Leukemia & Myeloid Disorders
Epidemiology and Treatment Patterns of Idiopathic Multicentric Castleman Disease in the Era of IL-6-Directed Therapy
The epidemiology of human herpesvirus-8-negative/idiopathic multicentric Castleman disease (iMCD) remains incompletely understood. Prior epidemiologic studies of CD and iMCD have been hampered by difficulties in accurate case ascertainment resulting from a lack of uniform diagnostic criteria and a disease-specific International Classification of Diseases (ICD) code. In this study, we provide reliable estimates of CD and iMCD in the United States using a novel claims-based algorithm that includes a CD-specific ICD (10th revision) diagnosis code (D47.Z2) supported by the presence of ≥2 claims codes corresponding to the minor criteria from the international evidence-based diagnostic criteria for iMCD.
Treatment Switching Patterns in Patients with iMCD
No treatment cohort refers to patients who had no claims for iMCD-directed treatments.
Limited data exist regarding the epidemiology and treatment patterns of iMCD, and CD more generally, in the United States, particularly among patients receiving care in nonacademic settings. Administrative claims databases are valuable epidemiologic tools for studying natural history and treatment outcomes of rare diseases in the real-world setting, but the ability to do this for iMCD has previously been precluded by nonspecific diagnostic coding. Our study using a novel administrative claims–based methodology provides the most up-to-date population estimates of the incidence and prevalence of CD and iMCD in the United States and sheds light on the treatment landscape of this rare disease. Our findings highlight significant treatment gaps for patients with iMCD, a large unmet treatment need for IL-6–directed therapies, and poor adherence to treatment guidelines; the reasons for these findings must be further investigated.