Abstract
The lack of a validated Chinese version of the Recap of Atopic Eczema questionnaire (RECAP) questionnaire limits its applicability. This prospective study, conducted at a Chinese tertiary hospital between April and November 2024, aimed to evaluate measurement properties of the Chinese RECAP. Participants completed RECAP and reference instruments at baseline, 1-3 days, and 4-6 weeks. Construct validity was evaluated through hypothesis testing, while reliability was assessed using standard error of measurement (SEMagreement) and intraclass correlation coefficient (ICCagreement). Interpretability of both single and change scores was examined using anchor-based methods. In total, 153 adults with atopic dermatitis (AD) (mean age 28.4 years, 51.0% male) were included, with approximately half having moderate-to-severe disease. Of the predefined hypotheses, 57.1% (single score) and 71.4% (change score) were confirmed. The SEMagreement was 1.99, and the ICCagreement was 0.96. Final RECAP bandings were established, with a binary cutoff of ≥ 11 defining uncontrolled AD. The Smallest Detectable Change was 5.5. while the Minimally Important Change was 3.5 using the receiver operating characteristics (ROC) method and 0.6 after adjustment via predictive modelling. Our finding confirmed that the Chinese RECAP is a valid, reliable, and responsive tool for evaluating eczema control. An improvement of ≥ 6 represents a real and clinically meaningful change.