To the Editor In their recent article 鈥淐ost-effectiveness of Aducanumab and Donanemab for Early Alzheimer Disease in the US,鈥� Ross et al¹ provide much needed insights into an important question given the potentially large treatment-eligible population and the expected budget impact of an Alzheimer treatment. However, their analysis has several methodologic flaws that may lead them to understate the value of such treatments.

First, their decision to include the cost of diagnosing patients is inconsistent with standard practice of cost-effectiveness analysis, which starts with diagnosed patients. Otherwise, the value of a treatment gets intertwined with the nature of the diagnostic process, which would probably render many treatments too costly. Second, they overstate the cost of aducanumab by assuming treatment to continue until severe dementia, which would be outside of the drug鈥檚 label, and by assuming full treatment adherence, which is not likely in real-world settings and inconsistent with their (correct) decision to regard patients who terminated treatment as part of the intervention group.