Validation of ‘ItchApp©’ in Poland and in the USA: multicentre validation study of an electronical diary for the assessment of pruritus

• Published in: Journal of the European Academy of Dermatology and Venereology Vol. 33; no. 2; pp. 398 - 404
• Main Authors: Schnitzler, C., Rosen, J., Szepietowski, J.C., Reich, A., Yosipovitch, G., Reszke, R., Nattkemper, L.A., Osada, N., Pihan, D., Ständer, S., Zeidler, C.
• Format: Journal Article
• Language: English
• Published: England 01.02.2019
• Subjects: Adult; Age Factors; Aged; Diagnosis, Computer-Assisted - methods; Female; Humans; Male; Medical Records; Middle Aged; Mobile Applications - standards; Mobile Applications - statistics & numerical data; Poland; Pruritus - diagnosis; Risk Assessment; Sampling Studies; Sensitivity and Specificity; Severity of Illness Index; Sex Factors; Surveys and Questionnaires; United States; Young Adult; Poland; United States
• ISSN: 0926-9959; 1468-3083; 1468-3083
• DOI: 10.1111/jdv.15300

Background Although chronic pruritus affects a large part of the population, its reliable assessment remains difficult. Electronical diaries (eDiaries) are often used in multicentre clinical trials. The ItchApp© for Android was developed to assess itch intensity and course and was validated for the German language in 2017. Objective To validate ItchApp© for the use in the Polish and US English languages. Methods Fifty‐three subjects in Poland and thirty subjects in the USA with chronic pruritus completed the paper‐based and app‐based questionnaires. These questionnaires contained items for measuring the itch intensity, including a numerical rating scale (NRS) and verbal rating scale (VRS), and for detecting the change of pruritus since the beginning of treatment. Results The ItchApp© showed a high level of test–retest reliability [Intraclass correlation, Kappa and Kendall‐Tau B coefficients: 0.915–1.000 (Poland) and 0.863–1.000 (USA)]. The convergent validity showed strong correlation between the itch intensity scales on the ItchApp© (Items II‐IV = VRS mean, NRS mean and NRS worst) and the paper‐based itch intensity scales (mean and worst: VRS, NRS, VAS) [Spearman‐Rho and Pearson correlation coefficients: 0.710–0.987 (Poland) and 0.646–0.954 (USA)]. The ItchApp© items moderately correlated with the ItchyQol scores [Spearman‐Rho and Pearson correlation coefficients: 0.303–0.554 (Poland) and 0.275–0.447 (USA)]. After completing the ItchApp© questionnaire, a feasibility questionnaire was completed and showed that subjects feel the app is well suited for assessing pruritus. Conclusion We provide evidence for the ItchApp© as a validated eDiary for the assessment of pruritus in Polish and US English languages, enabling its use in multicentre international clinical trials.