The relationship between serum ferritin level and clinical outcomes in sepsis based on a large public database

Deciphering the iron enigma: Navigating the complexities of iron metabolism in critical illness

Iron is a double-edged sword! Despite being essential for numerous physiological processes of the body, a dysregulated iron metabolism can result in tissue damage, exaggerated inflammatory response, and increased susceptibility to infection with certain pathogens that thrive in iron-rich environment. During sepsis, there is an alteration of iron metabolism, leading to increased transport and uptake into cells. This increase in labile iron may cause oxidative damage and cellular injury (ferroptosis) which progresses as the disease worsens. Critically ill patients are often complicated with systemic inflammation which may contribute to multiple organ dysfunction syndrome or sepsis, a common cause of mortality in intensive care unit. Originally, ferritin was known to play an important role in the hematopoietic system for its iron storage capacity. Recently, its role has emerged as a predictor of poor prognosis in chronic inflammation and critical illnesses. Apart from predicting the disease outcome, serum ferritin can potentially reflect disease activity as well.

An Exploratory Analysis of Routine Ferritin Measurement Upon Admission and the Prognostic Implications of Low-Grade Ferritinemia During Inflammation

BACKGROUND

Serum ferritin is usually measured in the presence of anemia or in suspected iron overload syndromes. Ferritin is also an acute-phase protein that is elevated during systemic inflammation. However, the prognostic value of routinely measuring ferritin upon admission to a medical facility is not clear. Therefore, we examined the association between ferritin concentrations measured at the time of hospital admission with 30-day and long-term mortality.

METHODS

We obtained routine ferritin measurements taken within 24 hours of admission in 2859 patients hospitalized in an internal medicine department. Multiple clinical and laboratory parameters were used to assess the association between ferritin and overall mortality during a median follow-up of 15 months (interquartile range [IQR] 8-22).

RESULTS

Ferritin levels were associated with increased 30-day mortality rates (odds ratio [OR] 1.04, 95% confidence interval [CI] 1.03-1.06) for each 100 ng/mL increase. Patients with intermediate (78-220 ng/mL) and high (>221 ng/mL) ferritin concentrations (2nd and 3rd tertiles) had higher 30-day mortality rates even after adjustment for age, sex, and existing comorbidities (OR 2.05, 95% CI 1.70-2.5). Long-term overall mortality rates demonstrated a similar pattern across ferritin tertiles (hazard ratio [HR] 1.54, 95% CI 1.39-1.71).

CONCLUSIONS

Routine admission ferritin concentrations are linearly and independently correlated with excess mortality risk in hospitalized patients, even those with apparently "normal" ferritin concentrations (<300 mg/mL). Thus, low-grade ferritinemia might not be an innocent finding in the context of the inflammatory response. Its potential biological and therapeutic implications warrant future research.

A Comprehensive Review on Serum Ferritin as a Prognostic Marker in Intensive Care Units: Insights Into Ischemic Heart Disease

Serum ferritin has garnered considerable attention as a prognostic marker in intensive care units (ICUs), offering valuable insights into patient outcomes and clinical management strategies. This comprehensive review examines the role of serum ferritin in predicting outcomes among critically ill patients, with a particular focus on its implications for ischemic heart disease (IHD). Elevated serum ferritin levels have consistently been associated with adverse outcomes in ICU settings, including increased mortality, prolonged hospital stays, and higher morbidity rates. Furthermore, the relationship between serum ferritin levels and IHD underscores its potential as a biomarker for cardiovascular risk assessment in critically ill populations. The review synthesizes existing literature to highlight the predictive value of serum ferritin in assessing illness severity and guiding clinical decision-making in the ICUs. It also explores potential mechanisms linking serum ferritin to adverse outcomes and discusses implications for clinical practice. Integrating serum ferritin measurements into routine assessments could enhance prognostication and risk stratification in ICU patients, while further research is needed to elucidate optimal management strategies and therapeutic targets. Collaborative efforts between clinicians and researchers are essential to advance our understanding of serum ferritin's prognostic value in the ICUs and translate this knowledge into improved patient care and outcomes.

Ferritin-mediated neutrophil extracellular traps formation and cytokine storm via macrophage scavenger receptor in sepsis-associated lung injury

BACKGROUND

Sepsis is a severe systemic inflammatory disorder manifested by a dysregulated immune response to infection and multi-organ failure. Numerous studies have shown that elevated ferritin levels exist as an essential feature during sepsis and are able to suggest patients' prognoses. At the same time, the specific mechanism of ferritin-induced inflammatory injury remains unclear.

METHODS

Hyper-ferritin state during inflammation was performed by injecting ferritin into a mouse model and demonstrated that injection of ferritin could induce a systemic inflammatory response and increase neutrophil extracellular trap (NET) formation.Padi4-/-, Elane-/- and Cybb-/- mice were used for the NETs formation experiment. Western blot, immunofluorescence, ELISA, and flow cytometry examined the changes in NETs, inflammation, and related signaling pathways.

RESULTS

Ferritin induces NET formation in a peptidylarginine deiminase 4 (PAD4), neutrophil elastase (NE), and reactive oxygen species (ROS)-dependent manner, thereby exacerbating the inflammatory response. Mechanistically, ferritin induces the expression of neutrophil macrophage scavenger receptor (MSR), which promotes the formation of NETs. Clinically, high levels of ferritin in patients with severe sepsis correlate with NETs-mediated cytokines storm and are proportional to the severity of sepsis-induced lung injury.

CONCLUSIONS

In conclusion, we demonstrated that hyper-ferritin can induce systemic inflammation and increase NET formation in an MSR-dependent manner. This process relies on PAD4, NE, and ROS, further aggravating acute lung injury. In the clinic, high serum ferritin levels are associated with elevated NETs and worse lung injury, which suggests a poor prognosis for patients with sepsis. Our study indicated that targeting NETs or MSR could be a potential treatment to alleviate lung damage and systemic inflammation during sepsis. Video Abstract.

Association between ferritin to albumin ratio and 28-day mortality in patients with sepsis: a retrospective cohort study

OBJECTIVES

The ratio of ferritin to albumin (FAR) has been proposed as a novel prognostic indicator for COVID-19. However, the role of FAR in predicting the all-cause mortality rate in patients with sepsis has not been evaluated. Therefore, the aim of this study is to elucidate the correlation between FAR and the 28-day all-cause mortality rate in patients with sepsis.

METHODS

This study used data from the Medical Information Mart for Intensive Care IV database (v2.0) for a retrospective cohort analysis. The study focused on adult patients with sepsis who were admitted to the intensive care unit. The primary objective was to assess the predictive capability of FAR in determining the 28-day all-cause mortality rate among patients with sepsis.

RESULTS

The study involved 1553 sepsis patients in total. Based on the survival status of sepsis patients within 28 days, they were divided into two groups: a survival group consisting of 973 patients, and a death group consisting of 580 patients. The results revealed a 28-day mortality rate of 37.35% among sepsis patients. The multivariable Cox regression analysis revealed that FAR was an independent predictor of the 28-day all-cause mortality rate in patients with sepsis (hazard ratio [HR]: 1.17-1.19; 95% confidence interval 1.11-1.26; P < 0.001). The FAR demonstrated a higher area under the curve (AUC) of 61.01% (95% confidence interval 58.07-63.96%), compared to serum ferritin (60.48%), serum albumin (55.56%), and SOFA score (56.97%). Receiver operating characteristic curve (ROC) analysis determined the optimal cutoff value for FAR as 364.2215. Kaplan-Meier analysis revealed a significant difference in the 28-day all-cause mortality rate between patients with FAR ≥ 364.2215 and those with FAR < 364.2215 (P < 0.001). Furthermore, subgroup analysis showed no significant interaction between FAR and each subgroup.

CONCLUSIONS

This study revealed a significant correlation between FAR and the 28-day mortality rate in patients with sepsis. Higher FAR values were strongly associated with increased mortality rates within 28 days.