To estimate rates of exacerbation and myasthenic crisis and identify associated risk factors for crisis and repeat exacerbations among commercially-insured children with generalized myasthenia gravis (gMG) in the United States.

Clinical events in MG are costly and repeat events indicate insufficient disease management.

MG patients aged 2-17 years were identified from MarketScan® commercial insurance data (01/01/2010 to 06/30/2025) based on ≥1 inpatient or ≥2 outpatient claims (within 60-days) for MG and ≥6 months of continuous enrollment before the first qualified MG diagnosis (index date). Exacerbation and crisis rates were calculated separately for ages 2-11 and 12-17. To assess factors associated with crisis and repeat exacerbation, a nested case-control design considered patients with an event in the follow-up period as cases (corresponding event date as new case index date) and those without events as controls (date at the end of the follow-up as the new control index date). The 6-month period before the new index date was used to pre-select risk factors.

The study included 508 gMG patients (226 aged 2-11; 282 aged 12-17). Over 25% of 2-11 year-olds experienced ≥1 exacerbation and 15.5% experienced ≥1 crisis in the follow-up period; incidence rate (95% confidence interval [CI]) per 100 person-years was 18.2 (11.4–29.1) for exacerbation and 9.3 (5.1-17.1) for crisis. Among those 12-17, 34.8% and 16.7% experienced exacerbation and crisis; incidence rates 22.8 (16.9-30.1) and 7.3 (4.7-11.4). Logistic regression models found female, prior exacerbation, acetylcholinesterase inhibitors, corticosteroids, and intravenous immunoglobulin treatment as significantly associated with repeat exacerbations and crises.

Pediatric gMG patients had high rates of clinical events. Crisis and repeat exacerbation were associated with prior exacerbation and common MG treatments. This study highlights the burden of MG in this patient population and the need for improved treatments to reduce disease burden.