Treatment Patterns in Patients with Late-Onset Myasthenia Gravis in Japan: An Insurance Claims Database Study

BACKGROUND AND OBJECTIVE: This study evaluated treatment patterns and oral corticosteroid (OCS) use in Japanese patients with myasthenia gravis, comparing late-onset (mean age 79.8 years) and early/adult-onset (mean age 61.3 years) cohorts. It also explored treatment frequency rates. METHODS: We conducted a retrospective analysis of the DeSC Healthcare claims database (2014-21). Adults with myasthenia gravis starting immunosuppressant therapy and with ≥ 2 years of follow-up were included. Patients were stratified by age group (< 75 and ≥ 75 years) and by exposure to early fast-acting treatment (EFT). Outcomes included OCS dose trajectories, time to achieve a maintenance dose of ≤ 5 mg/day, and the frequency of myasthenia gravis cases treated with immunotherapy. RESULTS: Early fast-acting treatment use was lower in the late-onset cohort (31/148 patients; 20.9%) than in the early-onset cohort (42/180; 28.0%). Initial and maximum OCS doses and time spent > 20 mg/day tended to be lower in late-onset patients. The OCS target was achieved more often and sooner in late-onset patients (median 5.1 vs 14.9 months), particularly in those without EFT. The frequency of treated myasthenia gravis cases was higher in late-onset patients (7.09 vs 3.97 per 100,000). CONCLUSIONS: Late-onset patients were less likely to receive EFT, received lower OCS doses yet reached the OCS target earlier, which may reflect physician caution with OCS exposure and good response to treatments. The findings highlight timely identification of the need for EFT, safer OCS-sparing strategies, and clearer clinical guidance in patients with late-onset myasthenia gravis.