Presentation (CTI)

OBJECTIVES: Wilson’s disease (WD) is a rare progressive hereditary liver disease. Collecting epidemiological and clinical data from large numbers of WD patients is challenging due to its rarity. This study aimed to investigate the pertinence of different potential markers for case identification of WD patients in the French National Health Data System (SNDS).
METHODS: Patients in the SNDS with hospitalization or long-term disease (LTD) status associated with a diagnostic code for WD (E83.0) between 2009 and 2019 were identified and followed from first documentation until 31st December 2019 (or death). Four patient groups were compared. Group A: patients hospitalized for WD, but with neither LTD status nor specific WD treatment. Group B: patients with LTD status, but without WD treatment. Group C: patients hospitalized for WD with treatment, but without LTD status. Group D: patients with both LTD status and WD treatment.
RESULTS: 1,520 patients were included (Group A: N=702; Group B: N=153; Group C: N=194; Group D: N=471). >75% of patients in Groups A and B were never monitored for copper accumulation. The mean number of blood copper tests over the follow-up period was 0.30±2.47 in Group A, 0.76±2.34 in Group B, 3.05±7.66 in Group C and 5.33±7.90 in Group D. Patients in Group A frequently presented LTD status for conditions unrelated to WD and higher mortality (hazard ratio: 2.87 [95%CI: 1.87-4.41] compared to Group D), frequently dying of causes unrelated to WD.
CONCLUSIONS: Many patients with a hospitalization claim with a diagnostic code for WD never received specific treatment nor underwent copper monitoring. Substantial doubt exists whether these patients actually had WD. Validation studies, for example with linkage to national rare diseases registries including clinical data, are needed to find the optimal diagnostic algorithm to identify WD unambiguously in insurance claims databases to improve long-term value analysis.