Correlation between rapid-3, DAS28, CDAI and SDAI as a measure of disease activity in a cohort of Colombian patients with rheumatoid arthritis

The objective of this study is to correlate the patient-driven tool Routine Assessment of Patient Index Data 3 (RAPID-3) with other common tools used in daily practice to measure disease activity in rheumatoid arthritis (RA).One hundred nineteen RA patients according to 1987 American College of Rheumatology criteria who consecutively attended a RA outpatient clinic between August and December 2015 were evaluated. Data was stored in an electronic form that included demographic information, comorbidities, concomitant medication, and laboratory results. The disease activity was determined by tender and swollen joint count, pain and disease activity visual analog scales (VAS), disease activity score 28 (DAS28), Clinical Disease Activity Index (CDAI), Simplified Disease Activity Index (SDAI), and multidimensional health assessment questionnaire (MDHAQ). Correlations between RAPID-3 and other disease activity tools were assessed. Mean age was 61 ± 13.8 years with a median disease duration of 14 years (IQR 5–21), 77% were females. Median scores were MDHAQ 0.5 (IQR 0.1–1.2), DAS 28 3.8 (IQR 2.7–5.1), and RAPID-3 12.3 (IQR 6–19). A strong correlation was obtained between RAPID-3 and DAS 28 (r 0.719, p < 0.001), CDAI (r 0.752, p < 0.001), and SDAI (r 0.758, p < 0.001). RAPID-3 had a high correlation with tools regularly used for disease activity assessment of RA patients in daily practice. The ease of its application favors routine use as it does not require laboratory results and joint counts.