Validation of the RECAP measure of eczema long-term control
Research comparing the effectiveness of different eczema treatments is limited by inconsistency in both outcomes assessed and the measures used. HOME (Harmonising Outcome Measures for Eczema) is an international collaboration established to agree a core set of outcomes to be reported in all trials of eczema treatments. RECAP is a patient-reported outcome measure of eczema control, one of four key domains recommended by HOME. This is the first study to independently assess the validity and reliability of RECAP.
Two online questionnaires (baseline and follow-up) were administered two weeks apart. The online questionnaires included RECAP and validated scales of eczema severity (POEM) and quality of life (PROMIS). People with eczema, or carers of children with eczema, were recruited through social media and by engagement with patient charities/organisations.
Data from 380 baseline (57.4% adults) and 188 follow-up (58.5% adults) questionnaires were analysed. RECAP had a high (99.7%) completion rate with a good distribution of scores and internal consistency (Cronbach’s alpha adults=0.89, children=0.92). Almost half of participants thought RECAP appeared to measure long-term control. Hypothesised associations between RECAP and eczema severity, global self-rated eczema control, quality of life, self-reported change in severity of eczema, and change scores for RECAP and POEM were observed as expected. RECAP had a high intraclass correlation coefficient (adult=0.85, child=0.89). RECAP appears to have good acceptability, validity, test-retest reliability and responsiveness to change. Further work is required to investigate its validity in community and clinic populations.
HOME VII consensus meeting took place in Japan in April 2019 and data from this study informed the decision to recommend RECAP as one of two measures of long-term control to be collected in all future trials of eczema treatments. RECAP may also be used in a clinical setting to assess patients’ control of their eczema.