Cost-effectiveness of donepezil in the treatment of mild or moderate Alzheimer's disease.

Available treatments for Alzheimer's disease (AD) need to be evaluated in order to determine whether the clinical benefits justify their additional costs. This study evaluated the cost-effectiveness of donepezil treatment compared with no-drug treatment of mild and moderate AD from the perspective of society and the health care system in Spain. A Markov model was designed to simulate the natural history of a cohort of patients with mild and moderate AD. Monthly transition probabilities were estimated from the international literature and donepezil clinical trials. Direct medical and non-medical costs and utilities were derived from Spanish studies. Local data on tolerance and medication withdrawal rates were incorporated into the model. Incremental cost-effectiveness ratios for a range of realistic treatment options were calculated. A probabilistic sensitivity analysis was carried out using a Monte Carlo approach with 10,000 iterations. In the baseline scenario (24 months, patients initially with mild AD) incremental cost-effectiveness for direct medical costs was 20,353 euro/QALY. When all costs were taken into account, donepezil treatment was the dominant strategy. Incremental cost-effectiveness ratios vary according to the selected perspective. For the baseline scenario, donepezil treatment is cost-effective with a probability of 95% for a threshold efficiency of 25,000 euro/QALY.