Objective The severity and disease course of cutaneous lupus erythematosus (CLE) are highly variable. Consequently, outcome measures for CLE clinical improvement are heterogeneous, complicating treatment decisions and therapeutic development. This study characterises CLE outcome measures and identifies the influence of clinical improvement thresholds on strengths of associations with patient demographic and clinical factors.
Methods In this pilot cohort study, multivariable models identified factors associated with CLE activity and skin damage improvement, defined as relative decreases in Cutaneous Lupus Activity and Severity Index (CLASI) activity (CLASI-A) and damage (CLASI-D) scores, over ranges of response thresholds.
Results 66 patients with 119 visit-pairs were included in the CLASI-A analysis. 74 patients with 177 visit-pairs were included in the CLASI-D analysis. Factors associated with CLE activity and damage improvement depended on the response threshold. Some associations were stronger at more stringent thresholds, including subacute CLE predominance with increased likelihood of CLASI-A improvement (R 2=0.73; 50% reduction: OR 1.724 (95% CI 0.537 to 5.536); 75%: 5.67 (95% CI 1.56 to 20.5)) and African-American race with decreased likelihood of CLASI-D improvement (R 2=0.80; 20%: 0.40 (95% CI 0.17 to 0.93); 40%: 0.25 (95% CI 0.08 to 0.82)). Other associations were stable across multiple thresholds, including older age of CLE development with increased likelihood of CLASI-A improvement (R 2=0.25; 50%: 1.05 (95% CI 1.01 to 1.09]; 75%: 1.05 (95% CI 1.00 to 1.10)) and higher initial disease activity with decreased likelihood of CLASI-D improvement (R 2=0.55; 20%: 0.91 (95% CI 0.84 to 0.98); 40%: 0.88 (95% CI 0.79 to 0.97)).
Conclusions Examining a range of CLASI threshold outcomes can comprehensively characterise changes in disease course in patients with CLE. Insufficiently stringent thresholds may fail to distinguish meaningful clinical change from natural fluctuation in disease activity.
- outcomes research
- disease activity
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Contributors BAN and BFC designed the study and drafted the manuscript. All authors were responsible for acquisition, analysis and interpretation of the data. BAN performed the statistical analysis. BFC obtained funding and supervised the study.
Funding This study was supported in part by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award Number K23AR061441.
Disclaimer The content is solely the responsibility of the authors and does not necessarily represent the official views of the University of Texas Southwestern Medical Center at Dallas and its affiliated academic and health care centers or the National Institutes of Health.
Competing interests BFC is an investigator for Daavlin Corporated, Biogen Incoporated and Pfizer Incorporated. He is a consultant for Viela Bio.
Patient consent for publication Not required.
Ethics approval This study was approved by the UTSW Institutional Review Board.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information.
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