Rheumatoid Arthritis disease activity assessment in routine care: performance of the most widely used composite disease activity indices and patient-reported outcome measures Comparison of disease activity indices in RA

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fausto salaffi
Marco Di Carlo
Sonia Farah
Daniela Marotto
Fabiola Atzeni
Piercarlo Sarzi-Puttini


rheumatoid arthritis, disease activity, composite disease activity indices, patient-reported outcome measures, tight control


Objective. To evaluate the convergent and discriminative validity of many continuous composite disease activity indices and patient-reported outcome measures (PROMs) in rheumatoid arthritis (RA).

Methods. RA patients with moderate or high disease activity completed five composite disease activity indices, the 28-joint Disease Activity Score – erythrocyte sedimentation rate (DAS28-ESR), the Simplified Disease Activity Index (SDAI), the Clinical DAI (CDAI), the Chronic Arthritis Systemic Index (CASI), and the Mean Overall Index for RA (MOI-RA), and five PROMs, the Patients’ Activity Scale (PAS), the Rheumatoid Arthritis Impact of Disease (RAID), the 5-item RA Disease Activity Index (RADAI-5), the Routine Assessment of Patient Index Data (RAPID3), and the Clinical Arthritis Activity (PRO-CLARA). Spearman’s was determined to assess their convergent validity, and discriminative performance was calculated by the area under the receiver-operating curve (AUC-ROC). The patients’ opinion of their symptomatic status (PASS) was used as the external criterion.

Results. The indices all showed a significant correlation (p< 0.0001 for all). Among the composite disease activity indices, the CDAI was the one that showed the best discriminating ability compared to the PASS (AUC = 0.962), while among the PROMs the RAID was the most performing (AUC = 0.879).

Conclusions. CDAI and RAID accurately reflect disease activity, clearly discriminate moderate and high disease activity levels, and are feasible to use in a clinical setting. Incorporating these validated measures into a practice’s workflow will facilitate compliance with the guidelines for the treatment of RA and provide the necessary means of treating to target.


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