Disparities in chronic spontaneous urticaria: Eligibility for drug reimbursement associated with clinical outcomes

Abstract

BackgroundChronic spontaneous urticaria (CSU) is an immunological condition with an estimated prevalence of 0.1%. For poorly controlled CSU despite antihistamines, omalizumab is the only treatment approved and recommended by international guidelines. ObjectiveTo outline the impact of treatment accessibility on CSU outcomes in the real world. MethodsSerial data of adult CSU patients receiving care of at least 6 months at a dedicated, immunologist-led Urticaria Clinic at Grantham Hospital in Hong Kong between 2018 and 2023 were analysed. Their clinicodemographic data, drug eligibility status (eligible for reimbursement or not), treatment step, and disease activity (weekly Urticaria Activity Score [UAS7]) were collected and compared according to drug eligibility status. ResultsThis study included 238 patients, 80 (33.6%) of whom were eligible for reimbursement whereas 158 were not. No significant clinicodemographic differences including disease activity were found at baseline. At latest follow-up, significantly more patients in the eligible group were receiving omalizumab (28.7% vs 5.7%, p<0.001), equivalent to a multivariate odds ratio of 9.35 (95%CI=3.689-23.703, p<0.001). The discrepancy persisted even in patients with moderate-to-severe CSU whose UAS7≥16 (40.6% [13/32] vs. 10.2% [6/59], p<0.001). Besides, there was significantly less dose reduction (below 300mg every 4 weeks) in eligible omalizumab users (4.3% vs. 44.4%, p=0.015). Clinically, significantly greater improvements in UAS7 were reported by the eligible group (median change: -8.0 vs. -5.0, p=0.021). ConclusionPatterns of management varied largely among patients with different drug eligibility statuses and led to disparities in health outcomes. More efforts are warranted to secure equitable access to guideline-based CSU care.