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

Abstract

Prognostic predictors are of paramount interest for prompt intervention and optimal utilization of the healthcare system in the ongoing context of the COVID‐19 pandemic. The platelet‐to‐lymphocyte count ratio (PLR), has 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. We screened the electronic databases until May 15, 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 were included. 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 (mean differences [MD] = 66.10; 95% confidence interval [CI]: 47.75–84.44; p < 0.00001 and MD = 86.74; 95% CI: 67.7–105.7; p < 0.00001, respectively). A higher level of PLR on admission in COVID‐19 patients is associated with increased morbidity and mortality. However, the evidence is of low quality and further studies regarding the cut‐off value of PLR are the need of the hour.

Significance of hemogram‐derived ratios for predicting in‐hospital mortality in COVID‐19: A multicenter study

“… 51 Several systematic reviews and meta‐analyses found the role of PLR as a prognostic marker in COVID‐19. 52 , 53 However, in our study, PLR was not found to be a significant prognostic factor of mortality in multivariable analysis, which is consistent with previous studies. 54 , 55 …”

“…Like NLR, PLR has been demonstrated to be predictive of worse overall survival in cancer patients 50 and correlated with disease severity in patients with Rheumatoid arthritis 51 . Several systematic reviews and meta‐analyses found the role of PLR as a prognostic marker in COVID‐19 52,53 . However, in our study, PLR was not found to be a significant prognostic factor of mortality in multivariable analysis, which is consistent with previous studies 54,55 …”

“…51 Several systematic reviews and meta-analyses found the role of PLR as a prognostic marker in COVID-19. 52,53 However, in our study, PLR was not found to be a significant prognostic factor of mortality in multivariable analysis, which is consistent with previous studies. 54,55 Although first reported in hepatocellular carcinoma, the prognostic value of SII has also been evaluated in other solid malignancies.…”

Plasma Levels and Renal Handling of Amino Acids Contribute to Determination of Risk of Mortality or Feed of Ventilation in Patients with COVID-19

“…Therefore, vaccination status could not interfere with our results. Some studies and reviews analyzed the predictive value of only one or two parameters, and their usefulness in predicting outcomes of COVID-19, e.g., the role of platelet/lymphocyte ratio [28], HbA 1c [29], vitamin D3 levels [30], obesity [31], d-dimer [32], lymphocyte, or neutrophil count [33]. Other studies tried to provide predictors from a more complete set of clinical markers.…”

Fever, Tachypnea, and Monocyte Distribution Width Predicts Length of Stay for Patients with COVID-19: A Pioneer Study

“…Procalcitonin (PCT) can reflect disease severity and co-infection in patients with COVID-19 [ 27 , 29 ]. Other inflammatory markers, including neutrophil-to-lymphocyte ratio (NLR) [ 30 , 31 ] and platelet-to-lymphocyte ratio (PLR) [ 31 , 32 ], were associated with the severity of COVID-19.…”