Epidemiology and 10-year clinical care of juvenile myasthenia gravis in England: a retrospective cohort study

Background: Published evidence is limited on the clinical burden of juvenile myasthenia gravis (JMG). We aimed to assess epidemiology and the clinical characteristics of JMG in England. Methods: We performed a retrospective analysis of patients with newly diagnosed JMG identified in England via primary care and hospital data between 2010 and 2019. Results: 32 children (aged 2-17 years) with newly diagnosed JMG were included. Prevalence of JMG ranged from 2.2 (95% CI 1.5 to 3.1) in 2012 to 2.5 (95% CI 1.8 to 3.4) per 100 000 in 2018. The annual incidence ranged from 0.8 (95% CI 0.1 to 5.7) in 2015 to 3.8 (95% CI 1.6 to 9.0) per million per year in 2017. Incidence fluctuated in females from 1.6 (95% CI 0.2 to 11.3) in 2016 to 6 (95% CI 2.3 to 16.1) per million per year in 2018. Overall, 20 patients received first acetylcholinesterase inhibitors or corticosteroids with no prior therapy during the study period. During the follow-up period (median, 3.3 years), 17 patients (53.1%) with JMG experienced a hospitalisation. No deaths were observed. Conclusions: This study confirms the rarity of JMG in England, with steady incidence and prevalence rates over a decade. Further research is required to assess unmet needs in JMG therapy and the importance of effective treatments for this condition.