Patient-reported measures can quickly provide assessments of rheumatoid arthritis (RA) disease activity in the office setting and do not require a laboratory test or physician examination. The goal of our study was to establish the validity of patient-reported indices compared to the C-reactive protein-based Disease Activity Score (DAS28-CRP4).
Baseline and 1-year followup DAS28-CRP4 data were obtained from 740 RA subjects and were compared to indices (MDHAQ, CDAI, RAPID, RADAI, GAS) according to cyclic citrullinated peptide (CCP) status and change at 1 year. Pairwise correlations were calculated for each index.
Among 740 subjects, mean age 57 years, disease duration 14 years, the CDAI (r = 0.84, Δ r = 0.80) and RAPID (r = 0.71, Δ r = 0.70) had the highest correlation with the DAS28-CRP4 scores at baseline and 1 year. These correlations were not influenced by CCP status, disease-modifying antirheumatic drug use, biologic use, or by disease duration.
In RA, the CDAI and RAPID correlated well with the DAS28-CRP4. They may both be practical and informative in the care of patients in the office setting.