Inflammatory Biomarkers as Predictors of In‐Hospital Mortality in Critically Ill COVID‐19 Patients: A Retrospective Cohort Study
Siamak Rimaz, Orchideh Amoie Foumani, Hamid Hoseinzadeh, Mohammad Shokri, Mohammad Haghighi, Mahboobeh Gholipour, Nastaran Najd, Amirhossein Azariyan, Mohammadreza Mobayen, Mahsa SadeghiABSTRACT
Background and Aim
Inflammatory biomarkers have been proposed as prognostic indicators in COVID‐19; however, their prognostic associations within critically ill ICU‐admitted patients remain of interest. This study aimed to evaluate the associations of selected inflammatory biomarkers with in‐hospital mortality and their discriminatory performance among critically ill COVID‐19 patients.
Methods
In this retrospective cohort study, 244 adult patients with confirmed COVID‐19 pneumonia admitted to the ICU between August 2020 and June 2021 were analyzed. Disease severity was assessed using the ISARIC 4 C Mortality Score. Associations between inflammatory biomarkers and mortality were evaluated using univariable and multivariable logistic regression, and discriminatory performance was assessed using ROC curve analysis.
Results
The in‐hospital mortality rate was 90.6%. ESR and LDH levels were significantly higher in non‐survivors. In a biomarker‐restricted multivariable logistic regression model, ESR (OR 1.023 per 1 mm/h increase; 95% CI 1.004–1.042; p = 0.016) and LDH (OR 1.002 per 1 U/L increase; 95% CI 1.000–1.003; p = 0.009) remained significantly associated with in‐hospital mortality after mutual adjustment for the other prespecified inflammatory biomarkers. LDH demonstrated good discriminatory performance (AUC 0.725; 95% CI 0.645–0.805). ESR showed modest discriminatory performance (AUC 0.646; 95% CI 0.559–0.732).
Conclusion
ESR and LDH remained significantly associated with in‐hospital mortality after adjustment for the other prespecified inflammatory biomarkers. These findings suggest that ESR and LDH may provide adjunctive prognostic information in critically ill ICU patients; however, they should be interpreted in the context of the biomarker‐restricted model and the limited adjustment set. Confirmation in larger prospective studies incorporating established clinical prognostic factors is warranted.