The role of Monocyte Distribution Width (MDW) in the prognosis and monitoring of COVID-19 patients

The new parameter derived from the standard deviation of the monocyte distribution width (MDW) has shown a good diagnostic efficacy in COVID-19 patients. In this study, we propose MDW as a prognostic and monitoring parameter in patients with severe forms of COVID-19. Sixty SARS-CoV-2-positive patients admitted to the San Donato Hospital in Arezzo were enrolled. A blood sample taken to measure the complete blood count was used for the determination of MDW using a UniCel DxH 900 instrument (Beckman Coulter). For each patient, a mean of 6 ± 2 measurements of MDW were taken. The difference between the last and first MDW results was reported as the ΔMDW variable. The ΔMDW and age were significantly correlated to the outcome. In non-survivors patients, the difference in the mean of the MDW between the first and other points was not significant, while in survivors, the first point was higher than the other points (p < 0.005), with the exception of the mean of the second point (p-value = NS). The ΔMDW area under the curve (AUC) was 0.84, and with a cut-off lower than 0.00 the sensitivity and specificity were 88% and 81%, respectively. The most important result of this study is the ΔMDW calculated on the basis of the difference between the first and third measurement, after approximately the 5–7th day of hospitalisation. A ΔMDW less than one was indicative of an unfavourable prognosis. The data reported suggest that MDW could be used to support monitoring and surveillance, alongside other tests such as procalcitonin, in critically ill patients in the ICU.