To assess the incremental healthcare costs associated with generalized myasthenia gravis (gMG) in commercially insured children.

gMG is a rare autoimmune disease associated with high healthcare resource utilization and costs among adults. Data on pediatric patients remain limited.

Using MarketScan® data (01/01/2010–06/30/2025), we identified a retrospective cohort of patients aged 2–17 with ≥1 inpatient or ≥2 outpatient MG diagnosis codes within 60 days and ≥6 months of continuous commercial insurance enrollment before the first qualifying MG diagnosis (index date). Controls (non-MG) were selected randomly. Patients were followed until disenrollment, death, or end of data. Costs were compared between cohorts using inverse probability of treatment weighting to adjust for baseline characteristics. Subgroup analyses evaluated costs among gMG patients experiencing exacerbation or crisis.

A total of 508 gMG (66% female; mean age 11.3 years) and 5178 non-MG patients were identified. Weighted cohorts were well-balanced. Mean total healthcare costs per-patient-per-month (PPPM) were $6295 vs $226 for gMG vs controls (mean difference $6069; 95% confidence interval $4681-7457). Inpatient and outpatient ((unrelated to office visits) costs were the primary drivers of total costs for gMG cases vs controls inpatient: $2872 vs $27 ($2844; $1819-$3870); outpatient $2568 vs $84 ($2483; $1860-$3107) PPPM, respectively. Immunoglobulin therapies alone accounted for 48% of outpatient costs Weighted analysis of MG patients experiencing exacerbation or crisis vs those who did not experience such events revealed total costs of $14,154 vs $3378 PPPM ($10,776; $6575-$14,976) for patients with vs without exacerbation and $16,474 vs $4684 PPPM ($11,790; $5063-$18,518) for patients with vs without crisis.

Pediatric gMG patients had higher healthcare costs than non-gMG patients. Patients with MG exacerbations and crises had approximately 4 times higher costs vs gMG patients without such events, highlighting the need for improved treatments to reduce the frequency of costly events.