Red blood cell distribution width: a new predictor of disease severity in COVID-19 patients

Importance Coronavirus disease 2019 (COVID-19) is the main global health problem nowadays. It is the primary cause of many deaths all over the world, as well as associated with many morbidities and consumption of medical resources. Objective To assess the relation between red blood cell distribution width (RDW) level in the blood of COVID-19-infected patients on one side and various criteria of disease severity and mortality risk on the other side, to help answer the question, 'can we use RDW as a predictor of COVID-19 disease severity?' Patients and methods This study included 184 adult patients (98 males and 86 females) with positive nasopharyngeal swab for acute respiratory syndrome coronavirus 2 infection diagnosed at Mansoura University Hospitals. Patients underwent clinical, laboratory, and radiological evaluation of COVID-19 cases with close follow-up till complete cure or death. Cases were divided according to the disease severity into four groups (six mild cases, 45 moderate cases, 48 severe cases, and 85 critical cases). We compared RDW level at the time of hospitalization in the four groups. Results A highly significant difference (P%0.001) was found between mean RDW in mild and moderate groups compared with severe and critical groups. Moreover, there was a positive linear correlation between RDW level and disease severity (P%0.001). RDW level more than 13.65 could predict severe disease with 79.2% sensitivity and 66.7% specificity. RDW level more than 13.85 could predict critical disease with 78.8% sensitivity and 66.7% specificity. Mean RDW was significantly lower in cured cases compared with those died owing to COVID-19 complications (P=0.004). RDW level more than 13.95 could predict increased mortality risk, with 73.5% sensitivity and 52.5% specificity. Conclusion Higher RDW levels in COVID-19-infected patients, upon hospital admission, were associated with increased disease severity and mortality risk.