Evaluating important change in cutaneous disease activity as an efficacy measure for clinical trials in dermatomyositis.

In patients with an initial CDASI-A score > 14 points, a 40% change in the CDASI-A score can be used to indicate a meaningful change in QoL in future dermatomyositis trials. What's already known about this topic? The Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI) is a validated disease assessment tool used to capture the extent of cutaneous activity and damage. The Skindex-29 and Dermatology Life Quality Index are standardized and validated measures of quality of life (QoL) for clinical trials and correlate with CDASI Activity (CDASI-A) scores. What does this study add? We identified what change in Skindex-29 scores over two consecutive visits would indicate an important change (a minimal clinically important difference) in QoL. We determined which change in CDASI-A scores over two consecutive visits would lead to a meaningful change in QoL. For patients with an initial CDASI-A score > 14 points, a 40% change in the CDASI-A score over two visits is associated with a meaningful change in QoL. What are the clinical implications of this work? Clinical trials can consider using a 40% change in the CDASI-A score as an end point when assessing the clinical efficacy of drugs.