Can Ferritin and Interleukin-6 Levels Prognosticate Patients with COVID-19

Background and study aim: During the coronavirus disease 2019 (COVID-19) pandemic efforts were focused on identifying biomarkers that predict disease severity and clinical outcomes. Biomarkers, including ferritin and interleukin-6 (IL-6), have been implicated in contributing to worsening prognosis. However, there is limited data on their prognostic utility in African populations. This study aimed to determine whether serial ferritin and IL-6 measurements could serve as prognostic biomarkers for COVID-19 outcomes in a South African quaternary referral hospital.Patients and Methods: A retrospective analysis of 125 patients (≥12 years) with confirmed COVID-19 infection, admitted to Inkosi Albert Luthuli Central Hospital from January to December 2020, was conducted. Demographic, clinical, and laboratory data were extracted from electronic medical records. Patients were stratified based on outcome (alive vs. demised). Statistical analyses included binary logistic regression, the Kruskal-Wallis test, and correlation analyses to evaluate associations between serial measurements of ferritin and IL-6 levels, comorbidities, and mortality risk.Results: The cohort was predominantly female (64%), with a median age of 45.1 years (IQR: 32.0–56.0). The most prevalent comorbidities were hypertension (48.0%), diabetes mellitus (23.2%), and chronic kidney disease (CKD) (31.2%). Hypertension was associated with reduced odds of mortality (p = 0.031, OR = 0.228), while CKD significantly increased mortality risk (p = 0.001, OR = 8.768). Ferritin and IL-6 levels were significantly elevated in the demised group, with ferritin increasing from 2,127.32 ng/mL (baseline) to 10 020.2 ng/mL (endpoint) (p < 0.001) and IL-6 rising from 443.2 pg/mL to 821.03 pg/mL (p < 0.001). In contrast, alive patients exhibited stable or decreasing levels of both markers at the endpoint (ferritin: 563.96 ng/mL to 336.29 ng/mL; IL-6: 97.24 pg/mL to 18.1 pg/mL, p < 0.001). Kruskal-Wallis analysis and Receiver Operator Curve analysis confirmed significant associations between ferritin, IL-6 levels, and outcomes.Conclusion: This study provides evidence that serial ferritin and IL-6 measurements can serve as prognostic indicators in COVID-19 patients. Findings suggest that ferritin may serve as a surrogate marker for IL-6, potentially offering an alternative for risk stratification. Further prospective studies are warranted to explore the clinical applicability of these markers across diverse populations and conditions.