Assessment of Intra- and Inter-Rater Reliability of Three Methods for Measuring Atopic Dermatitis Severity: EASI, Objective SCORAD, and IGA

Abstract

Background: Numerous different scoring systems have been proposed for assessing the severity of atopic dermatitis (AD). Many of these methods did not undergo proper validation and reliability testing. Objective: The aim of our study was to compare the reliability and reproducibility of the Eczema Area and Severity Index (EASI), objective Scoring Atopic Dermatitis (oSCORAD), and Investigator Global Assessment (IGA). Methods: On the scoring day, 10 trained dermatologists evaluated 10 adult patients with AD using the EASI, oSCORAD, and IGA. All subjects were assessed twice by each physician. Correlations between measures were analysed using the Pearson correlation coefficient. The intra-class correlation coefficient (ICC) was calculated to assess intra-rater reliability; the coefficient of variation (CV) was used to assess inter-rater variability. Results: Significant positive correlations were observed between each scale in both assessments. The ICCs for the EASI and oSCORAD were 0.71 and 0.66, respectively, indicating good reliability, while the ICC for the IGA (0.54) indicated only fair reliability. The CVs for the oSCORAD and IGA were 28.1 and 33.0, respectively, indicating moderate variability. The CV for the EASI was 66.5, indicating high variability. Conclusion: Among the 3 compared scales, the oSCORAD had the highest inter-rater reliability, whereas the EASI had the highest intra-rater reliability. None of the 3 scoring methods showed a significant advantage over the other. Thus, a reliable assessment of AD severity requires the use of at least 2 independent measurements simultaneously.