Exacerbation and myasthenic crisis in generalized myasthenia gravis: real-world healthcare resource utilization and cost burden in the United States.

Objectives: Healthcare resource utilization (HCRU) and cost assessments for generalized myasthenia gravis (gMG) rarely include matched controls. HCRU and costs of acute MG-related events (MG exacerbation and myasthenic crisis) have been examined, but aggregation or comparison between studies is limited by heterogeneity. The study aim was to provide comprehensive, real-world data about gMG patients in the United States, including those experiencing MG-related events. A claims database analysis assessed (i) incremental HCRU and cost burden among adults with gMG versus non-gMG controls, (ii) occurrence of MG-related events, (iii) HCRU and cost burden of MG-related events, and (iv) factors associated with MG-related events.

Methods: In this retrospective cohort study, adults with gMG in the United States were identified from Optum's de-identified Clinformatics® Data Mart Database (1/1/2017-3/31/2023). Rates of MG-related events during follow-up were calculated. Regression models assessed associations between occurrence of MG-related events and baseline demographic/clinical variables using a nested case-control design embedded within the existing gMG cohort. Incremental HCRU and healthcare costs were compared between cohorts with/without gMG using the propensity score method with inverse probability of treatment weighting for confounding controls. Incremental HCRU and healthcare costs were also reported for gMG subgroups with/without MG-related events.

Results: Analyses included 16,561 gMG patients (12,813 prevalent and 3,748 incident) and 105,716 non-gMG controls. Among prevalent and incident gMG patients, respectively, MG exacerbation occurred during follow-up in 12.2% and 22.0% and myasthenic crisis in 6.0% and 12.4%. Patients with prior MG-related events were more likely to experience future events (odds ratio range 1.76-7.05). After weighting, gMG patients (median follow-up 696 days) experienced more frequent all-cause HCRU encounters and >4-fold higher healthcare costs ($5420 PPPM or ∼$65,000 per annum) versus non-gMG controls ($1,298 PPPM or ∼$15,500 per annum). Among MG patients, those with MG exacerbation/myasthenic crisis, respectively, experienced means of 3.02/3.35 hospitalizations, 1.91/2.13 emergency department encounters, 12.70/13.39 skilled nursing facility encounters, and 67.86/75.52 outpatient encounters during follow-up; associated costs were $17,113/$18,640 PPPM (or ∼$205,000/$224,000 per annum).

Conclusion: The total healthcare cost of gMG was higher than some previous estimates at $5420 PPPM, driven primarily by inpatient care. MG exacerbation and myasthenic crisis occurred at a notable rate, could be recurrent, and were associated with high HCRU and costs. Findings can inform treatment decision-making with the aim of improving symptom control and reducing the likelihood of MG-related acute events.