An index of only patient-reported outcome measures, routine assessment of patient index data 3 (RAPID3), in two abatacept clinical trials: similar results to disease activity score (DAS28) and other RAPID indices that include physician-reported measures.

Objectives: To analyse the capacity of routine assessment of patient index data 3 (RAPID3), an index of only the three patient-reported outcome (PRO) measures in the RA Core Data Set-physical function, pain and global status-to distinguish abatacept from control treatments in two clinical trials, and to compare RAPID3 results with the disease activity score 28 (DAS28) and RAPID-based indices that add a tender or swollen joint count and/or physician/assessor global estimate of status.

Methods: Clinical trial data from AIM (Abatacept in Inadequate response to Methotrexate) and ATTAIN [Abatacept Trial in Treatment of Anti-tumor necrosis factor (anti-TNF) INadequate responders] were reanalysed. Mean values were computed at baseline, endpoint and for change between baseline and endpoint for RAPID3, DAS28 and additional RAPID indices to study whether they had greater capacity to distinguish abatacept from control therapy. RAPID4TJC adds to RAPID3 a tender joint count; RAPID4SJC, a swollen joint count; RAPID4MD, a physician/assessor global estimate; and RAPID5 adds both a tender joint count and physician/assessor global estimate. RAPID2 includes only physician/assessor and patient global estimates.

Results: All indices indicated significant differences of 19-28% between abatacept and control groups. Results were similar for RAPID3 of only patient measures, compared to DAS28 and other RAPID-based indices.

Conclusion: A RAPID3 'patient-only' index, without a joint count or any measure from a health professional or laboratory, distinguishes active from control treatments in two abatacept clinical trials, at levels similar to DAS28 and to other RAPID-based indices that add physician-reported measures.