Performance of routine assessment of patient index data 3 (RAPID3) in monitoring disease activity of Chinese rheumatoid arthritis patients

Aim To explore the performance of routine assessment of patient index data 3 (RAPID3) in reflecting disease activity in Chinese rheumatoid arthritis (RA) patients. Method The clinical data of 189 consecutive RA patients, including RAPID3 questionnaire, Disease Activity Score based on 28-joint count (DAS28), clinical disease activity index (CDAI) and simplified disease activity index (SDAI), and ultrasonography of hand and wrist joints were collected. The consistency between RAPID3 and DAS28, CDAI, SDAI in RA patients with different disease activities was performed by Spearman's correlations, kappa and/or weighted kappa coefficients. Result RAPID3 score was significantly associated with DAS28 and erythrocyte sedimentation rate (ESR), DAS28 with C-reactive protein (CRP), CDAI, SDAI (r = 0.797, 0.786, 0.784, and 0.760 respectively, P < 0.001 for all). RAPID3 was also significantly correlated with tender joint count, swollen joint count, ESR and CRP. The agreement of RAPID3 with DAS28 scoring systems was better in patients with moderate/high disease activity than those in remission/low disease activity. Ultrasonographic subclinical synovitis was presented in 42.3%-48.6% of patients in remission/low disease activity defined by various scoring criteria including RAPID3 with no significant difference observed (P = 0.22, >0.05). Conclusion RAPID3 showed good correlation with DAS28 scoring systems, especially in patients with moderate/high disease activity. RAPID3 is a reliable and convenient tool to monitor disease activity.