Abstract
IMPORTANCE: Timely diagnosis of transthyretin cardiac amyloidosis (ATTR-CM) is critical for early treatment to reduce morbidity and mortality, yet the timeliness of contemporary ATTR-CM diagnosis remains poorly understood. OBJECTIVE: To describe the time from incident heart failure (HF) diagnosis to ATTR-CM diagnosis and identify predictors of delayed diagnosis among Medicare beneficiaries. DESIGN, SETTING, AND PARTICIPANTS: This was a cohort study using US Medicare fee-for-service data from January 2016 to December 2022. Medicare fee-for-service beneficiaries with HF and ATTR-CM were included. Data were analyzed from November 2024 to July 2025. EXPOSURES: HF diagnosis with ATTR-CM diagnosis following HF diagnosis or within 1 year prior. MAIN OUTCOMES AND MEASURES: The primary outcome was time to ATTR-CM diagnosis, measured as the number of days between each patient's first HF diagnosis and first ATTR-CM diagnosis. Multivariable logistic regression assessed demographic, clinical, and socioeconomic factors associated with delayed ATTR-CM diagnosis (defined as >6 months from HF diagnosis to ATTR-CM diagnosis). RESULTS: A total of 7770 patients with HF and ATTR-CM were identified in the Medicare dataset. The median (IQR) age at the time of ATTR-CM diagnosis was 81 (76-86) years; 5995 enrollees (77%) were men. The median (IQR) time from HF diagnosis to ATTR-CM diagnosis was 494 (63-1340) days. For the 6175 patients with a loop diuretic prescription before ATTR-CM diagnosis, the median (IQR) time between initial loop prescription and ATTR-CM diagnosis was 840 (252-1768) days. After adjustment, older age (odds ratio [OR], 0.68; 95% CI, 0.63-0.74), history of atrial fibrillation (OR, 0.39; 95% CI, 0.33-0.49), and carpal tunnel syndrome (OR, 0.85; 95% CI, 0.74-0.97) were associated with lower odds of delayed diagnosis. Female sex (OR, 1.28; 95% CI, 1.13-1.45), a history of aortic stenosis (OR 1.39; 95% CI, 1.20-1.62), chronic obstructive pulmonary disease (OR, 1.18; 95% CI, 1.03-1.34), coronary artery disease (OR, 1.26; 95% CI, 1.13-1.40), diabetes (OR, 1.21; 95% CI, 1.07-1.37), and hypertension (OR, 1.28; 95% CI, 1.13-1.45) were associated with higher odds of delayed diagnosis. CONCLUSIONS AND RELEVANCE: There were substantial delays between incident HF and diagnosis of ATTR-CM found in this study. Female sex and having a history of aortic stenosis, coronary artery disease, diabetes, hypertension, or chronic obstructive pulmonary disease, which are each associated with cardiomyopathy and breathlessness, were associated with delayed diagnosis. These findings highlight the need for a heightened index of suspicion for ATTR-CM in patients with other possible etiologies of cardiomyopathy or HF symptoms.