Further validation and threshold determination of Brazilian-Portuguese version of the Chronic Urticaria Quality of Life Questionnaire (CU-Q2oL)

Chronic spontaneous urticaria (CSU) markedly affects quality of life (QoL), and this study evaluated the Brazilian-Portuguese Chronic Urticaria Quality of Life Questionnaire (CU-Q2oL) in 169 patients with CSU, examining its validity, correlations with established patient-reported outcomes, and clinically meaningful severity cutoffs. CU-Q2oL scores correlated strongly with the Dermatology Life Quality Index (DLQI), moderately with the Weekly Urticaria Activity Score (UAS7), and inversely with the Urticaria Control Test (UCT), and a data-driven four-tier severity model showed excellent discriminatory performance. These findings support the CU-Q2oL as a valid QoL instrument in CSU and suggest that the four-tier scoring system may improve clinical stratification and treatment planning.