Health care utilisation and economic burden of difficult-to-treat rheumatoid arthritis: a cost-of-illness study.

OBJECTIVES To determine the impact of difficult-to-treat rheumatoid arthritis (D2T RA) on (costs related to) health care utilisation, other resource use and work productivity. METHODS Data regarding health care utilisation, other resource use and work productivity of 52 D2T (according to the EULAR definition) and 100 non-D2T RA patients were collected via a questionnaire and an electronic patient record review during a study visit. Annual costs were calculated and compared between groups. Multivariable linear regression analysis was performed to assess whether having D2T RA was associated with higher costs. RESULTS Mean (95% confidence interval) annual total costs were €37,605 (€27,689-50,378) for D2T and €19,217 (€15,647-22,945) for non-D2T RA patients (p < 0.001). D2T RA patients visited their rheumatologist more frequently, were more often admitted to day care facilities, underwent more laboratory tests and used more drugs (specifically tsDMARDs), compared with non-D2T RA patients (p < 0.01). In D2T RA patients, the main contributors to total costs were informal help of family and friends (28%), drugs (26%) and loss of work productivity (16%).After adjustment for physical functioning (health assessment questionnaire (HAQ)), having D2T RA was no longer statistically significantly associated with higher total costs. HAQ was the only independent determinant of higher costs in multivariable analysis. CONCLUSIONS The economic burden of D2T RA is significantly higher than that of non-D2T RA, indicated by higher health care utilisation and higher annual total costs. Functional disability is a key determinant of higher costs in RA.