Sensitivity of the systemic lupus erythematosus disease activity index, British Isles lupus assessment group index, and systemic lupus activity measure in the evaluation of clinical change in childhood-onset systemic lupus erythematosus

OBJECTIVE: To investigate whether 3 disease activity indices commonly used to evaluate systemic lupus erythematosus (SLE) in adults are sensitive to clinical change in children, and thus suitable for the use in the management of childhood-onset SLE. METHODS: Thirty-five SLE patients who were newly diagnosed between 1993 and 1997, had an age at onset of 6-16 years (26 female and 9 male), and were currently being followed up at The Hospital for Sick Children (followup of 9 months to 4 years) were reviewed. The SLEDAI (Systemic Lupus Erythematosus Disease Activity Index), BILAG (British Isles Lupus Assessment Group index), and SLAM (Systemic Lupus Activity Measure) were applied at up to 4 occasions during the disease course: at the time of diagnosis, 6 months postdiagnosis, at the time of a flare (a deterioration in clinical presentation or laboratory results requiring initiation or increase of either corticosteroids or "second-line" drugs), and 6 months postflare. The sensitivity of the 3 measures to change, as gauged by the effect size (ES), effect size index (ESI), standard response mean (SRM), responsiveness statistic (RS), and relative efficiency index (REI), were compared. RESULTS: All 3 tools were very sensitive to change in disease activity (ES >0.8, ESI >2.3, SRM >0.6, RS >0.86, REI >0.72), but were ranked differently depending on the statistic used for comparison. CONCLUSION: All 3 measures of disease activity are highly sensitive to clinical change in children; none showed an overall superiority. The SLEDAI, BILAG, and SLAM can all be used to study response to treatment in children with SLE.