Development and Validation Clinician and Patient Reported Photonumeric Scales to Assess Buttocks Cellulite Severity

BACKGROUND The Clinician Reported Photonumeric Cellulite Severity Scale (CR-PCSS) and Patient Reported PCSS (PR-PCSS) are newly developed tools for assessing cellulite severity. OBJECTIVE To report on the reliability, validity, and ability to detect a change in cellulite severity on the buttocks of adult women with the CR-PCSS and PR-PCSS. MATERIALS AND METHODS Content validity of both scales was established through concept elicitation and cognitive interviews. Test-retest reliability was evaluated, and intra-rater (both scales) and inter-rater (CR-PCSS only) reliability were estimated using intraclass correlation coefficients (ICCs) for agreement and consistency. Ability to detect a change was determined using the Subject-Global Aesthetic Improvement Scale (GAIS) or Investigator-GAIS as anchors. RESULTS For the CR-PCSS (n = 6) at baseline and Day 2, the mean interrater ICCs were $0.70 and mean intrarater ICCs (95% confidence interval [CI]) were $0.81 (0.72-0.90) for both buttocks. For the PR-PCSS (n = 99) at baseline and Day 14, the mean test-retest reliability ICCs (95% CI) were $0.86 (0.79-0.91) for both buttocks. A clinically meaningful change was 1.0 point on the PR-PCSS and 1.0 on the CR-PCSS. CONCLUSION The CR-PCSS and PR-PCSS reliably assess cellulite severity of the buttocks and can detect a clinically meaningful change after treatment for cellulite.