Presentation (CTI)

OBJECTIVES: Alzheimer’s disease (AD) is a form of dementia that progressively affects cognition, behavior, and functional status. Early detection and diagnosis of AD enables earlier access to treatment. Therefore, this study aimed to identify the most cost-effective diagnostic strategy (amyloid blood test [ABT], cerebral spinal fluid tap [CSF], amyloid positron tomography [aPET]) for AD from the US payer perspective.
METHODS: A Markov model was developed to simulate three cohorts of patients with AD and receiving ABT, CSF, or aPET testing. Assuming all patients enter in mild cognitive impairment (MCI) stage, progressive states of mild AD, moderate AD, severe AD, and death were considered. The cycle length was one year with a time horizon of 25 years. Inputs for the model included rates of state transition, cost of each state, cost of the diagnostic, and specificity (i.e., effectiveness among patients with AD) of each diagnostic. The model leveraged true positive rates for each diagnostic. A cost-effectiveness analysis (CEA) was conducted to assess the incremental cost-effectiveness ratio (ICER) and net monetary benefits (NMB) of the diagnostic strategies at a willingness-to-pay (WTP) threshold of $150,000. A sensitivity analysis was conducted with a +/-10% variation in all model inputs.
RESULTS: Without dominance, the ICER for aPET ($52,500) was higher than for CSF ($10,821) and it fell on the WTP threshold. NMB of aPET was the highest ($1,955,969) followed by CSF ($1,880,303) then ABT ($1,799,293). Thus, aPET was the most cost-effective diagnostic strategy. The time horizon and specificity were determined the most influential inputs on the NMB for all three diagnostic strategies.
CONCLUSIONS: aPET has greater effectiveness but at a higher cost compared to CSF and ABT. At the WTP threshold of $150,000, aPET was determined the most cost-effective diagnostic strategy for AD.