Rare form of HAE may bring more frequent attacks, greater daily impact
Survey compares type 3 HAE with types 1 and 2 across symptoms and care needs
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People with type 3 hereditary angioedema (HAE) may report more frequent swelling attacks than people with HAE types 1 or 2, according to a new survey study.
The findings also suggest people with HAE type 3 may be more likely to experience potentially life-threatening throat swelling and to report worse health-related quality of life.
Overall, the researchers said the data suggest people with HAE type 3 “experience a significantly greater disease burden than those with HAE Type 1/2, emphasizing the need for improved diagnosis, targeted treatment strategies, and a deeper understanding” of the biology behind this rare type of angioedema.
The study, “Patient-reported disease burden and health care utilization of HAE-nl-C1INH: insights from a real-world survey,” was published in Clinical and Experimental Medicine.Â
How type 3 HAE differs from more common forms
HAE is a genetic disorder marked by recurring attacks of swelling. HAE types 1 and 2, the most common forms, are caused by mutations in the gene that provides instructions for making the C1-inhibitor protein. HAE type 3 — also called HAE with normal C1-inhibitor (HAE-nl-C1INH) — is a broader category that includes cases of HAE that are caused by mutations in other genes.
Because HAE type 3 is much rarer than types 1 and 2, it is less well understood. To better understand HAE type 3 and how it compares with more common forms, researchers conducted a survey of 89 people with HAE — 45 with type 3 and 44 with types 1 or 2.
In both groups, most participants identified as women and white. Demographics were similar between people with type 3 and types 1 or 2, as were treatment patterns and reported swelling triggers. Despite these similarities, people with type 3 tended to experience longer delays before diagnosis. Nearly one third (32%) of people with HAE types 1 or 2 were diagnosed by age 18, compared with only 4% of those with type 3.
Study finds higher attack rates and greater disease burden
Patients with type 3 HAE also reported more frequent swelling attacks. When asked about the previous three months, nearly half (47%) said they had multiple attacks per week, compared with 14% of patients with HAE types 1 and 2. In contrast, more patients with types 1 or 2 reported having fewer than one attack per month (32% vs. 11%).
Patients with type 3 HAE were also more than twice as likely to report orofacial-laryngeal swelling — swelling affecting the face, tongue, or throat — which can become life-threatening if it blocks the airway. People with type 3 HAE also reported more co-occurring health conditions, more frequent doctor’s visits, and worse quality-of-life scores.
“The findings from this cross-sectional survey underscore key differences in disease burden and patient experiences between individuals with HAE Type 1/2 and those with HAE-nl-C1INH. While demographic characteristics were similar across groups, participants with HAE-nl-C1INH exhibited significantly greater disease burden in terms of attack frequency, anatomical distribution of swelling, health care utilization, and overall” quality of life, the researchers concluded.
The researchers said the study “highlights the substantial burden experienced by patients with HAE-nl-C1INH compared with those with HAE Type 1/2.” They added that the findings “underscore the need for improved diagnostic and therapeutic strategies tailored to the severity and intensity of disease” and “highlight the importance of an improved understanding” of the prevalence and biology of type 3 HAE.
