Abstract:
Background: Covid-19 disease caused by SARS-CoV-2 had a rapid global spread leading to a
pandemic with high mortality. Therefore, it is imperative to predict the mortality of the patients
beforehand and generate cut-off values that support the prediction.
Objectives: To study the predictive role of inflammatory markers and to generate optimal cutoff
values of Covid-19 patients admitted to Intensive Care Units (ICUs)
Method: A retrospective cohort study was conducted with 219 Covid-confirmed patients admitted
to ICUs of the University Hospital KDU from June to December 2021. Patients without a
confirmatory diagnosis for Covid-19 infection (by PCR or RAT), with missing records and
patients with malignancy were excluded. Bed headnotes were traced from medical records to
extract the peak values of inflammatory markers [C-Reactive Protein (CRP), Lactate
Dehydrogenase (LDH), procalcitonin, serum ferritin, neutrophil-lymphocyte ratio (N/L ratio)] and
patient outcomes (deceased or discharged). Correlation between inflammatory markers and patient
outcomes was assessed using Point Biserial Correlation. Optimal cut-off values of the
significantly correlated inflammatory markers were predicted by Receiver Operating
Characteristics (ROC) curve and Area Under the ROC curve (AUC). p<0.05 was considered as
statistically significant.
Results: Among 219 patients, 119 patients were deceased, and 100 patients were discharged. CRP
(r=0.432), LDH (r=0.194), procalcitonin (r=0.177) and N/L ratio (r=0.371) showed statistically
significant positive correlations with poor patient outcomes while serum ferritin depicted a
negative correlation. The ROC analysis showed that AUC for CRP was 0.762 (sensitivity=0.731
and specificity=0.75), which is higher than the AUCs of N/L ratio (0.755), LDH (0.697) and
procalcitonin (0.685). The significant optimal cut-off values of CRP, LDH, procalcitonin, and N/L
ratio predicting mortality were 158.43 mg/L, 749.50 U/L, 0.345 ng/mL and 14.465, respectively.
Conclusions: Study suggests that CRP, LDH, procalcitonin and N/L ratio along with their cut-off
values possess a potential predictive role in determining the mortality of Covid-19 patients. Less
number of laboratory investigations for serum ferritin, missing values of laboratory parameters
and conducting a retrospective study are the limitations of the study.
Keywords: Covid-19, Cutoff values, Inflammatory markers, Patient outcomes
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