Background/Case Studies: Hereditary angioedema (HAE) is a rare, genetic condition treated with plasma-derived human C1 esterase inhibitor (C1-INH). Little is known about patient geographic distribution and patterns of use. The project aim was to understand how and where C1-INH product is being used to treat HAE in Canada.
Study
Design/Methods: An online survey using REDCap was distributed by email to hospitals that had received C1-INH from the blood supplier between Dec 2019 and Nov 2020. Hospital demographics, contact information and C1-INH use in-hospital and by patients at home was requested. Descriptive analyses were performed. Calculation of IUs of C1-INH from vial numbers used by hospitals was assumed to follow the national distribution of vial sizes (1500 and 500 IUs). Research Ethics Board approval was not required.
Results/Findings: Respondents: 83/181 hospitals (47.5%) that received C1-INH responded: 39 from Ontario; 35 from Alberta and British Columbia combined and 9 from other provinces. The 83 hospitals represented 52.3% of the C1-INH product distributed nationally. Patients: 221 patients received 1844 vials (2.6 million IUs) of C1-INH in a hospital setting: 138 in the emergency department (62.4 %), 53 as inpatients (24.0%), and 30 in out-patient clinics (13.6%). The total number of hospital patient encounters was 615 with the out-patient clinic having the highest proportion (52.5%). For home care use, 68 hospitals (81.9%) issued product to 239 patients; 67.8% were female. The most common age category was 30-44 years but in Ontario the age demographic was slightly older (45-59 years). Distribution and Use: The total number of C1-INH units issued to all hospitals in Canada was 62,260,000; of which 32,568,000 units were issued to the 83 responding hospitals. There were 2,616,000 IUs of C1-INH transfused in hospitals, 424,500 IUs transferred to other hospitals and 101,000 IU discarded. For home care, 31,395,000 IUs were transfused; hence, home care use accounted for 92% of product issued. Conclusions: This project gives a Canadian snapshot of the distribution and use of C1-INH both in hospitals, and at home for patients with HAE, with most patients residing in 3 provinces and the majority of product being used for home care. Further information is required to understand the proportion of home product used on-demand versus prophylactically.
Importance of research: C1-INH is an expensive product with over 62 million IUs distributed to Canadian hospitals each year. There is a paucity of information on patient population density and distribution and usage patterns of C1-INH, making it difficult to forecast future demand and budgets. This snapshot of distribution and utilization patterns can inform future discussions about a tracking system for the use of C1-INH.
