Organ manifestations influence differently the responsiveness of 2 lupus disease activity measures, according to patients' or physicians' evaluations of recent lupus activity.

OBJECTIVE

To determine (1) which organ system manifestations contribute to the overall responsiveness of the Systemic Lupus Activity Measure (SLAM, revised 1991 with minor modifications as SLAM-R) and the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI); and (2) whether responsive items differ for physicians and patients.

METHODS

Blinded data were obtained from repeated visits of 76 patients in the Study of Methotrexate in Lupus Erythematosus. At each visit, physicians and patients reported improvement, no change, or deterioration, and physicians then completed SLAM-R and SLEDAI. Items in SLAM-R and SLEDAI were grouped by organ system. The generalized estimating equations approach was used to measure associations between change in organ system activity and physician or patient perception of change in overall disease activity. The outcomes assessed, in separate analyses, were improvement and deterioration from the previous visit.

RESULTS

Seventy-six patients contributed a total of 471 observations. The strongest correlates of physician-reported improvement were decreased constitutional, gastrointestinal (GI), and musculoskeletal involvement (components of SLAM-R), and decreased musculoskeletal (MSK) and central nervous system involvement (SLEDAI). Improvement reported by patients was most strongly associated with decreases in erythrocyte sedimentation rate and MSK and reticuloendothelial activity (SLAM-R), and in MSK activity (SLEDAI). Increased integument and MSK subscores (SLAM-R) and serosal and MSK subscores (SLEDAI) were associated with overall deterioration reported by physicians. Patient-reported deterioration was associated with increased GI subscores (SLAM-R) and with no changes in organ system involvement in SLEDAI.

CONCLUSION

Organ systems associated with reported change in overall SLE activity differed between SLAM-R and SLEDAI, between patients and physicians, and between each direction of change.