# Epidemiological and clinical characteristics of hereditary angioedema in the Baltic states

## TL;DR

This study examines the prevalence, diagnosis, and treatment of hereditary angioedema in Estonia, Latvia, and Lithuania, finding significant regional differences.

## Contribution

The study provides the first detailed epidemiological and clinical analysis of hereditary angioedema in the Baltic states.

## Key findings

- Estonia had the highest HAE point prevalence (2.19 per 100,000) and shortest diagnostic delay (9.5 years).
- Latvia had the lowest prevalence (0.65 per 100,000) and longest diagnostic delay (24 years).
- SERPING1 gene pathogenic variants were most common across all three countries.

## Abstract

Hereditary angioedema (HAE) is a rare, potentially life-threatening disorder characterised by recurrent episodes of localised oedema caused by bradykinin overproduction. Accurate epidemiological data are essential for optimising diagnosis and treatment, particularly in underrepresented regions such as the Baltic states. This study aimed to examine the prevalence, clinical characteristics, genetic variants, and treatment accessibility for patients with HAE in the Baltic states of Estonia, Latvia, and Lithuania.

This retrospective study included HAE patients diagnosed according to the WAO/EAACI 2021 criteria between 2004 and 2024. Demographic, clinical, and genetic data were collected and evaluated. Descriptive statistical analysis was performed using Jamovi (version 2.3).

A total of 78 patients were identified in Estonia (n=30), Latvia (n=12) and Lithuania (n=36) from 2004 till 2024. In Lithuania, 7 patients had died and 3 were lost to follow-up, resulting in 26 patients remaining under active observation. While the total number of HAE cases identified across the three countries was reported, detailed clinical data and analyses were limited to the 68 patients who were alive and actively followed at the time of data collection. Estonia exhibited the highest point prevalence (2.19 per 100, 000), while Latvia had the lowest (0.65). The median diagnostic delay was longest in Latvia (24 years) and shortest in Estonia (9.5 years). SERPING1 gene pathogenic variants predominated. Estonia had the broadest availability of treatments, whereas Latvia had restricted access to modern therapies.

Considerable variation exists in HAE prevalence, diagnosis, and treatment across the Baltic states. Estonia exemplifies best practices, while Latvia remains underserved. Regional collaboration and standardised care protocols are urgently needed.