Red Cell Distribution Width (RDW), Platelets and Platelet Index MPV/PLT Ratio as Specific Time Point Predictive Variables of Survival Outcomes in COVID-19 Hospitalized Patients

Abstract

Background: COVID-19-associated coagulopathy (CAC) is a complex condition, with high rates of thrombosis, high levels of inflammation markers and hypercoagulation (increased levels of fibrinogen and D-Dimer), as well as extensive microthrombosis in the lungs and other organs of the deceased. It resembles, without being identical, other coagulation disorders such as sepsis-DIC (SIC/DIC), hemophagocyte syndrome (HPS) and thrombotic microangiopathy (TMA). Platelets (PLTs), key regulators of thrombosis, inflammation and immunity, are considered an important risk mediator in COVID-19 pathogenesis. Platelet index MPV/PLT ratio is reported in the literature as more specific in the prognosis of platelet-related systemic thrombogenicity. Studies of MPV/PLT ratio with regards to the severity of COVID-19 disease are limited, and there are no references regarding this ratio to the outcome of COVID-19 disease at specific time points of hospitalization. The aim of this study is to evaluate the relationship of COVID-19 mortality with the red cell distribution width-coefficient of variation (RDW-CV), platelets and MPV/PLT ratio parameters. Methods: Values of these parameters in 511 COVID-19 hospitalized patients were recorded (a) on admission, (b) as mean values of the 1st and 2nd week of hospitalization, (c) over the total duration of hospitalization, (d) as nadir and zenith values, and (e) at discharge. Results: As for mortality (survivors vs. deceased), statistical analysis with ROC curves showed that regarding the values of the parameters on admission, only the RDW-CV baseline was of prognostic value. Platelet parameters, absolute number and MPV/PLT ratio had predictive potential for the disease outcome only as 2nd week values. On the contrary, with regards to disease severity (mild/moderate versus severe/critical), only the MPV/PLT ratio on admission can be used for prognosis, and to a moderate degree. On multivariable logistic regression analysis, only the RDW-CV mean hospitalization value (RDW-CV mean) was an independent and prognostic variable for mortality. Regarding disease severity, the MPV/PLT ratio on admission and RDW-CV mean were independent and prognostic variables. Conclusions: RDW-CV, platelets and MPV/PLT ratio hematological parameters could be of predictive value for mortality and severity in COVID-19 disease, depending on the hospitalization timeline.

Keywords: COVID-19 disease mortality; PLT; RDW; platelet index MPV/PLT ratio; platelets; red cell distribution width; thrombogenicity index MPV/PLT ratio.

Figure A1

ROC curves for the prediction of COVID-19 outcome in relation to: LYMP # lowest (left), LYMP % lowest (center), LYMP mean (right). p-values are in reference with the 50% diagonal line.

Figure A2

ROC curve for the capability of mean CRP to predict COVID-19 disease outcome. p-value is related to the 50% reference line.

Figure A3

ROC curves for the predictive capability of DD highest (left) and DD mean (right) for COVID-19 disease outcome. p-values are in reference to the 50% diagonal line.

Figure 1

ROC curves for mean values RDW, PLTs, MPV/PLT ratio and COVID-19 disease outcome. For all cases in comparison, the comparison with the 50% diagonal line was p < 0.05.

Figure 2

ROC curves for RDW on admission (left), RDW at discharge (middle) and RDW difference (right). All curves are for the prediction of COVID-19 disease outcome. p-values are for reference with the 50% diagonal line.

Figure 3

ROC curves for the prediction of COVID-19 outcome in relation to PLT on admission (top left), PLTs 1w (top middle), PLTs 2w (top right), PLTs at discharge (bottom left) and nadir PLTs (bottom right). p-values are for reference with the 50% diagonal line.

Figure 4

ROC curves for the prediction of COVID-19 outcome in relation to MPV/PLT ratio admission (top left), MPV/PLT ratio 1w (top right), MPV/PLT ratio 2w (bottom left), MPV/PLT ratio exit (bottom right). All p-values are in reference with the 50% diagonal line.

Figure 5

ROC curves for the predictive capability of RDW on admission (left), RDW mean (middle), PLTs on admission (right) for disease severity. p-values are in reference to the 50% diagonal line.

Figure 6

ROC curves for disease severity prediction of admission MPV/PLT ratio (left), MPV/PLT ratio 1w (center) and mean value of MPV/PLT ratio (right). p-values are in reference to the 50% diagonal line.