Objectives: The aim of this study was to develop a Spanish version of the Chronic Urticaria Quality of Life Questionnaire (CU-Q2oL) and to test its acceptability, reliability, validity, and sensitivity to change.
Methods: Forward and back translation by bilingual translators followed by pilot testing in patients with urticaria was used to adapt the questionnaire. The Spanish version of the CU-Q2oL was self-administered alongside the Skindex-29 in an observational, longitudinal, multicenter study. Feasibility was assessed by analyzing missing responses and ceiling and floor effects. Reliability was tested by examining internal consistency (Cronbach alpha). Construct validity was analyzed by examining convergent and discriminant validity with the Skindex-29 and by evaluating the ability of the CU-Q2oL to discriminate between patients according to a clinical classification of severity. Sensitivity to change was analyzed in a subgroup of patients who completed a second visit 4 weeks after baseline.
Results: A total of 695 patients were included in the analysis. Mean (SD) age was 42.4 (15.0) years and 62.1% of the sample was female. All of the items on the CU-Q2oL were answered by 91.9% of the sample. Over 15% of patients scored at the floor (best possible health) on 5 of the 6 dimensions. Cronbach alpha coefficients were > 0.80 for all dimensions of the CU-Q2oL, and 0.86 for the overall score. Construct validity was supported by correlations between the CU-Q2oL and the Skindex-29, which generally fulfilled hypotheses, and by the questionnaire's ability to discriminate between groups with different severities of urticaria.The questionnaire was sensitive to change, with an effect size of 1.0 for the overall score in patients reporting an improvement on the health transition scale.
Conclusions: The Spanish version of the CU-Q2oL has shown satisfactory reliability, validity, and sensitivity to change. It is suitable for use as an outcome measure for chronic urticaria patients in clinical and research settings.