Abstract Body (Do not enter title and authors here): Objective: Transthyretin amyloid cardiomyopathy (ATTR-CM) is a progressive heart disease caused by deposited amyloid fibrils, leading to stiffening of the heart muscle. Due to the absence of validated algorithms identifying ATTR-CM in claims data, limited evidence exists on healthcare resource utilization (HCRU) and costs in this population. Following the approval of tafamidis in 2019, a first-in-class therapy for ATTR-CM, this study aimed to estimate HCRU, medical spending, and assess the impact of key covariates on cost among patients who initiated tafamidis.

Methods: We conducted a retrospective cohort study using Merative MarketScan^® Commercial Claims and Medicare Supplemental Database (2019-2021). We identified adult patients initiating tafamidis using the national drug codes and followed them until disenrollment. Patients were required to be continuously enrolled for 3 months prior to the index date, defined as the first tafamidis prescription. Outcomes included all-cause, cardiovascular (CV)-related, and neuropathy (NP)-related annualized medical spending and HCRU, including hospitalization, length of stay (LOS), and emergency department (ED). Out-of-pocket spending and quarterly trends were also evaluated. A generalized linear model with log link and gamma distribution was used to estimate the marginal effects of covariates on cost.

Results: The study cohort included 346 tafamidis users; 79% were male, and 64% were aged ≥75. Mean annual all-cause healthcare spending was $295,434 (95% CI: $274,742–$316,126), with out-of-pocket costs of $4,315 ($3,517–$5,113). Tafamidis accounted for 76% of total spending, while CV- and NP-related costs made up 6.9% and 3.4%, respectively. Patients averaged 0.69 all-cause and 0.27 CV-related hospitalizations per year, with lengths of stay of 6.48 and 6.69 days, respectively. ED visits occurred every 17 months (all-cause) and every 174 months (CV-related), with no NP-related ED visits. Quarterly spending peaked after tafamidis initiation and declined over time, driven by pharmacy costs. Annual spending was 13% lower among patients ≥75, averaging $40,428 less than those <75, though this difference was not significant (β = -0.137, p = 0.0682).
Conclusions: Patients with ATTR-CM treated with tafamidis incurred substantial medical costs, largely driven by drug spending. However, the out-of-pocket burden remained relatively low, with most costs covered by payers.