Only 5 strong predictors remained in the prediction model when the λ of LASSO regression was 0.0415, i.e., presence of diabetes mellitus and chills, neutrophil percentage > 75%, initial CRP level of 50–100 mg/L, and procalcitonin > 0.3 ng/mL within 24 h after admission (Additional file 1: Fig. S2). This evidence concerns the gene CRP and diabetes mellitus.