Correlation of patient-reported routine assessment of patient index data with clinical measures of disease activity in psoriatic arthritis

Aim A treat-to-target strategy is recommended for management of psoriatic arthritis (PsA), although there is lack of agreement regarding the best measure of disease activity to target. Physician assessments included in traditional indices can be complex and time consuming to complete and cannot be readily conducted by telehealth. This study compares the routine assessment of patient index data 3 (RAPID3), an efficient tool comprising patient self-assessment, with traditional clinician-led composite measures in the PsA clinic setting. Methods Data were collected prospectively from July 2016 to March 2020 in 2 dedicated PsA clinics in Sydney, Australia. A receiver operating characteristic (ROC) curve was created for comparison of RAPID3 score with composite scores minimal disease activity (MDA), very low disease activity (VLDA) and disease activity in psoriatic arthritis (DAPSA) in low disease activity or remission. Results Ninety-three patients had simultaneous collection of RAPID3 and MDA measures. Mean (SD) age was 49.9 (13.5) years, 50.5% were male and 23 (24.7%) had erosive disease at baseline. RAPID3 scores <= 3.2 and <= 2.7 (range 0-30) had high sensitivity and specificity for VLDA and DAPSA remission respectively, with ROC curve area under the curve (95% CI) of 0.94 (0.91-0.97) and 0.96 (0.93-0.99). Conclusion RAPID3 has good agreement with 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, for example telehealth.