Rivastigmine. A pharmacoeconomic review of its use in Alzheimer's disease

Alzheimer's disease is associated with a large cost burden, of which institutionalised care constitutes a major component. Therefore, the decision to move a patient from the community to institutionalised care is associated with a significant increase in direct costs. About three-quarters of patients with Alzheimer's disease are admitted to a nursing home within 5 years of diagnosis. Unpaid or informal caregiver time is another large cost in Alzheimer's disease, especially for patients cared for in the community; informal care can account for up to three-quarters of healthcare costs in non-institutionalised patients. Several cholinesterase inhibitors, of which rivastigmine is one, are available for the treatment of patients with mild to moderate Alzheimer's disease. By improving cognitive function and slowing the rate of cognitive decline, cholinesterase inhibitor therapy may reduce a significant part of the economic burden of the disease by delaying the move to institutionalised care. In the absence of prospective long term data which focus on pharmacoeconomic end-points, modelling techniques have been used to extrapolate clinical data available for some cholinesterase inhibitors, including rivastigmine. Four economic analyses, based on a single model of cognitive decline, have been performed with rivastigmine from the perspective of the provider or society. All show that rivastigmine therapy (excluding drug-related costs) is associated with cost savings in patients with mild to moderate Alzheimer's disease by delaying the time to institutionalisation. If the acquisition cost of the drug was factored in, the cost savings completely or partially offset treatment costs. The magnitude of the cost savings increased as the time horizon increased (up to 2 years). The largest savings were realised in patients with mild disease over a 2-year time-frame, suggesting that treatment should be initiated early from an economic viewpoint. Pharmacoeonomic data comparing different cholinesterase inhibitors are, as yet, unavailable.

Pharmacoeconomic analyses, based on modelled data excluding drug costs, indicate that rivastigmine completely or partially offsets the costs of treatment by delaying cognitive decline and the time to institutionalisation in patients with mild to moderate Alzheimer's disease. From a societal perspective, cost savings are realised if the drug is introduced early in the disease. Additional benefits offered by rivastigmine on behavioural symptoms, which may reduce caregiver burden, have yet to be investigated from a pharmacoeconomic perspective.