Validity and Responsiveness of Urticaria Activity and Impact Measure (U-AIM), a New Patient-Reported Tool to Assess Disease Activity and Impact in Patients with Chronic Spontaneous/Idiopathic Urticaria (CSU/CIU)
Saturday, March 3, 2018
South Hall A2 (Convention Center)
Marcus Maurer, MD, Evgeniya N. Antonova, PhD, MS, Susan D. Mathias, MPH, Ross D. Crosby, PhD, James L. Zazzali, PhD, MPH
RATIONALE: The 7-day urticaria activity score (UAS7), the gold standard for assessing disease activity in CSU/CIU patients, requires prospective data collection. We developed a retrospective 9-item Urticaria Activity and Impact Measure (U-AIM; 7-day recall) and examined its measurement properties. U-AIM evaluates itch, hives, angioedema, their bother, interference with sleep and daily activities, and urticaria control.

METHODS: Analyses used an open-label data cut from a 24-week open-label single-arm period of XTEND-CIU – a randomized, double-blind, placebo-controlled trial, which enrolled ≥12-year-old CSU/CIU patients (n=206, 75% female, mean age 44.6 years), symptomatic despite standard treatments. XTEND-CIU measured U-AIM and UAS7. We evaluated U-AIM items factor structure, validity (convergent, known-groups), response characteristics, clinically meaningful change (CMC), and responsiveness.

RESULTS: At baseline, patients reported prevalent severe itch (55%) and >12 hives (67%), angioedema (15%), and bother by itch (84%), hives (84%), and angioedema (49%). Exploratory factor analysis and clinical judgment suggested individual item scoring. U-AIM itch and hives items and UAS7 equivalents produced strong correlation coefficients (itch severity: 0.634–0.806; hives number: 0.735–0.843; UAS7 proxy: 0.724–0.852). Changes in U-AIM scores differentiated patients by their perspective of symptoms improvement: mean change in itch severity was -2.16 (very much improved), -1.64 (much improved) and -0.71 (minimally improved). CMC for improvement ranged 0.80–1.00 (itch severity and hives number) and 10.5–12.5 (UAS7 Proxy). All items demonstrated adequate response characteristics and responsiveness.

CONCLUSIONS: U-AIM is valid and responsive to change. CMC estimates for itch, hives, UAS7 are available. U-AIM may help clinicians monitor CSU/CIU symptoms and impact and track treatment effectiveness.