Comparison of Disease Activity Score in 28 joints with ESR (DAS28), Clinical Disease Activity Index (CDAI), Health Assessment Questionnaire Disability Index (HAQ-DI) & Routine Assessment of Patient Index Data with 3 measures (RAPID3) for assessing disease activity in patients with rheumatoid arthritis at initial presentation

BACKGROUND & OBJECTIVES: In patients with rheumatoid arthritis (RA), disease severity assessment is done using Disease Activity Score in 28 joints with ESR (DAS28). Computing DAS28 is time-consuming, requires laboratory testing and an online calculator. There is a need to validate rapid methods of disease severity assessment for routine daily use. This study was conducted to compare DAS28, Clinical Disease Activity Index (CDAI), Health Assessment Questionnaire Disability Index (HAQ-DI) and Routine Assessment of Patient Index Data with 3 measures (RAPID3) to assess the disease activity in patients with RA. METHODS: We prospectively studied the utility of CDAI, HAQ-DI and RAPID3 scoring in 100 consecutive newly diagnosed, disease modifying antirheumatic drugs (DMARDs) naïve adult patients with RA seen during January 2013 and June 2014 at a tertiary care teaching hospital in south India. RESULTS: The mean age of the patients was 42.1±11.6 yr, there were 82 females. The median [interquartile range (IQR)] symptom duration was 6 (range 4-12) months. The median (IQR) DAS28, CDAI, HAQ-DI and RAPID3 scores at presentation were 7 (6-7), 36 (28-43), 2 (1-2) and 17 (13-19), respectively. A significant positive correlation was observed between DAS28 and CDAI (r=0.568; P<0.001); DAS28 and HAQ-DI (r=0.304; P=0.002) and DAS28 and RAPID3 (r=0.404; P<0.001). A ‘slight-to-fair’ agreement was observed in between DAS28 and CDAI (kappa-statistic=0.296). The agreement between DAS28 and HAQ-DI (kappa-statistic=0.007) and RAPID3 (kappa-statistic=0.072) was less robust. INTERPRETATION & CONCLUSIONS: In adult patients with RA, in the setting where illiteracy is high, CDAI emerged as the preferred choice for rapid assessment of severity of disease at the time of initial presentation.