EQ-5D utilities in chronic spontaneous/idiopathic urticaria
Objectives To obtain utility estimates suitable for use in economic models for chronic spontaneous (idiopathic) urticaria (CSU). Methods Patient-level data from three randomized clinical trials—ASTERIA I, ASTERIA II and GLACIAL—were analysed. Health states were derived from the Urticaria Activity Score over 7 days (UAS7); higher scores denote greater activity. The health state score ranges were urticaria free: 0; well-controlled urticaria: 1–6; mild urticaria: 7–15; moderate urticaria: 16–27; and severe urticaria: 28–42. The mean EQ-5D utilities were calculated for each health state. A mixed model was used to predict the EQ-5D according to UAS7 health states in a pooled data set containing all treatment arms and time points from the three trials. Pooled trial data were validated through visual comparisons and interaction terms. Fixed and random effects for trials and patients were included, along with the following covariates: UAS7 health state at baseline (moderate or severe); presence of angioedema at baseline and during follow-up; duration of CSU; number of previous CSU medications; visit; current treatment; and patient age and sex. Results There was a consistent improvement in EQ-5D utilities as urticaria activity decreased. The mean utilities ranged from 0.710 (severe urticaria) to 0.780 (moderate urticaria), 0.829 (mild urticaria), 0.862 (well-controlled urticaria) and 0.894 (urticaria free). Sensitivity and subgroup analyses confirmed the robustness of the results. Conclusion The results suggest that EQ-5D utility scores increase with decreasing urticaria activity. EQ-5D utility scores enable the health-related quality of life of CSU patients to be compared with that of patients with other diseases.