The Diagnosis of Drug-induced Liver Injury: Current Diagnostic Ability and Future Challenges of the Digestive Disease Week-Japan 2004 Scale 15 Years after Its Proposal

OBJECTIVE: This study examined whether or not the Digestive Disease Week-Japan (DDW-J) 2004 scale proposed over 15 years ago can be applied to current cases of drug-induced liver injury (DILI). METHODS: The new patients group included 125 patients from 2012 to 2019 and was divided into 2 subgroups: 96 patients in the new DILI group and 29 patients in the new non-DILI group. Similarly, the old patients group included 105 patients from 1997 to 2002 and was divided into 2 subgroups: 59 patients in the old DILI group and 46 patients in the old non-DILI group. Patients were assessed by the DDW-J 2004 scale; those with a score ≥3 were defined as having DILI. RESULTS: The total score of the new DILI group was significantly lower than that of the old DILI group [6 (1-11) vs. 6 (3-9), p=0.004]. The sensitivity, specificity, positive predictive value, and negative predictive value (NPV) were 94.8%, 65.6%, 90.1%, and 79.2%, respectively, in the new patients group and 100%, 91.4%, 93.7%, and 100%, respectively, in the old patients group. The specificity and NPV of the new patients group were significantly lower than those of the old patients group. CONCLUSION: The DDW-J 2004 scale maintains a stable diagnostic ability for DILI, regardless of differences in eras and verification methods. However, differential diagnoses can affect the scoring, and new types of DILI, such as immune-related adverse events, must be addressed. Therefore, upgrading the scale should be considered.