Fig. 8

Classification tree considering age, gender, and diagnosis and drug codes for CRGs 5424-6144-7071. The initial LDA plot shows that samples of the different CRGs appear overlapped. It may be because corresponding patients share a common chronic condition (diabetes). The absence of diagnosis code ‘401’ (hypertension) and drug code ‘C09AA’ (based on the treatment of mild-moderate hypertension) leads directly to CRG-5424, since it is the only CRG that does not consider the chronic condition EH. Furthermore, the ATC code ‘N05AL’ is the most discriminative feature for identifying CRG-7071 patients, which is the class that corresponds to patients with the highest number of chronic conditions (among the considered CRGs)