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

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.

Role of red blood cell distribution width, as a prognostic indicator in COVID-19: A systematic review and meta-analysis.

The red blood cell distribution width (RDW), an indicator of anisocytosis has emerged as a potential tool for risk stratification of critically ill patients with sepsis. Prognostic predictors are of paramount interest for prompt intervention and optimal utilization of the healthcare system in this ongoing context of the Coronavirus Disease 2019 (COVID-19) pandemic. The current systematic review and meta-analysis aims to explore the utility of RDW in the prognosis of COVID-19 patients. A comprehensive screening of electronic databases was performed up to 30th April 2021 after enrolling in PROSPERO (CRD42020206685). Observational studies or interventional studies, evaluating the impact of RDW in COVID-19 outcomes (mortality and severity) are included in this meta-analysis.Our search retrieved 25 studies, with a total of 18,392 and 3,446 COVID-19 patients for mortality and disease severity outcomes. Deceased and critically ill patients had higher RDW levels on admission in comparison to survivors and non-severe patients (SMD = 0.46; 95%CI 0.31-0.71; I2  = 88% and SMD = 0.46; 95%CI 0.26-0.67; I2  = 60%, respectively). In a sub-group analysis of 2,980 patients, RDW > 14.5 has been associated with increased risk of mortality (OR = 2.73; 95%CI 1.96-3.82; I2  = 56%). However, the evidences is of low quality. A higher level of RDW on admission in COVID-19 patients is associated with increased morbidity and mortality. However, further studies regarding the cut-off value of RDW are the need of the hour.