Reliability and convergent validity of the cutaneous sarcoidosis activity and morphology instrument for assessing cutaneous sarcoidosis.

IMPORTANCE: A validated scoring system is essential to assess the effect of therapeutic interventions on a disease. The instrument introduced here captures sarcoidosis disease activity in a reliable, reproducible manner, which will help standardize clinical trial outcomes and allow comparative efficacy studies in the future and may help lead to more robust data regarding the effect of different treatments on cutaneous sarcoidosis. OBJECTIVE: To assess the reliability and convergent validity of the Cutaneous Sarcoidosis Activity and Morphology Instrument (CSAMI) and Sarcoidosis Activity and Severity Index (SASI) for evaluating cutaneous sarcoidosis outcomes. DESIGN AND SETTING: Cross-sectional study evaluating cutaneous sarcoidosis disease severity using CSAMI, SASI, and Physician's Global Assessment (PGA) as reference in the dedicated cutaneous sarcoidosis clinic of a teaching hospital. PARTICIPANTS: Eight dermatologists evaluating cutaneous sarcoidosis in 11 patients. INTERVENTION: Evaluation using the study instruments. MAIN OUTCOMES AND MEASURES: Primary outcomes included interrater and intrarater reliability and convergent validity; secondary outcomes, correlation with quality-of-life measures and time required for completion. RESULTS: All instruments demonstrated good to excellent intrarater reliability. Interrater reliability was excellent for CSAMI Activity scores (intraclass correlation coefficient, 0.82 [95% CI, 0.66-0.94]) and fair to poor for CSAMI Damage scores (0.42 [0.21-0.72]), modified Facial SASI (0.40 [0.17-0.72]), and PGA scores (0.40 [0.18-0.70]). CSAMI Activity and Damage scores and modified Facial SASI all demonstrated convergent validity with statistically significant correlations with PGA scores. Trends for correlations were seen between CSAMI scores and specific Skindex-29 quality-of-life domains. Although CSAMI required longer time to complete than SASI, both were scored within adequate time for use in clinical trials. CONCLUSIONS AND RELEVANCE: CSAMI appears to be a reliable and valid outcome instrument to measure cutaneous sarcoidosis and may capture a wide range of body surface and cutaneous morphologic types. This instrument can be adopted into clinical practice and clinical trials to allow physicians to assess the intensity of their patients' cutaneous sarcoidosis disease activity. Widespread use of one metric for disease severity assessment can help standardize the evaluation of the effect of various treatments on the disease. Future research is necessary to demonstrate its sensitivity to change and to confirm its correlation with quality-of-life measures.