On-demand treatment of hereditary angioedema attacks: Patient-reported utilization, barriers, and outcomes

Background: Hereditary angioedema (HAE) is clinically characterized by recurrent attacks of subcutaneous and submucosal swelling. Objective: To investigate real-world timing, potential barriers, and impact of delaying on-demand treatment (OD) of HAE attacks. Methods: Patients with HAE (type I or II) aged 12 years or older with more than or equal to 1 treated (Treated Cohort) or untreated (Untreated Cohort) attack in the past 3 months were recruited by the US HAE Association. Respondents completed a 20-minute, self-reported, online survey about their last HAE attack. Results: In the Treated Cohort (n = 94), of the 67% who reported treating their attack early, only 26% administered OD in less than 1 hour. Furthermore, 79% (n = 74) reported treatment-related anxiety, which correlated with treatment delay. Time to treatment paralleled changes in attack severity (33% mild attacks treated in <1 hour vs 67% in ≥1 hour, progressed to moderate/severe) and mean duration (<1 hour: 0.7 day; >8 hours: 2.7 days). In the Untreated Cohort (n = 20), 50% of the respondents describing their last untreated attack as mild experienced progression to moderate or severe and 25% reported spread to another site including the larynx and face. Untreated attacks lasted a mean of 2.3 days. Conclusion: The disparity between survey respondents’ perception of treating early and actual time to OD administration is striking. Treatment-related anxiety was a common reason for delaying OD. Increased treatment intervals translated into progression of HAE attack severity, duration, and spread to other sites. Suboptimal management of attacks intensifies the HAE disease burden, underscoring the need for improved treatment options, guidance, and removal of OD administration barriers.