Exploring the relationship between serum iron, patient morbidity, mortality, and length of hospitalization in a burn center Free

Iron is ubiquitous within the human body and serves numerous functions. Given its roles in oxygen transport, immune function, and wound healing, one might theorize that serum iron serves as a vital biomarker in patients suffering from burn injuries. According to the American Burn Association, there are approximately 450,000 severe burn injuries reported annually; however, the correlation between serum iron levels and clinical outcomes in these patients is not well understood. Previous studies have yielded contradictory findings regarding the effect of iron on recovery from burns. Some research has suggested iron supplementation may assist the recovery process, while other studies caution against it due to iron's pro-inflammatory properties.

This retrospective study evaluated 111 adult patients admitted to the Burn Intensive Care Unit (BICU) at a Level I trauma center in the US between 2011 and 2022. Median age was 54 years; 59.5% male, 80.6% White, and 45.3% Hispanic/Latino. Data included demographics, burn characteristics (TBSA, depth), comorbidities (48.2% hypertension, 30.9% diabetes), and interventions such as intubation (52.3%), tracheotomy (8.1%), and cardiac arrest (4.5%). Serum iron was obtained within 72 hours of admission. Data were processed in Excel and analyzed in R (v4.3.2). Descriptive statistics summarized patients; univariable analyses used Mann-Whitney and Fisher's exact tests. Multivariable logistic regression modeled mortality; multivariable linear regression with robust errors assessed length of stay (LOS). Covariates included age, BMI, TBSA, burn depth, comorbidities, and events, with serum iron examined continuously and dichotomously (<60 vs ≥60 mcg/dL). Interaction terms, like cardiac arrest with tracheotomy, were explored. Model adequacy was checked via ROC curves, Hosmer-Lemeshow tests, and AIC.

No significant difference in median serum iron was found between survivors and non-survivors, but patients with serum iron ≥60 mcg/dL had lower odds of mortality (OR=0.21, 95% CI: 0.00–64.15) and stayed about 11 days less than those with <60 mcg/dL. Mortality was more strongly linked to age, burn severity, and critical events; each additional year of age and 1% increase in 3rd-degree burn raised death risk. Cardiac arrest was the strongest mortality predictor, while intubation, bronchoscopy, and tracheotomy were more common in non-survivors and extended hospital stays. A modest but significant negative correlation (Spearman Rho = -0.19, p=0.042) between serum iron and LOS suggests higher iron levels associated with shorter admissions and better outcomes.

The results underscore iron's multifaceted role in the context of burn recovery, where sufficient serum levels may promote healing while excess iron may be detrimental by leading to excess oxidative stress. The identification of a threshold at 60 mcg/dL suggests a possible therapeutic window for iron supplementation. However, the limitations of this study, such its single-center design and the absence of baseline iron measurements, prevent us from making definite conclusions. These findings clash with those from earlier studies that reported no mortality benefit with iron therapy. This may be attributable to differences in patient demographics or treatment protocols. Notably, the association observed between elevated iron levels and reduced length of hospitalization supports emerging evidence that adequate iron availability may facilitate wound healing and lower infection risk among burn patients. The findings of this study make the case for the inclusion of serum iron monitoring in standard protocols for burn care, offering preliminary evidence that targeted iron supplementation for patients exhibiting levels below 60 mcg/dL may improve outcomes. However, additional research is necessary to establish causality. Future multicenter investigations should focus on the longitudinal dynamics of iron levels and incorporate other biomarkers, such as ferritin and transferrin saturation, to fully elucidate the role of iron in burn recovery. These findings highlight the complex interactions between iron metabolism and burn pathophysiology, emphasizing the need for personalized nutritional support strategies in critical burn care settings while paving the way for more extensive investigations aimed at optimizing iron management for burn patients.