Medical costs of treating myasthenia gravis in patients who need intravenous immunoglobulin (IVIg) - a register-based study.

backgroundSeveral innovative treatments are expected for myasthenia gravis (MG) in the coming years. Healthcare payers usually require cost-effectiveness analyses before reimbursement. We aimed to investigate resource utilization and direct medical costs for patients with MG treated with intravenous immunoglobulin (IVIg) to inform such analyses.

methodsWe identified patients with MG in the Norwegian Patient Registry based on at least two hospital encounters with an MG diagnosis (ICD-10 G70.0) from 1 Jan 2010 to 31 Dec 2021. IVIg treatment was identified by medical procedure and Anatomical Therapeutic Chemical (ATC) codes (RPGM05 and J06BA02). Using Diagnosis-Related Group (DRG) cost weights, we estimated direct medical costs for each year following the first MG diagnosis.

resultsOver the study period, 1083 patients were diagnosed with MG in Norway, of whom 155 (14.3%) were treated with IVIg. No significant differences in age or sex were observed between IVIg and non-IVIg patients. Compared with non-IVIg patients, IVIg-patients had 2.3 times higher direct medical costs during the first year after MG diagnosis (EUR 35,714 vs. EUR 15,457) and 3.1 times higher costs during the second year (EUR 19,119 vs. EUR 6256). In the fifth year after diagnosis, IVIg-patients still had higher costs and resource utilization than non-IVIg patients (EUR 9953 vs. EUR 5634).

conclusionIVIg treatment represents an important marker for high direct medical costs among patients with MG. The costs continue to be high during the first five years after MG diagnosis.