Download files
Abstract
Background: Despite the existence of multiple outcome measures for the clinical signs of atopic dermatitis (AD), there is a need to standardise and validate them, especially for skin of colour patients.
Primary objectives: To compare the reliability of commonly used AD outcome measures and to validate them in skin of colour patients.
Methods: First study: 12 AD patients were scored by 5 clinicians using Eczema Area Severity Index (EASI), objective SCORing AD score (oSCORAD), Six Area Six Signs AD (SASSAD) and Three Items Severity (TIS). Second study: photos of 18 AD patients of various skin colours were scored by 5 clinicians using EASI, oSCORAD, SASSAD and TIS. Third study: 25 AD patients of various skin colours were scored by 5 clinicians over 2 scoring sessions using EASI, oSCORAD, IGA and greyscale. Melanin index was measured using a mexameter. Reliability was assessed using the intra-class correlation coefficient (ICC).
Results:
First study - Inter-rater reliability: the EASI and SASSAD showed good ICCs of 0.730(95%CI: 0.500-0.900) and 0.680(0.440-0.880), but TIS and oSCORAD had poor ICCs; Intra-rater reliability: EASI and TIS showed excellent ICCs of 0.886(0.744-0.952) and 0.820(0.614-0.923), while SASSAD showed a good ICC and oSCORAD had a poor ICC.
Second study had poor validity and was improved upon by the third study, where the inter-rater ICCs were: EASI 0.827(0.658-0.941) in lighter patients and 0.774(0.598-0.906) in skin of colour; oSCORAD 0.680(0.441-0.880) in lighter patients and 0.736(0.544-0.889) in skin of colour; IGA 0.803(0.618-0.932) in lighter patients and 0.696 (0.490-0.868) in skin of colour; grey-scale had an ICC of 0.638(0.400-0.838) alone and 0.776(0.601-0.907) when replacing EASI’s erythema scale. All scores had excellent intra-rater reliability. Erythema did not contribute to variability using coefficient of variance analysis.
Conclusions: EASI demonstrated the excellent reliability in patients of all skin colours, supporting it as the optimal AD outcome measure.