Introduction
A treat-to-target strategy is recommended for management of psoriatic arthritis (PsA)1,2, though there is lack of agreement regarding the best measure of disease activity to target3. Complex composite measures take time in busy clinical settings4 and are not possible with telemedicine. The Routine Assessment of Patient Index Data 3 (RAPID3)5 is an efficient score combining patient reported function, pain and global health. This study compares the RAPID3 with clinician-led composite measures in the PsA clinic setting.
Methods
Data was collected prospectively from psoriatic arthritis clinics at Concord Hospital and Liverpool Hospital, Sydney, between July 2016 and March 2020. A receiver operator curve (ROC) was created for comparison of RAPID3 score with each of the clinical disease activity measures Minimal Disease activity (MDA), Very Low Disease Activity (VLDA)6 and Disease Activity in Psoriatic Arthritis (DAPSA)7 in low disease activity (DAPSA-LDA) or remission (DAPSA-REM). Area Under the Curve (AUC) was calculated for each ROC, with 1 representing perfect accuracy.
Results
Ninety-three patients had simultaneous collection of RAPID3 and MDA/VLDA measures over 336 clinic visits. Eighty-five patients had simultaneous collection of RAPID3 and DAPSA measures over 290 clinic visits. The mean (SD) age was 49.9 (13.5) years and 47 (50.5%) were male. MDA and VLDA criteria were met on 81 (24.1%) and 24 (7.1%) occasions respectively, whereas DAPSA-LDA and DAPSA-REM criteria were met on 110 (37.9%) and 38 (13.1%) visits respectively. ROCs demonstrated AUC (95% CI) of 0.910 (0.868 - 0.952), 0.937 (0.905 - 0.969), 0.903 (0.867 - 0.938) and 0.960 (0.933 - 0.987) for MDA, VLDA, DAPSA-LDA and DAPSA-REM respectively.
Conclusion
In cross-sectional analysis, RAPID3 has good agreement with the physician-led composite scores of MDA, VLDA and DAPSA, and provides a viable alternative to composite scores. This is particularly helpful in settings that do not allow for clinical examination.