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 January 2017-31 March 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 3748 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 ($1298 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.