3 INDEXES FOR ASSESSING DISEASE-ACTIVITY IN SLE - APPLICATION IN RETROSPECTIVE STUDIES ON ACTIVITY AND COURSE

Generally accepted criteria for evaluating disease activity in systemic lupus erythematosus (SLE) have not yet been established. At present three indices are widely used: SLAM, BILAG, and SLEDAI. Validity and reliability have been investigated mostly prospectively. Only a few investigations on their suitability for retrospective assessment of disease activity and of the course of the disease have been performed. We applied these three instruments in a retrospective study of disease activity in 52 SLE patients. They were found to have a high convergent validity (r = 0.91 to 0.74) and to correlate well with the clinician's decision concerning treatment intensity (r = 0.81 to 0.72). Their correlation with immunological parameters were only partially significant. Additionally, the course of the disease was evaluated retrospectively on 3 occasions over 6 months in 30 patients. Sensitivity in detecting changes was determined by the ratio of mean change and standard deviation of change (''Standardized Response Mean''/SRM). The SLAM was found to be significantly more sensitive in both the early phase (8 weeks) of observation (SRM = 0.88) and over the entire period (6 months: SRM = 0.93) than either BILAG (SRM = 0.47; 0.64) or SLEDAI (SRM = 0.46; 0.64). Based on its favourable combination of high validity and sensitivity, the SLAM appears to be especially well suited as a standard method in retrospective studies on SLE activity and course.