Objectives. To examine SLEDAI-2000 cut-off scores for definition of active SLE and to determine the sensitivity to change of SLEDAI-2000 for the assessment of SLE disease activity and minimal clinically meaningful changes in score.Methods. Data from two multi-centre studies were used in the analysis: in a cross-sectional and a longitudinal fashion. At every assessment, data were collected on SLEDAI-2000 and treatment. The cross-sectional analysis with receiver operating characteristic (ROC) curves was used to examine the appropriate SLEDAI-2000 score to define active disease and increase in therapy was the reference standard. In the longitudinal analysis, sensitivity to change of SLEDAI-2000 was assessed with multinomial logistic regression. ROC curves analysis was used to examine possible cut-points in score changes associated with change in therapy, and mean changes were estimated.Results. In the cross-sectional analysis, the most appropriate cut-off scores for active disease were 3 or 4. In the longitudinal analysis, the best model for predicting treatment increase was with the change in SLEDAI-2000 score and the score from the previous visit as continuous variables. The use of cut-points was less predictive of treatment change than the use of continuous score. The mean difference in the change in SLEDAI-2000 scores, adjusted for prior score, between patients with treatment increase and those without was 2.64 (95% CI 2.16, 3.14).Conclusions. An appropriate SLEDAI-2000 score to define active disease is 3 or 4. SLEDAI-2000 index is sensitive to change. The use of SLEDAI-2000 as a continuous outcome is recommended for comparative purposes.

Objective. To develop an additive numerical scoring scheme for the BILAG-2004 index.Methods. SLE patients were recruited into this multi-centre cross-sectional study. At every assessment, data were collected on disease activity and therapy. Logistic regression was used to model an increase in therapy, as an indicator of active disease, by the BILAG-2004 index score in the nine systems. As both indicate inactivity, scores of D and E were set to 0 and used as the baseline in the fitted model. The models were used to determine the numerical values for Grades A–C. Different scoring schemes were compared.Results. There were 1510 assessments from 369 SLE patients. The coding schemes suggested for the Classic BILAG index (A = 12, B = 5, C = 1, D/E = 0 and A = 9, B = 3, C = 1, D/E = 0) did not fit the data well. A coding scheme (A = 12, B = 8, C = 1 and D/E = 0) was recommended, based on analysis results and consistency with the numerical coding scheme of the Classic BILAG index.Conclusion. A reasonable additive numerical scoring scheme based on treatment decision for the BILAG-2004 index is A = 12, B = 8, C = 1, D = 0 and E = 0.