Characteristics of patients with Wilson disease in the United States: An insurance claims database study

BACKGROUND Wilson disease (WD) is a progressive, potentially fatal degenerative disease affecting the liver and central nervous system. Given its low prevalence, collecting data on large cohorts of patients with WD is challenging. Comprehensive insurance claims databases provide powerful tools to collect retrospective data on large numbers of patients with rare diseases. AIM To describe patients with WD in the United States, their treatment and clinical outcome, using a large insurance claims database. METHODS This retrospective, longitudinal study was performed in the Clarivate Real-World Data Product database. All patients with ≥ 2 claims associated with an International Classification of Diseases 10 (ICD-10) diagnostic code for WD (E83.01) between 2016 and 2021 were included and followed until death or study end. Patients were divided into two groups by whether or not they were documented to have received a specific treatment for WD. Clinical manifestations, hospitalisations, liver transplantation and death were documented. RESULTS Overall, 5376 patients with an ICD-10 diagnostic code for WD were identified. The mean age at inclusion was 41.2 years and 52.0% were men. A specific WD treatment was documented for 885 patients (15.1%), although the number of patients taking zinc salts may be underestimated due to over the counter purchase. At inclusion, the mean age of patients with a documented treatment was 36.6 ± 17.8 years vs 42.2 ± 19.6 years in those without a documented treatment. During follow-up, 273 patients (5.1%) died. Compared with the American general population, the standardised mortality ratio was 2.19. The proportion of patients with a documented WD-specific treatment who died during follow-up was 4.0% and the mean age at death 52.7 years. CONCLUSION Patients treated for WD in the United States had an excess early mortality compared with the American population. These findings indicate that there is a significant unmet need for effective treatment for WD in the United States.