Validation of the Self-Reported Psoriasis Treatment Convenience Scale (PTCS).

INTRODUCTION Adherence to topical treatments for psoriasis is reported to be poor. One key contributing factor is the inconvenience associated with formulations that may be greasy, time consuming to apply, and slow to absorb. There is a paucity of patient-reported outcome measures that evaluate psoriasis patients' perceptions of treatment convenience. The Psoriasis Treatment Convenience Scale (PTCS) was therefore developed and validated. METHODS Following a literature review of issues relating to convenience of topical treatments, important items were identified and a draft version of the PTCS was developed and underwent content validity testing (n = 20). The revised scale was included in a clinical trial of topical therapy (n = 794; NCT03308799), and psychometric testing was performed. RESULTS The final questionnaire included five core items and one overall satisfaction question. In psychometric testing, the scale demonstrated stability across trial population, and good validity, reliability, and sensitivity. CONCLUSION The PTCS is a new, reliable, sensitive, validated tool for the assessment of patient-reported treatment convenience. Use of the PTCS will facilitate evaluation of convenience as part of the clinical development of topical therapies, and thus may help to improve patient adherence and, therefore, treatment outcomes.