Modelling the cost effectiveness of cholinesterase inhibitors in the management of mild to moderately severe Alzheimer's disease

Abstract

Objective: To estimate the cost effectiveness (from the UK NHS and personal social services perspective) of the cholinesterase inhibitors donepezil, rivastigmine and galantamine compared with usual care in the treatment of mild to moderately severe Alzheimer's disease. Patients had a mean age of 74 years, a mean disease duration of 1 year and a mean Alzheimer's disease assessment scale-cognitive subscale score of 24.

Methods: A pharmacoeconomic model was used to predict long-term outcomes over a 5-year time horizon and to estimate the cost effectiveness of cholinesterase inhibitors for the management of Alzheimer's disease. The model structure is informed by a systematic review of the literature on the clinical and cost effectiveness of cholinesterase inhibitors and a review of the literature on the costs and outcomes associated with treatment for Alzheimer's disease. The main outcome measure used was the cost per quality-adjusted life-year (QALY) gained. All healthcare costs (excluding cholinesterase inhibitor costs) were indexed to pounds sterling (2003 values). Drug costs are 2005 values. Multivariate probabilistic sensitivity analysis and scenario analysis were undertaken to assess uncertainty in the results.

Results: The clinical benefits on cognition from treatment with cholinesterase inhibitors resulted in an incremental cost per QALY gained ranging from 53,780 pounds sterling to 74,735 pounds sterling, over 5 years (vs usual care). Uncertainty analysis suggests that the probability of any of these treatments having an incremental cost per QALY of < 30,000 pounds sterling is < 21%. The key determinants of cost effectiveness were the effectiveness of treatment, the mean treatment cost and the cost savings associated with an expected delay in disease progression.

Conclusions: Results presented in this paper suggest that the use of cholinesterase inhibitors may not be a cost-effective use of NHS resources. Guidance from the National Institute for Health and Clinical Effectiveness (NICE) in the UK on their judgements surrounding the acceptability of technologies as an effective use of resources, indicates there would need to be special reasons for accepting cholinesterase inhibitors as a cost-effective use of NHS resources.