Assessment of health economics in Alzheimer's disease (AHEAD) based on need for full-time care

Objective: To develop a framework for estimating the long-term health and e conomic consequences of AD based on patient characteristics at a given poin t in time. Methods: A pharmacoeconomic model (Assessment of Health Economic s in Alzheimer's Disease, AHEAD) was developed based on equations that rela te the probability of needing full-time care (FTC) over time to patient cha racteristics summarized in index scores. These equations were developed fro m published data on interquartile times until FTC is needed and until death , using nonlinear regressions of the resulting index-specific hazards. Thes e equations were then incorporated into a hidden Markov framework that allo ws for calculation of expected time to FTC and to death, as well as of the economic consequences of disease progression. There are three major states in the model: not requiring FTC ("pre-FTC"), requiring FTC, and death. Resu lts: Outcomes for five sample patients are derived to illustrate applicatio n of the AHEAD model. The impact of altering disease markers in these patie nts is also considered. Conclusion: The need for a generally applicable too l to forecast long-term outcomes based on relatively short-term data is bec oming increasingly acute with the advent of new therapies for AD. The AHEAD model provides a relatively simple framework for the prediction of time to FTC requirement based on short-term observed data such as those from clini cal trials. Although subject to the uncertainties inherent in modeling, the model nevertheless provides a standard estimation technique that may facil itate comparisons between existing and emerging therapies.