Evolution of cost structures in rheumatoid arthritis over the past decade.

Objective: To estimate the changes in direct and indirect costs induced by patients with rheumatoid arthritis (RA) in German rheumatology, between 2002 and 2011. To examine the impact of functional status on various cost domains. To compare the direct costs incurred by patients at working age (18-64 years) to patients at an age of retirement (≥65 years).

Methods: We analysed data from the National Database of the German Collaborative Arthritis Centres with about 3400 patients each year. Costs were calculated using fixed prices as well as annually updated cost factors. Indirect costs were calculated using the human capital as well as the friction cost approaches.

Results: There was a considerable increase in direct costs: from €4914 to €8206 in patients aged 18-64, and from €4100 to €6221 in those aged ≥65, attributable to increasing prescription of biologic agents (18-64 years from 5.6% to 31.2%, ≥65 years from 2.8% to 19.2%). This was accompanied by decreasing inpatient treatment expenses and indirect costs due to sick leave and work disability. The total growth of cost, on average, was €2437-2981 for patients at working age, and €2121 for patients at retirement age.

Conclusions: The increase in treatment costs for RA over the last decade was associated with lower hospitalisation rates, better functional status and a lower incidence of work disability, offsetting a large proportion of risen drug costs. Since the rise in drug costs has manifested a plateau from 2009 onwards, no relevant further increase in total costs for patients with RA treated in German rheumatology is expected.