Small changes in outpatients lupus activity are better detected by clinical instruments than by laboratory tests

To evaluate and compare responsiveness of laboratory and clinical measures over 4 months in outpatient systemic lupus erythematosus (SLE).

We studied 23 patients with SLE at monthly intervals during 4 mo and collected demographic data, prednisone dose, global patient and physician assessment of disease activity on 10 cm visual analog scales (VAS), scores on 3 clinical measures of lupus disease activity [SLE disease activity index (SLEDAI), SLE activity measure (SLAM), lupus activity index (LAI)], and results of 5 routine laboratory tests [erythrocyte sedimentation rate (ESR), anti-dsDNA, C3, C4, circulating immune complexes]. We calculated correlations between a particular measure and our gold standard (physician's VAS) for individual patients and pooled this information using a novel application of the meta-analytic approach.

The range of disease activity by patient and physician VAS varied from inactive to moderately active> Change in patient global assessment and all 3 clinical measures showed significant positive correlations with change in physician VAS (p < 0.05). Change in ESR, anti-dsDNA, or level of C3, C4, or circulating immune complexes did not correlate with change in physician VAS.

Clinical measures of disease activity in SLE are more responsive to small changes than traditional laboratory tests. All 3 clinical measures appeared to perform equally well. At least one SLE disease activity measure should be used in SLE trials. The new analytic method will likely be of value in similar evaluations of responsiveness in other diseases.