Treating-to-target: remission and low disease activity in systemic lupus erythematosus versus rheumatoid arthritis

To compare the proportion of patients in remission and low disease activity (LDA) between rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE).

Outpatient record data of 100 patients with SLE and of 100 matched patients with seropositive RA, with at least three consecutive outpatient visits each between August 2021 and January 2023 were compared. Documentation at every visit included SLE Disease Activity Index 2000 (SLEDAI-2K) for SLE, Simplified Disease Activity Index (SDAI) for RA and visual analogue scales (VAS). Remission and LDA were defined by SDAI cut-offs in RA and Definition of Remission in SLE (DORIS) remission and Lupus Low Disease Activity State (LLDAS) in SLE.

Remission or LDA were present in 347 (88.5%) of 392 visits of SLE and 354 (91.0%) of 389 visits of RA patients (P = 0.2885). Remission was more common in SLE (79.3%) than RA (69.4%) data points (P = 0.0018). Physician global assessment (PhGA) was not significantly different between SLE and RA patients in low disease activity, and only slightly higher in SLE in remission (P = 0.0002). C-reactive protein (CRP) was increased (P = 0.0107) but the erythrocyte sedimentation rate was similar in active RA vs active SLE.

Treat-to-target (T2T) goals were similarly met for SLE and RA patients on current treatment. Despite differences between the diseases and according to differences in definitions, these data suggest that the SLE definitions for remission and LDA were successfully modelled on those of RA. The rates with which favourable states were noted support the T2T approach in SLE.