CRP threshold could significantly enhance clinical decision-making,” the authors wrote.

“These findings underscore the vital roles of iron in the human body and highlight the need for careful management of iron supplementation in older hospitalized patients,” they added.

SOURCE:

This study, led by Baigang Wang, Marien Hospital Herne, Ruhr-University Bochum, Herne, Germany, was published online on March 27, 2025, in the European Journal of Clinical Nutrition.

LIMITATIONS:

This study did not differentiate between acute and chronic inflammation or examine the dynamics of changes in CRP levels. The investigation focused exclusively on the dynamics of iron absorption and excluded the analysis of increases in haemoglobin levels in patients with clinically evident anaemia.

DISCLOSURES:

This study received Open Access funding that was enabled and organised by Projekt DEAL, and the authors acknowledged receiving support from the Open Access Publication Fund of the Ruhr-Universität Bochum. The authors declared having no competing interests.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.