Epidemiology of myasthenia gravis in France: A retrospective claims database study (STAMINA)

•We found a higher incidence and prevalence of MG are higher than previously reported in most European countries.•AChEIs are the most common treatment and more aggressive treatments (thymectomy, IVIg, azathioprine, plasma exchange, mycophenolate mofetil, cyclophosphamide, and rituximab) are mainly used the first year of the disease history.•Despite the availability of several treatments, patients with MG still experience exacerbations and crises and have an excess mortality compared to controls without MG, regardless of comorbidities. The objectives of this observational study were to report the incidence and prevalence of myasthenia gravis (MG) in France, describe patients’ characteristics and treatment patterns, and estimate mortality. A historical cohort analysis was performed using the French National Health Data System (SNDS) database between 2008 and 2020. Patients with MG were identified based on ICD-10 codes during hospitalization and/or long-term disease (ALD) status, which leads to a 100% reimbursement for healthcare expenses related to MG. The study population was matched to a control group based on age, sex and region of residence. The overall incidence of MG was estimated at 2.5/100,000 in 2019 and the overall prevalence at 34.2/100,000. The mean age was 58.3 years for incident patients and 58.6 for prevalent patients. Among patients with MG, 57.1% were women. In the first year after identification of MG, acetylcholinesterase inhibitors were the most commonly used treatments (87.0%). Corticosteroids were delivered to 58.3% of patients, intravenous immunoglobulin to 34.4%, and azathioprine to 29.9%. Additionally, 8% of patients underwent thymectomy. The proportions of patients with exacerbations and crises were 59.7% and 13.5% respectively in the first year after MG identification. All-cause mortality was significantly higher in patients with MG compared to matched controls (HR=1.82 (95% CI [1.74;1.90], P