Prevalence, clinical characteristics and the burden of disease of the Croatian adult patients with HAE: nationwide survey analysis

<b>Background</b>. Hereditary angioedema (HAE) is a rare genetic disorder with variable prevalence, characterized by recurrent swelling in various parts of the body, including potential laryngeal attacks, significantly affecting patients' quality of life. <b>Methods</b>. A nationwide, cross-sectional survey study was conducted between December 2023 and June 2024, targeting adults (aged 18 and older). The patients filled out different HAE-related questionnaires. Descriptive statistics were used to analyze and summarize the data. <b>Results</b>. The prevalence of HAE in Croatia is estimated to be 3.10 per 100,000 people. The majority were females, patients with positive family history, and type 1 HAE. The median diagnostic delay was 13 years, with initial attacks typically occurring in adolescence, but diagnosis was often not established until young to middle adulthood. Regarding quality of life, approximately 51% reported a significant impact. Fatigue was prevalent, with 46.9% of patients experiencing mild to moderate levels, and 22.4% suffering from severe fatigue. Most patients reported minimal depression, and 37.7% presented with moderate to severe anxiety. Among employed individuals, a median presenteeism of 20% indicated productivity loss while at work, in contrast to generally minimal absenteeism. <b>Conclusions.</b> Recent more substantial diagnostic efforts and increased awareness are contributing factors to the higher observed prevalence of HAE in Croatia, mainly due to the sustained work of a dedicated patient organization and a well-developed network of national HAE experts. Patients still experience a high disease burden, impaired quality of life, and difficulties with daily activities, which trends also observed in other HAE cohorts worldwide.