Objective: To validate the Eczema Area and Severity Index (EASI) by assessing its internal consistency, reliability and sensitivity to change and by correlating it to other efficacy parameters.
Design: Three short-term and two long-term double-blind, randomized, controlled trials, performed in 138 study centres in Europe, South Africa, Australia, New Zealand, and North and South America.
Patients and methods: In total, 1550 paediatric patients with atopic dermatitis were studied. Pimecrolimus cream 1% was used twice daily to treat atopic dermatitis. The three short-term studies were placebo controlled. The two long-term studies evaluated the efficacy and safety of early intervention with pimecrolimus to prevent progression to disease flare requiring topical corticosteroid treatment, compared with reactive treatment with topical corticosteroids to treat flares of atopic dermatitis.
Main outcome measures: Five parameters were measured: (i) the EASI (range of score 0-72); (ii) Investigators' Global Assessment (IGA), using a six-point (0-5) scale; (iii) patients' assessment, using a four-point (0-3) scale; (iv) severity of pruritus assessment, using a four-point (0-3) scale; and (v) a quality-of-life evaluation.
Results: The EASI score varied in parallel and in correlation with the IGA, pruritus and patients' assessment. All correlation coefficients were statistically different from 0 (P < 0.05). The EASI correlated well with each of its components, and all paired comparisons were within agreed limits. The EASI showed good sensitivity to changes in severity.
Conclusion: In a large, multinational patient population with atopic dermatitis, the EASI showed good validity, reliability and sensitivity to change and correlated well with other measures of severity. It therefore qualifies as a valid method of assessment in clinical studies of atopic dermatitis.