Article Text
Abstract
Objectives There is an unmet need for accurate and user-friendly definitions of systemic lupus erythematosus (SLE) disease activity and remission. We aimed to derive and validate the SLE Disease Activity Score (SLE-DAS) definitions for disease activity categories and clinical remission state.
Methods Derivation was conducted at Padova Lupus Clinic (Italy). Validation was prospectively performed at Cochin Lupus Clinic (France) and by post hoc analysis of BLISS-76 trial. At each clinic, an expert classified patients in three categories: remission, mild or moderate/severe activity. The SLE-DAS cut-offs were derived using the receiver operating characteristic curve analysis in Padova cohort; its performance was assessed against expert classification in Cochin cohort and British Isles Lupus Assessment Group (BILAG) index in BLISS-76. Gold standard for clinical remission state was the fulfilment of Definition Of Remission In SLE. A Boolean and an index-based definitions of remission were sustained by chi-square automatic interaction detection algorithm. An SLE-DAS online calculator was developed and tested.
Results We included 1190 patients with SLE: 221 in the derivation cohort and 969 in the validation cohorts (150 from Cochin; 819 from BLISS-76). Derived cut-offs were: remission, SLE-DAS ≤2.08; mild activity, 2.08<SLE-DAS≤7.64; moderate/severe activity, SLE-DAS >7.64. Regarding validation in Cochin cohort, sensitivity and specificity are above 90%, 82% and 95% for remission, mild and moderate/severe activity, respectively. The SLE-DAS Boolean-based and index-based remission showed sensitivity of 100% and specificity above 97%.
Conclusion The SLE-DAS is an accurate and easy-to-use tool for defining SLE clinical remission state and disease activity categories, validated against expert assessment and BILAG.
- systemic lupus erythematosus
- disease activity
- outcomes research
- autoimmune diseases
Data availability statement
Data are available on reasonable request. All data relevant to the study are included in the article or uploaded as online supplemental information. Data are available on reasonable request from AD (ORCID 0000-0003-0548-4983). Reuse of data is not permitted by a third party without authorisation.
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Data availability statement
Data are available on reasonable request. All data relevant to the study are included in the article or uploaded as online supplemental information. Data are available on reasonable request from AD (ORCID 0000-0003-0548-4983). Reuse of data is not permitted by a third party without authorisation.
Footnotes
Handling editor Josef S Smolen
AD and LSI contributed equally.
Presented at These results were presented, in part, at the Annual European Congress of Rheumatology 2021 and published as a conference abstract (Jesus D, et al. Ann Rheum Dis 2021;80[Suppl1]:182-3).
Contributors DJ, AD and LSI contributed to the conception and design of the project, analysis and interpretation of data, drafting and critical revision of the manuscript; AM and CH contributed to the design of the project, statistical analysis, interpretation of data and critically revised the manuscript; PT, VA and NC developed the SLE-DAS online calculator and contributed to the analysis and interpretation of data and critically reviewed the manuscript; MZ, ML and LI contributed to patients follow-up in the Padova Lupus Clinic, analysis and interpretation of data and critically revised the manuscript; LI scored the SLE disease activity categories in Padova Lupus Cohort; ML, VLG and NC-C contributed to patients follow-up in the Cochin Lupus Clinic and contributed to the analysis and interpretation of data and critically revised the manuscript; NC-C also scored the SLE disease activity categories in the Cochin Lupus Clinic; all the authors approved the final version of the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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