A cohort of adults with gMG was selected from Optum’s de-identified Clinformatics® Data Mart Database (01/2017-03/2023) using diagnoses (ICD-10-CM G70.0x) and physician specialty. A non-gMG control cohort was randomly selected based on similar distribution of index dates to the gMG cohort. Inverse probability treatment weights (IPTW) were calculated to balance baseline characteristics between cohorts. Weighted per-patient-per-month (PPPM) and annual all-cause total and component healthcare costs were reported in the year post-index. Costs were reported for gMG patients with and without exacerbation(s) (hospitalization with MG as an admitting diagnosis) and with and without myasthenic crisis (exacerbation including ICU service, except for surgical purposes).

After IPTW, the gMG cohort (n=15,330) and non-gMG controls (n=106,232) were well-balanced (standardized differences <10% for most baseline characteristics). Total weighted PPPM costs for gMG and non-MG cohorts were $5420 vs $1298, respectively (mean difference $4123); inpatient costs were the main driver ($2512 vs $512 [mean difference $2000]). Among gMG patients who experienced any exacerbation vs those with none, total PPPM costs were $17,113 vs $3678 (mean difference $13,435). Among gMG patients who experienced any crisis vs those with none, total PPPM costs were $18,640 vs $4531 (mean difference $14,109). The annualized cost for patients experiencing MG exacerbation or crisis totaled $205,356 and $223,680, respectively.