OBJECTIVES

The two phenotypes of ANCA-associated vasculitis (AAV), Granulomatosis with Polyangiitis (GPA) and Microscopic Polyangiitis (MPA) are rare autoimmune diseases causing necrosing of blood vessels. The annual incidences rates are 2.1-14.4 and 2.4-10.1 per million in Europe for GPA and MPA, respectively. These multisystem inflammatory diseases result in life-threatening or organ-threatening disease with an increased mortality ratio of 2.6. A study was set up to assess the therapeutic management of GPA/MPA patients and its associated economic burden in France.

METHODS

A retrospective cohort study was conducted using the French National Healthcare databases (SNDS). The study population included GPA/MPA patients identified through relevant ICD-10 codes (M313/M317) in the period 2010-2018. Induction and maintenance treatment phases were defined through algorithms built from specific treatments and validated by a group of expert clinicians. Resources utilization were considered from the National Health Insurance perspective. A Kaplan-Meier model has been used to assess survival.

RESULTS

The study cohort consisted of 6,581 GPA/MPA patients. The majority of patients had GPA only (4,445). Incident patients represented 2,605 patients, among which 1,578 were GPA only. They were aged 65 years old in median and 54.3% were men. Main treatments during induction and maintenance phases were glucocorticoids (95.5% and 98.3% for GPA and MPA, respectively), cyclophosphamide (47.6% and 0%), rituximab (18.7% and 30.9%), oral azathioprine (20.7% and 31.5%) and plasmatic exchange (21.0% and 0%). Standardized mortality rate was 2.21 in 2018. The average annual cost per GPA/MPA patient was 26,560±53,428€. The cost breakdown showed that the most important component was due to hospitalizations (61%) followed by medicines (9%).

CONCLUSIONS

This study assessed a number of GPA and MPA patients in France during a large period of time and described the evolution of therapeutic management of patients. It demonstrates the major economic burden of the two phenotypes of AAV.