OBJECTIVES: Myasthenia Gravis (MG) is a chronic autoimmune disease with symptoms of muscle weakness and fatiguability. The aim of this study was to estimate MG-related health care resource use (HCRU) and associated costs in France.

METHODS: Data were extracted from the French national claims database (SNDS) for the period 1/1/2008-31/12/2019.

Adult MG patients were identified using an algorithm based on the G70 ICD-10 code with/without an acetylcholinesterase inhibitor delivery.

• Incident cases were patients with a new MG diagnosis between 1/1/2012-31/12/2019.
• Prevalent cases were patients with a MG diagnosis between 1/1/2008-31/12/2019 and alive on 1/1/2019.

The incident and prevalent MG patients were compared with a control group matched on age, sex and region.

Direct costs were estimated from a societal perspective and excluded over-the-counter drugs.

A multivariable model was used to identify patient characteristics associated with higher MG costs.

RESULTS: In 2019, the total cost for the 18,921 prevalent patients was 160,942,026€ compared with 69,440,070€ in controls, which leads to an additional cost of 91,501,956€ for MG patients (48,1% for hospital cost and 51,9% for outpatient cost).

MG patients had significantly higher HCRU than controls, including consultations with physicians, nurses, physiotherapists and hospitalizations.

Aging, male, higher socioeconomic status and certain disease characteristics (treatment, crisis/exacerbation, shorter time since onset) were associated with a higher cost.

In the 11,336 incident patients, cost peaked in the first year after MG identification (17,673€ versus 4,267€ for controls), declined sharply in the second year (9,941€/3,912€), and gradually reduced thereafter (3rd year, 8,693€ versus 3,3931€; 4th year, 8,220€ versus 4,017€; 5th year, 7,461€ versus 4,008€; 6th year, 7,330€ versus 3,660€). Hospitalization costs represented 68.9% of the first-year costs, at 12,178€ per MG patient.

CONCLUSIONS: MG-associated costs in France are high, especially in the first year of the disease and are mainly driven by hospitalizations.