Prognostic value of Platelet-to-lymphocyte ratio in hospitalized patients with COVID-19 pneumonia

ABSTRACT

Platelet-to-lymphocyte ratio (PLR) is a simple biomarker of inflammation that can be measured from a routinely blood count. Various studies showed that PLR had a prognostic value in various conditions such us sepsis, acute pulmonary embolism and malignant tumors. We aimed to determine the prognostic value of the platelet-to-lymphocyte ratio (PLR) in moderate to severe COVID patients. We conducted a retrospective study including 245 patients with COVID-19 pneumonia hospitalized in the pulmonology department of the military hospital of Tunis between September 2020 and December 2021. The optimal cut-off value, sensitivity and specificity of PLR were determined by analysis of receiver operating characteristic (ROC) curve. The population was majority male (72,7 %) with a mean age of 63 +/- 13 years old. Obesity was the most common comorbidity (50%) followed by hypertension (39,6%) and diabetes (39, 2%). The common clinical manifestations were shortness of breath (79,2%), cough (72,4%) and fever (60,8%). The high PLR group had more severe form of the disease on admission (p=0,03). There were no association between PLR and mean hospital stay(p=0,2). Patients with high PLR had more complications (p=0,04), more intensive care unit referrals (p=0,04) and a higher incidence of mortality (p=0,02). A significant correlation between PLR and mortality was observed when a cut-off of 403 was considered as a differentiating benchmark with a sensitivity of 70% and a specificity of 84%, an area under the curve equal to 0.768 and p=0.009. In conclusion, PLR could be a valuable biomarker to predict disease progression in patients with moderate to severe COVID-19.