Health economic effect of donepezil treatment for CDR 0.5 converters to Alzheimer's disease as shown by the Markov model

The previous health economic simulation of donepezil based on the Markov model revealed the treatment for mild to moderate stage of Alzheimer disease (AD) to be cost-effective. Our aim was to examine the economic effect of donepezil treatment for mild cognitive impairment, from which about 15% convert to dementia per year. We constructed a new Markov model using three simulations. Namely, Simulation A hypothesized that mild AD patients, i.e., Clinical Dementia Rating (CDR) 1, received donepezil as in the previous study. Simulation B hypothesized that all CDR 0.5 subjects received donepezil, and Simulation C considered that only the CDR 0.5 converters to dementia received donepezil. We calculated the models as follows: Simulation B, supposes that the annual transition probabilities were reduced even from 15% to 10% by donepezil, however, the drug had a negative economic effect. By contrast, in Simulation C, the annual transition probability was reduced from only 15% to 12% by donepezil, there was a positive economic effect. Since it is necessary to reduce the annual transition probability from 15% to 12% in order to manifest a concomitant economic benefit, we consider that early detection of CDR 0.5 converters in the community is important for health policy planning.