A pilot comparison study of four clinician-rated atopic dermatitis severity scales.

BACKGROUND: There are multiple severity outcome measures for atopic dermatitis (AD). There is a need to compare the reliability of these measures. OBJECTIVES: To compare the inter-rater and intrarater reliability of the objective Scoring Atopic Dermatitis (oSCORAD), Eczema Area and Severity Index (EASI), Six Area, Six Sign Atopic Dermatitis (SASSAD) and Three Item Severity index (TIS); and to analyse the correlation between these outcome measures and the quality-of-life instruments Patient-Orientated Eczema Measurement, Dermatology Life Quality Index and Skindex-29. METHODS: Twelve patients with AD attended a 1-day scoring exercise by five trained dermatology clinicians. Inter-rater and intrarater reliability were assessed using the intraclass correlation coefficient (ICC). Correlation between clinician-rated and patient-reported measures was analysed using Spearman's rho. RESULTS: Regarding inter-rater reliability, EASI and SASSAD showed good reliabilities, with ICCs of 0·730 [95% confidence interval (CI) 0·500-0·900] and 0·680 (95% CI 0·440-0·880), respectively. However, the ICCs were poor for TIS and oSCORAD, with 0·497 (95% CI 0·233-0·785) and 0·498 (95% CI 0·234-0·785), respectively. Separate body surface area (BSA) component analyses showed that the oSCORAD BSA component contributed to its inter-rater variations. Regarding intrarater reliability, EASI and TIS showed excellent ICCs of 0·886 (95% CI 0·744-0·952) and 0·820 (0·614-0·923), respectively, while SASSAD showed a good reliability with an ICC of 0·720 (95% CI 0·424-0·878). However, the intrarater ICC was poor for oSCORAD, with 0·446 (95% CI 0·037-0·730). Regarding correlation with patient-reported measures, only SASSAD demonstrated moderate correlation with Skindex-29 (ρ = 0·611, P = 0·035). CONCLUSIONS: EASI demonstrated the highest inter-rater and intrarater reliability, supporting it as the optimal AD severity outcome measure.