Interpretation of CompAQ and Skindex-16 scores among patients with acne

Summary: Abstract Body: This international cohort study among those with acne sought to establish interpretability criteria for CompAQ (patient reported outcome [PRO] with five domains scored 0-32) and Skindex-16 (PRO with three domains scored 0-100). Specifically, we employed receiver-operating characteristic (ROC) analysis to identify cutoffs corresponding to mild/moderate/severe effects of acne on quality of life (i.e., severity strata), with a patient global assessment of acne serving as the anchor. We also used anchor and distribution-based approaches to assess what change in scores correspond with a meaningful difference in quality of life (i.e., minimally important difference [MID]). Given complex scoring systems can hinder PRO utilization, we sought more intuitive values when possible. Among 315 participants, severity strata derived from ROC analyses achieved fair to moderate concordance. We recommend cutoffs of 5/15/20 to define mild/moderate/severe strata for CompAQ emotions and symptoms; 5/10/15 for CompAQ social judgement and interaction; 15/20/25 for CompAQ treatment; 20/40/60 for Skindex-16 emotions; and, 15/30/45 for Skindex-16 functioning and symptoms. Anchor and distribution-based MID calculations closely approximated one another. We recommend a 4-point change to define MID for CompAQ and 15-point change for Skindex-16. By defining the clinical meaning of CompAQ and Skindex-16 scores, our findings will facilitate use of these PROs in clinical practice and trials. Michael R. Nock^{1, 2}, Delaney Griffiths¹, Ali Shields¹, Karen Michael³, Nuha Nasir⁴, Jaefer Mohamad³, James Choe¹, Alison M. Layton^{5, 6}, Jerry Tan^{7, 8}, Hazel H. Oon^{9, 10}, John S. Barbieri¹ 1. Dermatology, Brigham and Women's Hospital, Boston, MA, United States. 2. Dermatology, Yale University School of Medicine, New Haven, CT, United States. 3. Western University Schulich School of Medicine and Dentistry - Windsor Campus, Windsor, ON, Canada. 4. Department of Health Sciences, Brock University, St. Catharines, ON, Canada. 5. Skin Research Centre, University of York, York, England, United Kingdom. 6. Dermatology, Harrogate and District NHS Foundation Trust, Harrogate, England, United Kingdom. 7. Western University, Windsor, ON, Canada. 8. Windsor Clinical Research Inc., Windsor, ON, Canada. 9. National Skin Centre, Singapore, Singapore. 10. Skin Research Institute of Singapore, Singapore, Singapore. Clinical Research: Epidemiology and Observational Research