(316) Understanding the Prevalence of Transthyretin Amyloidosis (ATTR) in Europe: A Comprehensive Literature Review

Background: Transthyretin amyloidosis (ATTR) is a rare condition with scarce and inconsistent epidemiologic data. This study aims to provide a comprehensive overview of ATTR prevalence by clinical or genetic subtype in Europe.

Objectives: This study aims to provide a comprehensive overview of ATTR prevalence by clinical or genetic subtype in Europe.

Methods: A targeted literature search was conducted in PubMed and Orpha.net using key relevant words to identify articles from January 2009 until July 2023 reporting the epidemiology of ATTR in Europe. Filters limited the search to observational, human, and English language studies. Any studies without prevalence data or in non-European populations were excluded by manual review. All data were extracted, synthesized, and analysed by clinical (i.e., ATTR with cardiomyopathy [ATTR-CM] and ATTR with polyneuropathy [ATTR-PN]) and genetic subtypes (i.e., hereditary ATTR [ATTRv] and wild-type ATTR [ATTRwt]).

Results: The literature search yielded 265 articles. Nineteen full-text studies reporting the prevalence of ATTR overall and/or by subtype in Europe were included in this review: 11 from non-endemic European countries for the disease (2 ATTR-CM, 3 ATTR-PN, 4 ATTRv, 1 for overall ATTR), 7 from endemic countries (1 ATTR-CM [Sweden], 4 ATTR-PN [Cyprus, Portugal, Majorca in Spain, Sweden], 2 ATTRv) [Crete Island in Greece, Lazio in Italy, Norrbotten in Sweden], and 2 multinational studies assessing both endemic and non-endemic countries for the disease (1 ATTR-CM, 1 ATTR-PN).
ATTR-CM prevalence varied from 14 to 37 per 1,000,000 persons in non-endemic countries, after excluding studies limited to older (age >50 years) populations (50 in Sweden, an endemic country for the disease), while ATTR-PN ranged from 1.4 to 9.9 per 1,000,000 persons in non-endemic regions and higher in endemic areas (8.8 to 229.3). ATTRv prevalence in non-endemic countries ranged from 2.4 to 17.2 per 1,000,000 persons, with regional variations. Endemic regions exhibited a much higher prevalence (35.3 to 251.5). ATTRwt prevalence was estimated at 90.3 per 1,000,000 persons.

Conclusions: Improved understanding of ATTR epidemiology is necessary to facilitate earlier diagnosis and management of the disease. The current literature reports heterogenous results in the prevalence of ATTR across Europe, which might be partially explained by different study designs, targeted populations, and case definitions. While our results confirm that ATTR is a rare disease in Europe, even in endemic regions, it will be important to continue to estimate the prevalence of this disabling disease as awareness and diagnostic accuracy increase.