Cost-effectiveness analysis of dopamine agonists in the treatment of Parkinson's disease in Japan

Background: Dopamine agonists such as bromocriptine or pergolide are often used in Japan to treat Parkinson's disease. Dopamine agonists are relativel y expensive drugs; economic evaluations are required. Objective: To evaluate the cost effectiveness of dopamine agonists for the treatment of Parkinson's disease in Japan. Design and setting: We used a Markov model to simulate the course of Parkin son's disease and to compare the cost effectiveness of dopamine agonists ad ded to levodopa with that of levodopa alone in Japan. The model assumed tha t 60-year-old men with Parkinson's disease in Hoehn-Yahr (HY) stages 2 to 5 using levodopa were administered dopamine agonists or continued on levodop a alone. The incremental cost effectiveness of dopamine agonists used for 1 0 years was then estimated. Study perspective: Societal. Main outcome measures and results: In the patients in HY stage 2, the incre mental cost effectiveness of dopamine agonists was 18 610 000 to 19 320 000 yen (Y) per quality-adjusted life-year (QALY) [$US172300 to $US178900/QALY ; 1998 values]. In patients in HY stage 3 or higher, the use of dopamine ag onists was dominant over levodopa alone mainly due to reduced cost for care . In sensitivity analyses, costs and effectiveness of dopamine agonists sig nificantly influenced the results. The use of a generic formulation of brom ocriptine was dominant over levodopa alone even in the patients with HY sta ge 2 disease. Conclusions: Dopamine agonists appear to be cost effective in advanced Park inson's disease, although their use is sensitive to the costs and effective ness of dopamine agonists. If factors discouraging the prescription of gene ric drugs in Japan were removed, the treatment of Parkinson's disease would become more cost effective.