Characteristics of Patients with Myasthenia Gravis in the French Rare Disease Registry

The French National Rare Diseases Registry (BNDMR) was established in 2007 to ensure access to optimal care standards for all patients with rare diseases in dedicated reference centres. The objective of this retrospective cohort study was to describe patients with myasthenia gravis (MG) in the BNDMR.

All patients aged ≥ 18 years in the BNDMR with a confirmed diagnosis of MG visiting a reference centre at least once between 2007 and 2021 (inclusive) were included. Diagnosis was defined through ORPHA:589 or ORPHA:391490 disease codes. Patients were followed for ≥ 12 months until 31 December 2022 (or until death). Data were collected on demographics and disease history. Mortality was estimated using Kaplan-Meier survival analysis. Healthcare resource utilisation at the reference centre was documented.

Overall, 3963 patients were analysed. Mean follow-up duration was 6.1 ± 3.8 years. The median interval between diagnosis and inclusion was 3.8 months [IQR: 1.5-7.5] and the median age at symptom onset was 52.0 [IQR: 34.0-69.0] years. Survival probability was 82.7% at 10 years, and higher in women than men (p < 0.001; logrank test). The mean interval between visits was 4.1 months. The mean number of overnight or day hospitalisations per patient was 2.6 ± 3.4 and the mean number of physician consultations per patient per year was 1.7 ± 1.1.

This national registry study provides reference data for patients in France with a confirmed diagnosis of MG. However, all patients with MG are still not managed in dedicated reference centres.