Applying the Cutaneous Lupus Erythematosus Disease Area and Severity Index to paediatric cutaneous lupus erythematosus

Abstract

The Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI) was created as a scoring tool to objectively assess disease severity in patients with cutaneous lupus erythematosus (CLE). Victoria Werth, the senior author of this study, led a multicentre collaborative effort to devise and validate the CLASI, which contains two scoring components for skin activity and damage. The CLASI, which was assessed for content validity by expert dermato-rheumatologists, has shown high inter-rater reliability (r = 0.86–0.92) and intrarater reliability (r = 0.96–0.99). Since its validation, various clinical trials have employed CLASI as a primary end point to assess therapeutic efficacy. Despite its widespread use, the CLASI had not been validated in paediatric patients with CLE. In fact, there has not yet been a validated disease severity scoring tool for this important patient population. The study detailed in this issue of the BJD addresses this important knowledge gap by measuring the reliability and validity of the CLASI in a group of paediatric patients with CLE. To confirm its ease of use, the authors investigated the ability of 12 paediatric dermatologists and rheumatologists to use the CLASI. The CLASI activity interand intrarater reliability scores were excellent for both paediatric dermatologists and rheumatologists (intraclass correlation coefficient > 0.9). The CLASI damage interand intrarater reliability scores ranged from poor to excellent. CLASI activity and damage scores showed excellent construct validity when compared with Physician’s Global Assessment (PGA) scores. Exit questionnaires showed physician preference for the CLASI over the PGA in terms of assessing disease severity of CLE and ease of use. The study has important implications for paediatric CLE. Firstly, the study confirms the strong psychometric properties of the CLASI in paediatric CLE. Thus, clinical studies may use the CLASI to objectively evaluate treatment efficacies. Secondly, the excellent interand intrarater reliability for CLASI activity scores in paediatric dermatologists and rheumatologists broadens the ability of clinical trials studying paediatric patients with CLE to recruit both groups of physicians to participate as investigators. These results mirror closely what had been previously shown with adult dermatologists and rheumatologists. Thirdly, the availability of the CLASI as an objective outcome measure will likely spur the interest of pharmaceutical companies to conduct trials in paediatric CLE, as it has done for adult CLE. Further work still needs to be done with the CLASI in paediatric CLE. This includes determining a minimal clinically important difference for the CLASI in paediatric patients with CLE that would reflect a meaningful improvement for patients. With her adult CLE patient cohort at the University of Pennsylvania, Victoria Werth and her group determined the minimal clinically important difference of the CLASI activity score to be an increase of at least four or 20%. This set the stage for clinical trials to start with this benchmark to assess therapeutic efficacy. The lack of an objective clinical measure for disease activity has been an obstacle impeding implementation of paediatric CLE clinical trials. The study’s validation of the CLASI as an outcome measure for paediatric patient with CLE is an important first step to addressing this glaring problem.