Direct cost-modeling of rheumatoid arthritis according to disease activity categories in France

The objective of this cost-of-illness study was to assess the use of direct medical resources, excluding drug costs, by patients with rheumatoid arthritis (RA) in France, and to construct cost estimates according to level of disease activity.

Three categories of RA disease activity were defined according to Disease Activity Score 28-joint count (DAS28) thresholds: remission (DAS28 < 2.6), low disease activity state (LDAS; i.e., DAS28 ≤ 3.2), and moderate to high disease activity (MHDAS; i.e., DAS28 > 3.2). Eight resource utilization items were defined: medical visits, laboratory tests, hospitalization, imaging, physiotherapy, nursing, adaptive aids, and transportation. Resource utilization and unit costs from the national-payer perspective were estimated through expert opinion and simulated using distribution ranges for each item. Cost distributions were computed by Monte-Carlo simulations estimating overall costs per 6 months over a 2-year period.

For patients achieving remission, costs were estimated at a mean of €771 (SD 199) for the first 6 months and at €511 (SD 162) for each subsequent 6-month period. For patients achieving LDAS, costs were estimated at €905 (SD 263) for the first 6 months and €696 (SD 240) for each subsequent 6-month period. For patients in MHDAS, costs were estimated at €1215 per 6 months (SD 405).

This cost-of-illness assessment provided current estimates of direct medical costs for RA according to disease activity in France. The findings suggest that achieving remission or LDAS is associated with substantially lower medical costs for RA versus being in MHDAS.