Disease burden of myasthenia gravis in relation to oral corticosteroid dose: an insurance claims database study in Japan

Introduction: Oral corticosteroids (OCS) are used for maintenance treatment of myasthenia gravis (MG). Prolonged use of higher-dose OCS may provoke serious adverse events. Therefore, Japanese clinical guidelines recommend an OCS dose target of ≤5 mg/day. This retrospective study aimed to compare the burden of MG between patients achieving this target and non-achievers. Methods: Data were obtained from three Japanese healthcare databases (JMDC, NHI and LSEHS) between 2014 and 2021. Patients with MG starting immunotherapy were enrolled and data were collected over 2 years following start of immunotherapy. Exposure to OCS was determined from medication delivery records; achievers and non-achievers of the ≤5 mg/day target during follow-up were identified. Outcomes evaluated were confirmed incident diabetes, new osteoporotic fracture, and total and MG-related costs. Results: ≤ 0.01) than in non-achievers. Discussion: OCS dose target non-achievers carry a higher burden than achievers. Broader implementation of effective treatment strategies is required to reduce long-term use of higher-dose OCS and the associated burden.