VALIDATION OF THE SIMPLIFIED DISEASE ACTIVITY INDEX (SDAI) AND DAS28 AS MEASURE OF RESPONSE TO TREATMENT IN PATIENTS UNDERGOING DIFFERENT THERAPEUTIC REGIMENS

Background: SDAI is a newly established outcome measure in patients with Rheumatoid Artrhritis (RA) that can be used to quantify disease activity as well as to measure change over time (1). It has been validated in patients undergoing leflunomide as disease modifiyng antirheumatic (DMARD) therapy. Objectives: To validate SDAI in RA patients undergoing different DMARD regimens. Methods: 88 patients (F/M 72/16; Age 45±12.7; disease duration 12.4 ± 7.8; RF positivity 63/25)with active rheumatoid artrhitis (as defined by a DAS 28 >5.1) were prospectively enrolled in the study. The patients were randomly assigned to one of four groups according to the therapeutic regimens: group I: Methotrexate (MTX) 15 mg/weekly + salazopyrin 2 g/daily; group II: MTX 15 mg/weekly + infliximab 3 mg/kg at time 0, 2, 4 and every 8 weeks; group III: MTX 15 mg/weekly + etanercept 25 mg/twice weekly; group IV: MTX 15 mg/weekly + adalimumab 40 mg/every two week. SDAI and DAS28 were determined at baseline and after 6 months in each patient. Absolute and mean changes in SDAI values were compared to those detected in DAS 28. Results: SDAI and DAS 28 were found to be significantly correlated at baseline. Moreover, chenges in SDAI over time paralleled those in DAS, and were found to be significantly correlated (Table 1). Table 1 Group I 0 Group I 6 Group II 0 Group II 6 Group III 0 Group III 6 GroupIV 0 Group IV 6 DAS28 6.47±1.39 4.74±1.6 6.13±1.5 4.1±1.65 5.89±1.1 3.53±1.14 5.99±1.2 4.19±1.22 SDAI 56.9±12 35±11.8 58.9±12.9 40.8±11.4 61.6±9.96 44.8±7.20 63.8±7.5 44.7±9.11 p <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 Conclusion: SDAI is a valid measure of response to treatment in RA patients undergoing different therapeutic regimens References: 1. Rheumatol 42: 244-257; 2003