The Lasso feature selection [45] (penalty = 1.0, lambda = 4.183 × 10−2) algorithm revealed the following features with high predictive performance: endotrachial intubation, 1st day respiratory rate, coexistence of metastatic cancer, albumin, systolic blood pressure, and Red Cell Distribution Width (RDW) (Appendix A, Table A2). Here, ALB is linked to metastatic malignant neoplasm.