Modeling the Cost and Health Impacts of Diagnostic Strategies in Patients with Suspected Transthyretin Cardiac Amyloidosis

Abstract

BACKGROUND: Transthyretin cardiac amyloidosis (ATTR-CMP) is an increasingly recognized and treatable cause of heart failure with preserved ejection fraction. Multimodality cardiac imaging is recommended for ATTR-CMP diagnosis, but its cost-effectiveness in current clinical practice has not been well studied. METHODS AND RESULTS: Using a microsimulation model, we compared the cost-effectiveness of a combination of strategies involving99m technetium pyrophosphate (PYP), cardiac magnetic resonance imaging, and endomyocardial biopsy for the diagnosis of ATTR-CMP. We developed a decision analytic model to project health care costs and lifetime quality-adjusted life years for symptomatic, older patients who present with congestive heart failure, with an increased left ventricular wall thickness and a 13% prevalence of ATTR-CMP. Rates of clinical events, costs, and quality-of-life values were estimated from published literature. The analysis was conducted from a US health care system perspective with health and cost outcomes discounted annually at 3%. In the base-case scenario, using a fixed tafamidis price of $16 000 annually (previously identified cost-effective price), total health care costs per person were lowest for the PYP-only strategy ($209 415) and highest for endomyocardial biopsy strategy ($215 881). Of the 7 strategies examined, the PYP-only strategy had the highest net monetary benefit using a willingness-to-pay threshold of $100 000/quality-adjusted life year. Results were sensitive to variations in model inputs for PYP and cardiac magnetic resonance imaging specificity, cost of tafamidis, and willingness-to-pay thresholds. CONCLUSIONS: Our model-based analyses showed that a PYP-only strategy to diagnose ATTR-CMP is the most cost-effective strategy, at willingness-to-pay threshold of $100 000/quality-adjusted life year. At higher threshold ($150 000/quality-adjusted life year), sequential tests involving PYP and cardiac magnetic resonance imaging may be considered cost effective. © 2022.