Association of white blood cell counts, procalcitonin, C-reactive protein, interleukin-6, troponin, and ferritin with mortality in severe COVID-19

Abstract

Objectives/Background: Since the outbreak of COVID-19, healthcare professionals suggested a wide range of recommendations in the fields of diagnosis, treatment, and prevention. Laboratory biomarkers are considered one of the crucial diagnostic tools for COVID-19, assessing its severity and progress predictor. Owing to the lack of consensus regarding changes in biomarkers and their correlations, researchers are encouraged to detect more interesting findings. A few studies were conducted in Iraq considering this aspect. This study aimed to investigate certain biomarkers in patients with severe COVID-19 and their relations to mortality outcomes. Also, this study aimed to identify the correlation between these markers in severe disease. Patients and Methods: A cross-sectional study was conducted at the Fallujah Teaching Hospital, west of Iraq, which included all admittance with severe COVID-19 between September 20, 2021, and February 30, 2022. A questionnaire was designed to collect socio-clinical characteristics and in-hospital outcomes (recovery/death). Procalcitonin (PCT) and certain biomarkers were analyzed, based on that outcome, and correlations between these markers were assessed. Results: For 75 patients who were enrolled in this study, the mean age was 62.3 ± 14.3 years, of which females constituted 62%. The most preponderance age was ≥60 years with a statistically significant higher rate of death (37.3%) when compared to other ages (P = 0.007), while other socio-clinical characteristics revealed nonsignificant differences. High PCT levels were found in 34.7% of the enrolled patients, while neutrophilia, lymphopenia, and elevated levels of troponin, ferritin, and C-reactive protein (CRP) were the prominent abnormal biomarker findings. However, only ferritin and troponin mean levels revealed significant differences in relation to the outcomes (P = 0.019 and 0.010, respectively). A moderate positive correlation was found between PCT and interleukin-6 (IL-6) (r = 0.586, P = 0.005), and also PCT correlates positively with CRP (r = 0.49, P = 0.005) and troponin (r = 0.41, P = 0.001). Additionally, there were significant positive correlations of troponin with IL-6 (r = 0.41, P = 0.005) and PCT (r = 0.37, P = 0.001). Also, IL-6 correlates positively with troponin (r = 0.62, P = 0.005). Conclusions: We found an elevated level of PCT in almost three-quarters of patients with severe COVID-19, with a non-significant difference with the specific recovery/death outcomes. In addition, high troponin levels, neutrophilia, and lymphopenia regardless of the outcome were found. Also, there were valuable correlations between certain biomarkers in patients with COVID-19.