The construct validity, responsiveness, reliability and interpretability of the Recap of atopic eczema questionnaire (RECAP) in children.

ABSTRACT

BACKGROUND: The Recap of atopic eczema questionnaire (RECAP) was developed to measure eczema control in patients with atopic dermatitis (AD). The measurement properties of RECAP have not yet been validated in caregivers of children with AD. OBJECTIVES: To assess the construct validity, responsiveness, reliability and interpretability of the Dutch proxy version of RECAP. METHODS: A prospective validation study was conducted in children (aged < 12 years) with AD and their caregivers (in a Dutch tertiary hospital). At three timepoints (T0 = baseline; T1 = after 1-7 days; T2 = after 4-8 weeks) RECAP and multiple reference instruments were completed by caregivers of child patients. Single- and change-score validity (responsiveness) were tested with a priori hypotheses on correlations with reference instruments. Intraclass correlation coefficients (ICCagreement) and standard error of agreement (SEMagreement) were reported. Bands for perceived eczema control were proposed. The smallest detectable change (SDC) and minimally important change (MIC) were determined. Two anchor-based methods based on receiver operating characteristic curve (ROC) and predictive modelling were used to determine the MIC. RESULTS: A total of 231 children with AD and their caregivers participated. Of our a priori hypotheses for single-score and change-score validity, 77% and 80% were confirmed, respectively. A stronger correlation than hypothesized was found for all rejected hypotheses.Excellent reliability was found (ICCagreement = 0.94, 95% confidence interval 0.90-0.96). The SEMagreement was 1.9 points. The final banding was 0-1 (completely controlled), 2-7 (mostly controlled), 8-12 (moderately controlled), 13-18 (a little controlled) and 19-28 (not at all controlled). A cutoff point of ≥ 8 was selected to identify children whose AD is not under control. The SDC was 5.3 and the MIC values were 1.5 and 3.6 for the ROC and predictive modelling approaches, respectively. No floor or ceiling effects were observed. CONCLUSIONS: The proxy version of RECAP is a valid, reliable and responsive measurement instrument for measuring eczema control in children with AD. An improvement of ≥ 6 points can be regarded as a real and important change in children with AD.

Atopic dermatitis (AD) is a skin disease that affects children and adults. People with AD (eczema) and other stakeholders have identified perceived 'eczema control' as an important outcome to investigate in research. For this purpose, the Recap of atopic eczema (RECAP) questionnaire was developed, consisting of seven items to measure eczema control in people with AD. However, when developing questionnaires, they must be examined to ensure they are relevant, reliable and sensitive enough to detect meaningful change before and after any new treatment. Prior studies have demonstrated that the RECAP is suitable for adults with AD, but studies investigating whether the RECAP is suitable for children are lacking. A study of 231 children (under 12 years old) with AD and their caregivers was conducted in the Netherlands. Caregivers completed the RECAP questionnaire at three time points at the start of the study, after 1­7 days and after 4­8 weeks. The researchers assessed AD severity and eczema control using other measures for comparison. RECAP scores from children whose caregivers reported unchanged eczema control were used to assess how reproducible this questionnaire was. RECAP scores of caregivers who reported change in eczema control were used to examine sensitivity to change. Statistical tests were used to analyse findings. The researchers found that RECAP accurately measures changes in eczema control over time and was sensitive enough to detect small changes in eczema control. Overall, the authors concluded that the RECAP questionnaire is valid, reproducible and responsive. Furthermore, they consider an improvement of at least 6 points to represent a genuine improvement in Dutch children.