The Assessment of Health Economics in Alzheimer’s Disease (AHEAD) decision analytic Markov model was used (Caro, et al. 2001, see 'Other Publications of Related Interest' below for bibliographic details). This model was adapted to a South Korean setting. The time horizon was five years and the authors reported that the perspective was that of the third-party payer.
The clinical data were identified by a literature review and the search strategy, including the key terms, was reported. The review included citation searches for further studies. The clinical and epidemiological data from Korean studies were favoured over those from studies in other settings. When no Korean data were found, the authors used those most frequently quoted in publications. The main effectiveness estimate was the proportion of patients in full-time care after one year of treatment and this was from a Korean study (Suh, et al. 2008, see 'Other Publications of Related Interest' below for bibliographic details).
Monetary benefit and utility valuations:
The utilities were from published data (Neumann, et al. 1999, see 'Other Publications of Related Interest' below for bibliographic details) that evaluated quality of life in patients with Alzheimer’s disease.
Measure of benefit:
Quality-adjusted life-years (QALYs) gained were the measure of benefit and they were discounted at 1.5% per annum.
The direct costs were those associated with hospital and primary care services (in-patient, out-patient, day hospital, emergency room, community mental health centre, general practitioner, community practice nurse, and medications); social care services (social worker, day care centre, meals on wheels, and home care); accommodation; and out-of-pocket expenses, such as home help and vitamin supplements. Productivity costs were calculated using a replacement cost approach. Caregiver time was calculated using the caregiver time section of the Resource Utilization in Dementia questionnaire. The resource use data were from a one-year prospective trial, undertaken in South Korea (Suh, et al. 2008). The unit costs were from South Korean sources. All costs were updated to 2007 prices, using the consumer price index, and future costs were discounted at a rate of 6%. The currency was the US dollars ($).
Analysis of uncertainty:
A probabilistic sensitivity analysis was undertaken, by assigning distributions to the model parameters. The parameter values were drawn at random from each distribution, using 1,000 Monte Carlo simulations. The results of the probabilistic sensitivity analysis were presented in a cost-effectiveness acceptability curve and scatter plots. A series of one-way sensitivity analyses were also undertaken.