New approaches to the assessment of rheumatoid arthritis activity: Simplified Disease Activity Index (SDAI) TOC \o "1-5" \h \z in early arthritis

Abstract

Objective. To assess significance of Simplified Disease Activity Index (SDAI) in early arthritis. Material and methods . 76 pts with suspicion of rheumatoid arthritis (RA), duration of the disease less than 6 months (3,6±1,7 months), meanage48,5±14years(17-76years)and male/female ratio 1/5 were examined. DAS 28 and SDAI were calculated for complex assessment of arthritis activity. Results. Mean SDAI value was 28,9±14,9 (1,37-67,64). In 40 (52,1%) of pts it corresponded to moderate, in 20 (26,6%) - to low and in 16 (21,3%) - to high activity of RA. Mean DAS 28 value was 4,86+1,23 (2,31-6,92). 12,5% of pts had low, 40,3% - moderate and 47,2% - high activity. SDAI significantly correlated with DAS 28 (p<0,0001). Functional status examination showed mean HAQ value 0,82±0,62(0-2,5). HAQ correlated with SDAI and DAS 28 (p<0,005). In 37 from 76 pts (48,7%) RA was diagnosed according to ACR 1987 criteria. In 39 (51,3%) of pts the diagnosis was not verified and they were considered as having undifferentiated arthritis (UDA). SDAI values in RA were significantly higher than in UDA (33,1±I5,9 and 24,5+12,3 respectively, p<0,05). Similar differences were shown for DAS 28 (4,72±1,1 in RAand 2,9±0,7 in UDA, p<0,05. 30,8% of RA pts had low, 48,7% - moderate and 20,5% - high inflammatory activity according to SDAI. In UDA low and moderate activity were more frequent (59,5% and 32,4% respectively) than in RA. DAS 28 and SDAI activity stages completely coincided neither in RA nor in UDA pts. Conclusion. SDAI is a sensitive method of activity assessment and correlates with DAS and HAQ not only in definite long standing RA that was shown at validation of this index but also in early arthritis.

Keywords

• rheumatoid arthritis
• undifferentiated arthritis
• simplified disease activity index