Role of platelet-to-lymphocyte count ratio (PLR), as a prognostic indicator in COVID-19: A systematic review and meta-analysis.

Sarkar, Soumya; Kannan, Sundara; Khanna, Puneet; Singh, Akhil Kant

BACKGROUND Prognostic predictors are of paramount interest for prompt intervention and optimal utilization of the healthcare system in this ongoing context of the COVID-19 pandemic. The platelet-to-lymphocyte count ratio (PLR), has been emerged as a potential tool for risk stratification of critically ill patients with sepsis. The current systematic review explores the utility of PLR as a prognostic predictor of COVID-19 patients. METHODS We screened the electronic databases till 15th May 2021 after enrolling in PROSPERO (CRD42021220269). Studies evaluating the association between PLR on admission and outcomes in terms of mortality and severity among COVID-19 patients are included. RESULTS We retrieved 32 studies, with a total of 2768 and 3262 COVID-19 patients for mortality and disease severity outcomes. Deceased and critically ill patients had higher PLR levels on admission in comparison to survivors and non-severe patients. (MD=66.10; 95%CI 47.75-84.44; p<0.00001and MD = 86.74;95%CI 67.7-105.7; p<0.00001, respectively). However, the evidence is of low quality. CONCLUSIONS A higher level of PLR on admission in COVID-19 patients is associated with increased morbidity and mortality. However, further studies regarding the cut-off value of PLR are the need of the hour. This article is protected by copyright. All rights reserved.