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Published on: January 16, 2019

The role of CAR and SII values in determining mortality in COVID-19 patients: a retrospective observational study

Sedat Özbay1, Orhan Özsoy1, Tansu Gençer1

  • 1Sivas Numune Hospital Department of Emergency Medicine, Sivas, Turkey.

BMC Infectious Diseases
|June 5, 2026
PubMed

Insights

The C-reactive protein (CRP) and SII (Systemic Immune-Inflammation Index) and CAR (CAR) were evaluated for their relationship with COVID-19 mortality. While SII and CAR were not independent predictors of mortality, CRP, BUN, and Creatinine were found to be significant indicators.

Area of Science:

  • Medical research
  • Infectious diseases
  • Critical care medicine

Background:

  • Coronavirus disease (COVID-19) poses a significant global health threat.
  • Understanding predictors of mortality in COVID-19 patients is crucial for clinical management.
  • Inflammatory markers are frequently altered in severe COVID-19.

Purpose of the Study:

  • To investigate the relationship between the Systemic Immune-Inflammation Index (SII), C-reactive protein (CRP) to albumin ratio (CAR), and mortality in COVID-19 patients.
  • To identify independent predictors of mortality among various laboratory parameters in COVID-19.

Main Methods:

  • Retrospective study of 1519 COVID-19 patients admitted to the emergency department.
  • Comparison of laboratory parameters including Neutrophil-lymphocyte ratio (NLR), Platelet-lymphocyte ratio (PLR), fibrinogen, D-dimer, procalcitonin, ferritin, CRP, BUN, and Creatinine between mortality and survival groups.
  • Logistic regression analysis to determine independent factors affecting mortality.

Main Results:

  • Mortality rate was 52.6% in the study cohort.
  • NLR and PLR were significantly higher in the mortality group (p < 0.001).
  • Acute-phase reactants (fibrinogen, D-dimer, procalcitonin, ferritin, CRP) were elevated in non-survivors (p < 0.001). BUN, Creatinine, AST, and CRP were identified as independent predictors of mortality (p < 0.05).

Conclusions:

  • The Systemic Immune-Inflammation Index (SII) and C-reactive protein (CRP) to albumin ratio (CAR) are not independent predictors of mortality in COVID-19 patients.
  • Certain inflammatory markers and renal function indicators (CRP, BUN, Creatinine) are significant independent predictors of mortality in COVID-19.
Abstract

Keywords:
COVID-19 mortalityEmergency departmentLaboratory parameters

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