Prevalence, characteristics, and mortality of patients with transthyretin amyloid cardiomyopathy in the Nordic countries

AIMS: Transthyretin amyloid cardiomyopathy (ATTR‐CM) is a progressive condition caused by deposition of transthyretin amyloid fibrils in the heart and is associated with poor quality of life and a shortened lifespan. This study aimed to describe the prevalence, clinical characteristics, and mortality of patients with ATTR‐CM, using multiple national health registers in Denmark, Finland, Norway, and Sweden. METHODS AND RESULTS: Transthyretin amyloid cardiomyopathy patients were identified during 2008–2018 using a combination of diagnosis codes for amyloidosis and heart disease and were matched to patients with non‐ATTR heart failure (HF). An identical study design was used in each country to facilitate comparison and aggregation of results. A total of 1930 ATTR‐CM patients were identified from national health registers in the four countries. In 2018, prevalence of ATTR‐CM per 100 000 inhabitants ranged from 1.4 in Denmark to 5.0 in Sweden; a steep increase over time was observed in Sweden and Norway. Median survival from diagnosis was 30 months for ATTR‐CM patients and 67 months for matched HF patients. Survival was significantly lower for female than for male ATTR‐CM patients (median survival: 22 and 36 months), while no significant difference was observed in the HF cohort. CONCLUSIONS: This study provides the first nationwide estimates of the prevalence, clinical characteristics, and mortality of patients with ATTR‐CM, using identical study design across several countries. Findings corroborate previous case series showing high mortality in ATTR‐CM, two‐fold higher than for other HF patients and higher in women than men, highlighting the need for more precise and early diagnosis to reduce the disease burden.