Cost-effectiveness: cholinesterase inhibitors and memantine in vascular dementia.

BACKGROUND: Several randomized controlled trials of cholinesterase inhibitors and memantine in mild to moderate vascular dementia have demonstrated the efficacy of these treatments. However, given these drugs incur considerable cost, the economic argument for their use is less clear. OBJECTIVE: To determine the incremental cost-effectiveness of cholinesterase inhibitors and memantine for mild to moderate vascular dementia. DESIGN: A decision analysis model using a 24-28 week time horizon was developed. Outcomes of cholinesterase inhibitors and memantine and probabilities of adverse events were extracted from a systematic review. Costs of adverse events, medications, and physician visits were obtained from local estimates. Robustness was tested with probabilistic sensitivity analysis using a Monte Carlo simulation. INTERVENTIONS: Donepezil 5 mg daily, donepezil 10 mg daily, galantamine 16-24 mg daily, rivastigmine flexible dosing up to 6 mg twice daily, or memantine 10 mg twice daily versus standard care. MAIN OUTCOME MEASURES: Incremental cost-effectiveness ratio (ICER) expressed as cost per unit decrease in the Alzheimer's Disease Assessment Scale-cognitive (ADAS-cog) subscale. RESULTS: Donepezil 10 mg daily was found to be the most cost-effective treatment with an ICER of $400.64 (95%CI, $281.10-$596.35) per unit decline in the ADAS-cog subscale. All other treatments were dominated by donepezil 10 mg, that is, more costly and less effective. CONCLUSION: From a societal perspective, treatment with cholinesterase inhibitors or memantine was more effective but also more costly than standard care for mild to moderate vascular dementia. The donepezil 10 mg strategy was the most cost-effective and also dominated the other alternatives.