Validity, reliability, and interpretability of the Brazilian urticaria control test.

Abstract

Background: The urticaria control test (UCT) is a patient-reported outcome measure designed to determine the current level of disease control in patients with chronic urticaria (CU). Recently, a Brazilian UCT was developed, but its validity and reliability are unknown. Method: The clinimetric properties of the Brazilian UCT short form (UCTsh) and its long form (UCTlg) were determined in 130 patients with CU. In parallel, the urticaria activity scores (UAS) that covers 7 days (UAS7) and 28 days (UAS28) were used to assess disease activity. Subsequently, the results were analyzed statistically to determine the validity, reliability, and interpretability of the Brazilian UCT versions. Results: A total of 107 female (82%) and 23 male patients with CU completed both versions of the Brazilian UCT. Both of the Brazilian UCT versions showed excellent internal consistency reliability. In addition, the Brazilian UCT results showed strong correlations with UAS7 and UAS28 results, which indicated high levels of convergent validity. The test-retest reliability was examined in a subsample of 27 patients with CU and was found to be excellent. Notably, the results of both Brazilian UCT versions correlated extensively, which suggested that the UCTsh can replace the UCTlg without changing the UCT results. Conclusion: The Brazilian UCT is a valid and reliable tool for assessing disease control. To facilitate the use of the Brazilian UCT in global studies and to put a stronger focus on the specificity, we propose that the same cutoff values for well-controlled disease should be used as identified in the original publication of the UCT, i.e., ≥12 points for the UCTsh.