PO:15:224 | Measuring disease activity in Systemic Lupus Erythematosus patients: SLE-DAS usefulness in real-life setting

Valeria Moretti, Fulvia Ceccarelli, Claudia Ciancarella, Cristina Garufi, Alessandra Ida Celia, Silvia Mancuso, Angelica Gattamelata, Simona Truglia, Francesca Romana Spinelli, Cristiano Alessandri, Fabrizio Conti | La sapienza Università di Roma, Italy

Objective. The assessment of disease activity in Systemic Lupus Erythematosus (SLE) remains a challenge due to disease’s clinical and serologic heterogeneity. Thereby, defining a state of remission can also be extremely complex. According to the last recommendations for SLE management, remission was defined for the presence of c-SLEDAI=0, glucocorticoids <= 5 mg/daily, HCQ treatment, immunosuppressive/biological treatments at stable tolerated dose. Recently, it has been proposed the SLE-DAS, a new activity index able to provide an accurate and feasible measure for disease activity, with improved sensitivity to change compared to SLEDAI-2k. Here, we applied SLE-DAS in a large SLE cohort to evaluate its correlation with SLEDAI-2k and the concordance between the SLE-DAS based remission and that proposed by EULAR recommendations. Secondly, we evaluated the possible association between SLE-DAS and chronic damage.

Methods. We evaluated consecutive patients. Disease activity was assessed by SLE-DAS, SLEDAI-2k and c-SLEDAI; then we evaluated the achievement of remission according to SLE-DAS definition (SLE-DAS <= 2.08 + PDN <= 5mg/daily) and to EULAR recommendations. Finally, we assessed chronic damage by applying the SLICC Damage Index (SDI). All the patients were prospectively evaluated after 12 months.

Results. We enrolled 150 patients [M/F 16/134, median age 50 years (IQR 16), median disease duration 191 months (IQR 213)]. At first evaluation, median val¬ues of SLE-DAS, SLEDAI-2k and c-SLEDAI were 1.12 (IQR 2,37), 2 (IQR 3,2), and 0 (IQR 1), respectively. A significant cor¬relation between SLE-DAS values and both SLEDAI-2k (r=0.9, p<0.0001, 95%CI 0.93-0.96,) and c-SLEDAI (r=0.78, p<0.0001, 95%CI 0.71-0.81) (figure 1A and 1B, respectively) was found. Then we assessed the prevalence of remission: 106 patients (70.6%) meet the SLE-DAS based definition, while 100 (66.6%) the one proposed by EULAR recommendations. Both definitions demonstrated an agreement of 94%, with a Cohen’s kappa equal to 0.6. Furthermore, by applying a ROC analysis we identified for SLE-DAS a cut-off value equal to 0.7 able to discriminate patients with EULAR-based remission (AUC 0.91; SE 0.028, 95%CI 0.86-0.97; figure 1C). Moving on damage assessment, 90 patients (60%) showed a SDI value >= 1 (mean±SD 1.2±1.46); after 12 month of follow-up we found a progression for chronic damage in 11 patients (7.3%), with a significant increase in SDI values (p=0.001; figure 1D). Finally, we compared patients with and without progression in SDI values: progressorsshowed higher median SLE-DAS values at baseline compared with non progressors [2.1 (IQR 4.8) versus 1.3 (IQR 2.1), p=ns).

Conclusions. Our analysis suggests the usefulness of SLE-DAS in a real-life context. This feasible index appears able to identify patients in remission according to EULAR-based remission and could provide information about the trajectory of chronic damage. Then, the use of SLE-DAS could facilitate disease activity assessment even in a routine setting.