Background: Generalized myasthenia gravis (gMG) is typically managed with long-term corticosteroid therapy, which is associated with a wide range of comorbidities, substantial economic burden, and reduced quality of life.

Objective: To assess the cost-consequence of corticosteroid-related comorbidities and estimate potential cost savings from corticosteroid discontinuation in adult patients with gMG, at the population level, from the Korean healthcare-payer perspective.

Methods: We developed a cost-consequence simulation model to estimate the impact of corticosteroid discontinuation in the gMG population. Transition probabilities and healthcare utilization data were obtained from national databases and published literature. Patients were assumed to discontinue corticosteroids. Primary outcomes included annual differences in comorbidity incidence, relative risks (RR), and direct medical costs.

Results: At the population level, model estimates suggest approximately 89 fewer cases of depression (95% CI: 75-103), 89 of hypertension (95% CI: 63-117), 69 of dyslipidemia (95% CI: 46-94) and 67 of type 2 diabetes (95% CI: 54-80) per 1000 people. The RR for pneumonia was lowest (0.29); while depression, osteoporosis, and type 2 diabetes showed nearly 50% reductions. Depression yielded the most significant economic benefit, with estimated annual overall cost savings of KRW 960 million, followed by  KRW 880 million for pneumonia, KRW 370 million for type 2 diabetes, and KRW 300 million for hypertension.

Conclusion: Reducing corticosteroid use in patients with gMG may substantially lower the clinical and economic burden of corticosteroid-related comorbidities. Further research is needed to evaluate its broader clinical, economic, and societal impact in real-world settings.