238 Cutaneous dermatomyositis area and severity index activity score (CDASI-A) and associated patient-reported outcomes in a phase 2 clinical trial in dermatomyositis

Abstract

Retrospective reviews of clinical databases from two sites have identified strong associations between skin activity in dermatomyositis (DM), as measured by CDASI-A, and patient-reported quality-of-life (QoL). We hypothesized that associations between CDASI-A and QOL outcomes could also be demonstrated in the clinical trial setting. We evaluated correlations between CSADI-A and PROMIS Short Form domain scores, Skindex domain scores, Patient Global Assessment (PtGA) scores, and Physician Global Assessment (PGA) scores in a double-blind, randomized, placebo-controlled clinical trial. Data were from a 5-visit, 16-week Phase 2 trial of lenabasum, a cannabinoid receptor type 2 agonist, in 22 subjects with DM. CDASI-A scores and QOL outcomes collected at each study visit were correlated using linear mixed effect models to account for within-subject variability and repeated measures. As our goal was to correlate CDASI and QoL throughout the trial, analysis was performed without regard to treatment. Improvement in CDASI-A significantly correlated with PROMIS social role (p≤0.05). No other PROMIS domain scores correlated with the CDASI. The CDASI-A also significantly correlated with all Skindex scores (symptoms, functioning, emotions, and itch), all PtGA scores (global disease, itch, pain, and global skin), and all PGA scores (global disease, skin activity, and global skin), p<0.001 each. All reported correlations were in the appropriate direction. Our findings support that CDASI-A reflects both skin disease and QOL and is an appropriate outcome in DM clinical trials. Most PROMIS domains did not correlate with skin activity suggesting that Skindex and PtGA scores may better relate to skin activity as measured by the CDASI.