Search

Background CDAI and SDAI have been frequently used to categorize disease activity in patients with rheumatoid arthritis (RA), but have not been comparatively validated in Indian population. Objective To validate CDAI and SDAI in RA, taking DAS-28 as gold standard and to derive new cutoffs for CDAI and SDAI. Methods Patients fulfilling ACR/EULAR criteria for diagnosis of RA were studied. After complete history, physical examination and biochemical tests, patients were grouped into remission, low, moderate and high activity on the basis of pre-defined cut-offs for DAS-28, CDAI, and SDAI. Spearman’s correlation and group wise inter-rater agreement tests were performed. Using DAS-28 as gold standard, the sensitivity and specificity of CDAI and SDAI cut off were determined for predicting levels of disease activity by area under receiver operator characteristics curves. (AUROC) Results We studied 112 patients with RA, there was excellent correlation between DAS-28 and CDAI (r = 0.96 with 95% C.I. = 0.94−0.97), CDAI and SDAI (r=0.99, 95% C.I. 0.98−1), and DAS-28 and SDAI (r = 0.96, 95% C.I. = 0.94−0.97). There was a good inter-rater agreement between the various levels of disease activity as defined by DAS-28 and CDAI (weighed k = 0.598) and DAS-28 and SDAI (weighed k = 0.699) with excellent agreement between SDAI and CDAI categories (weighed k = 0.816). There was no statistically significant difference between AUROC of CDAI and SDAI and both performed equally well. Conclusion CDAI and SDAI are highly correlated with DAS-28 score hence are good markers of disease activity. The cut-off values for CDAI and SDAI used in western literature can be used with minor modifications in Indian scenario.

Introduction Various factors are known to determine the disease activity in patients with rheumatoid arthritis (RA). The main objective of this study was to establish the validity of the new tool of measurement of disease activity, Simplified Disease Activity Index (SDAI), in patients with RA in Indian population. Methods All patients with RA fulfilling the ACR classification criteria attending the rheumatology clinic at Nizam's Institute of Medical Sciences, Hyderabad over a period of 3 months were included in the study. A detailed assessment of each patient including their demographic characteristics, duration of the disease, number of tender and swollen joint counts, Westergren's ESR and C-reactive protein (mg/dL), patient's and physician's global assessment by VAS (0–10) were recorded. DAS28 and SDAI were calculated for each patient. Statistical analysis was done. Results Two hundred and sixteen patients were included in the study comprising 184 women and 32 men. Mean age of the patients was 42.94 ± 11.23 years and mean duration of disease was 4.10 ± 4.02 years. Mean DAS28 and SDAI were 5.19 ± 1.48 and 24.2 ± 16.06 respectively. ROC curve revealed that discriminative ability of SDAI was better than that of DAS28. The optimal cut-off points for treatment changes were 4.46 for DAS28 (sensitivity 88%, specificity 87.5%) and 12.6 for SDAI (sensitivity 92%, specificity 83%). Conclusion SDAI is a valid tool for measurement of disease activity in RA in Indian population and is as good as DAS28 in its ability to assess the patient's status.