Objective: To evaluate the therapeutic and economic consequences of various disease activity indices (DAIs) in RA according to 1987 and 2010 criteria. Methods: Data on disease activity states from all sustained visits were assessed from all patients who participate in the treatment in the Rotterdam Early Arthritis Cohort (tREACH) study, a stratified randomized trial to evaluate different treatment strategies in patients with a symptom duration of <1 year. Frequencies of treatment adaptations, based upon exclusive thresholds of various DAIs, were visualized in reclassification tables. The Stuart-Maxwell test was applied to analyse any significant differences between treatment decisions according to the different DAIs. Simulated annual median medication costs were estimated using the tREACH medication protocol with standard national costs.Results. DAIs perform similar in RA according to 1987 and 2010 criteria. A total of 1104 DASs per DAI were available from 296 patients. DAIs differ significantly, compared with DASs, in classifying a patient's disease state. Consequently, treatment intensifications occur more frequently with SDAI, CDAI and DAS-28 usage, compared with DAS. Tapering treatment occurs less frequently with SDAI and CDAI and more frequently with DAS-28 usage. Simulated annual median medication costs are significantly higher if DAS-28, SDAI and CDAI are used compared with DAS usage.Conclusion. Usage of various DAIs in a single patient leads to inconsistent disease state categorizations. Consequently, these inconsistencies significantly influence therapeutic decisions and accompanying costs. As DAI usage is imperative to uphold current European League Against Rheumatology (EULAR) treatment recommendations, physicians should consider these therapeutic and economic consequences before choosing a particular DAI.

Disease activity, Rheumatoid arthritis
dx.doi.org/10.1093/rheumatology/kes008, hdl.handle.net/1765/63478
Rheumatology (Oxford, England)

de Jong, P.H.P, Hazes, J.M.W, van Zeben, D, van der Lubbe, P.A, de Jager, M.H, de Sonnaville, P.B.J, … Weel, A.E.A.M. (2012). Treatment decisions and related costs differ significantly depending on the choice of a disease activity index in RA, according to 1987 and 2010 classification criteria. Rheumatology (Oxford, England), 51(7), 1269–1277. doi:10.1093/rheumatology/kes008