Impact of inflammatory status on intestinal iron absorption in older hospitalized patients.

BACKGROUND AND OBJECTIVE

Iron deficiency is prevalent among geriatric hospitalized patients, often coinciding with inflammation. This study aimed to determine a critical C-reactive protein (CRP) threshold for sufficient intestinal iron absorption using standardized tests.

SUBJECTS/METHODS: This retrospective, cross-sectional study was conducted in a geriatric acute care unit. Serum iron and CRP levels were measured before breakfast and two- and four-hours after ingestion of two iron capsules. Intestinal iron absorption was calculated by subtracting baseline values from those obtained after the test, with an increase of 100 ug/dl indicating sufficient absorption. Patients were categorized into six CRP groups: ≤0.50, 0.51-2.50, 2.51-5.0, 5.1-7.50, 7.51-10.0, and ≥10.1 mg/dl.

RESULTS

The study included 59 participants (73% females, age range 71-99). Iron absorption was highest in groups with lower CRP levels ≤0.50 to 2.5 mg/dl) and declined significantly as CRP increased, particularly beyond 5 mg/dl. The most significant decline was noted in patients with CRP ≥ 10.1 mg/dl. A negative correlation between inflammation, as measured by CRP, and iron absorption was found. As CRP levels escalate, there is a significant reduction in the increase of serum iron levels after 2 h. A regression analysis showed that only elevated CRP levels significantly reduced serum iron increments post-iron supplementation (P = 0.004), while other factors such as age, sex, body mass index, frailty, weight loss, hemoglobin and nutritional status had no significant impact.

CONCLUSION

A CRP level above 5 mg/dl is indicative of significantly impaired intestinal iron absorption in older patients, underscoring the critical influence of inflammation on iron metabolism.