Sensitivity to change of 3 Systemic Lupus Erythematosus Disease Activity Indices: international validation

Abstract

Objective: Three indices, the SLE Disease Activity Index (SLEDAI), the Systemic Lupus Activity Measure (SLAM) and the British Isles Lupus Assessment Group (BILAG), have been found to be reliable and valid measures of disease activity in patients with systemic lupus erythematosus (SLE). Our aim was to investigate their use and comparative ability to assess change in disease activity over time.

Methods: Clinical and laboratory features of 8 patients with SLE on each of 3 consecutive visits were abstracted and sent in 3 separate packages to physicians from 8 centers. The order of the patient visit summaries was randomized, and the 3 indices rated in one of 6 specific sequences.

Results: The 3 indices were significantly (p < 0.01) correlated: SLEDAI/SLAM = 0.61, BILAG/SLAM = 0.55, SLEDAI/BILAG = 0.35. The sequence presented, the order of patients and order of index scoring did not contribute significantly (p > 0.05) to the variation of any of the 3 indices. All 3 indices detected differences among patients (p < 0.01). Differences between visits were detectable with SLEDAI (p = 0.04) but not with SLAM or BILAG:

Conclusion: Our study confirms that the SLEDAI, SLAM and BILAG are comparable disease activity measures. SLEDAI appears to be sensitive to change in disease activity over time.