Delayed ATTR-CM diagnosis adds to annual healthcare spending, study finds

Patients who had a delayed diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CM) had higher healthcare utilization, which resulted in higher pharmacy spending and both inpatient and outpatient spending, according to a poster presented at the April 2026 AMCP annual meeting in Nashville.

Transthyretin amyloid cardiomyopathy (ATTR-CM) is a type of heart failure. It is a rare disease that leads to a buildup of the transthyretin (TTR) in the left ventricle, the heart’s main pumping chamber. Transthyretin is a protein that helps transport thyroxine, which regulates the metabolism and retinol in the body, but when it accumulates in the left ventricle, it thickens and stiffens the heart muscle. That thickening causes shortness of breath and heart failure. Other symptoms include swelling in the lower legs, chest congestion, increased heart rate and heart palpitations.

It is estimated that in the United States approximately 120,000 people have ATTR-CM. But the incidence and prevalence of ATTR-CM are increasing. A study published in January 2025 in the Journal of Cardiac Failure found that both incidence and prevalence increased, especially for older people, and more men were diagnosed with the disease than women.

Researchers from the University of Texas at Austin College of Pharmacy and Baylor Scott & White Medical Center wanted to identify the proportion of patients with a delayed diagnosis among patients who had been treated with tafamidis, which is marketed as Vyndamax. Developed by Pfizer, Vyndamax was approved by the FDA in May 2019. Researchers want to compare the differences in healthcare resource utilization among those with and without treatment delay.

Researchers said ATTR-CM is often mistaken for other cardiac conditions, such as hypertrophic cardiomyopathy, hypertensive heart disease or aortic stenosis. They cite previously-published research showing that between 34% and 57% of patients receive an initial diagnosis other than ATTR-CM and diagnostic delays result in great disease severity.

Led by Beverly Fuerte, Pharm.D., a postdoctoral fellow in health economics and outcomes research, researchers conducted a retrospective cohort study of Merative MarketScan commercial claims and Medicare supplemental claims between Jan. 1, 2018, and Dec. 31, 2022.

A total of 505 patients were treated with Vyndamax during this time frame. Because claims data did not include diagnostic tests, pharmacy claims for Vynadamax were used as a surrogate to indicate a confirmed diagnosis. Of those who had been treated, 277 patients had received delayed treatment, which researchers defined as 1 or more inpatient or 2 or more outpatient diagnoses of cardiac conditions that are considered differential diagnoses of ATTR-CM.

Across both Medicare and commercial patients, an initial diagnosis was heart failure and hypertensive heart disease. Among those with delayed treatment with Vyndamax, the leading cause of hospitalization was hypertensive heart disease, ischemic heart disease and cardiac arrhythmias.

Women were more likely to have a delayed diagnosis of ATTR-CM. Some patient characteristics were associated with increased risk of delayed diagnosis, including the presence of diabetes, liver disease and renal disease.

Average annual spending was higher for patients who had a delay in diagnosis. Annual pharmacy spending for those patients who had a treatment delay was $7,665 compared with $6,607 for those without a delay in treatment. Total outpatient costs for those with delays were $26,098 compared with $20,659; for inpatient spending, they were $19,783 for those with delays and $14,454.

Patients with delayed diagnoses also pay more out of pocket, including $522 for annual pharmacy spending (compared with $369 for no delays) and $1,190 for outpatient spending (compared with $993). But inpatient spending for those delayed diagnoses was lower, $291 compared with $420 for those with no delays.