Platelet-to-Lymphocyte Ratio (PLR) Is a Potential Biomarker for Predicting Severity and Mortality in COVID-19 Patients: A Retrospective Study

Soroush Mohammadi; Ayoub Tavakolian; Sahar Shahabipour

Platelet-to-Lymphocyte Ratio (PLR) Is a Potential Biomarker for Predicting Severity and Mortality in COVID-19 Patients: A Retrospective Study

Authors

Soroush Mohammadi Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Science, Mashhad, Iran.
Ayoub Tavakolian Mashhad university of medical sciences
Sahar Shahabipour Student Research Committee, Sabzevar University of Medical Sciences, Sabzevar, Iran.

Keywords:

COVID-19, PLR, platelet-to-lymphocyte ratio, severity, mortality

Abstract

The Platelet-to-Lymphocyte Ratio (PLR) has been implicated as a potentially significant biomarker, with its elevation possibly associated with increased severity and mortality rates in COVID-19 patients. This study aimed to evaluate the correlation between the PLR and the prognosis of COVID-19 patients. This was a retrospective comparative cross-sectional study on 270 patients with RT-PCR-confirmed COVID-19 admitted to Vaseie Hospital in Sabzevar, Iran from March 2020 to July 2020. The laboratory and clinical results, demographic findings, and treatment data were collected and analyzed. The mean age of patients (150 male; 120 female) was 57.52±17.76 years. The mean PLR on the first day of hospitalization was 13.55±11.71 (ranging from 1.18 to 74.76). The mean length of hospital stay was 6.21±4.59 days (ranging from 1 to 28 days). Based on the medical records, 86.7% of patients survived and 13.3% of patients lost their lives. According to the results, there was not a significant sex difference in PLR (P=0.439). However, the differences in PLRs between different groups according to mortality, mechanical ventilation, and vasopressor drug use were associated with higher mean values of PLR (P<0.05). There was a robust positive statistically significant correlation between PLR and the proportion of neutrophils in the white blood cell count (WBC) (r=0.791; P<0.001) and a weak correlation with respiratory rate (r=0.175; P=0.004) and hospitalization time (r=0.137; P=0.025). However, PLR didn’t correlate significantly with blood pressure (r=0.033; P=0.587) and age (r=0.054; P=0.379). PLR levels were higher in non-survivors, those requiring mechanical ventilation, and patients receiving vasopressors. These data could help particularly in identifying those at higher risk of more severe disease.

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Platelet-to-Lymphocyte Ratio (PLR) Is a Potential Biomarker for Predicting Severity and Mortality in COVID-19 Patients: A Retrospective Study