Clinical phenotype and prognosis of real-world patients with wild-type transthyretin amyloid cardiomyopathy treated with tafamidis

Aims: Tafamidis reshaped the treatment paradigm in transthyretin amyloid cardiomyopathy (ATTR-CM) based on a phase-3 randomized controlled trial, but real-world data on its use remain limited. This study aimed to assess in a large, contemporary, real-world cohort of patients with wild-type ATTR-CM (ATTRwt-CM) (i) the clinical phenotype of patients receiving tafamidis, and (ii) the association of tafamidis with survival using propensity-matched observational data. Methods and results: Data of patients diagnosed with ATTRwt-CM (January 2017 to June 2023) from 19 Italian centres were analysed. A propensity score (PS) reflecting the likelihood of being treated with tafamidis for each patient was determined using four variables that were significantly different among the two groups: age, New York Heart Association (NYHA) class, National Amyloidosis Centre (NAC) stage and mineralocorticoid receptor antagonists (MRAs). The primary outcome was all-cause mortality. The study comprised 1556 ATTRwt-CM patients: 965 (62%) patients initiated on tafamidis by June 2023 and 591 (38%) patients never treated with disease-modifying therapy. Tafamidis-treated patients were older, exhibited a lower NYHA class and NAC stage, and were more often treated with MRAs compared to untreated patients. The PS-matched cohort comprised 426 patients treated with tafamidis and 426 PS-matched untreated patients (mean age 78.9 ± 5.0 years, 88.3% men, 12.9% in NYHA class III). Adequacy of matching was verified (standardized differences: <0.20 between groups). Over 25 months (interquartile range: 15–40), treatment with tafamidis was associated with lower rates of all-cause mortality (hazard ratio 0.55, 95% confidence interval 0.39–0.77, p = 0.001) across the spectrum of NAC disease stages (p-interaction = 0.94). Conclusions: In this large, contemporary, real-world cohort of patients with ATTRwt-CM, predominantly in NYHA class I or II, treatment with tafamidis was consistently associated with a significantly lower risk of all-cause mortality.