Figure. 2From: Risk factors for severe COVID-19 in middle-aged patients without comorbidities: a multicentre retrospective studyROC curve analysis using the NLR, D-dimer, combined index and SOFA for predicting severe COVID-19 in middle-aged (40–59 years) patients without comorbidities. COVID-19 coronavirus disease 2019, AUC area under the curve, CI confidence interval, NLR neutrophil to lymphocyte ratio, SOFA Sequential Organ Failure Assessment, Combined index combined NLR and D-dimer > 1 μg/ml indexBack to article page