Short-term cost and health consequences of duodenal levodopa infusion in advanced Parkinson's disease in Sweden: an exploratory study.

Levodopa is the cornerstone treatment for Parkinson's disease, but the short half-life of levodopa limits its usefulness in late stages of the disease. Duodenal levodopa infusion (DLI) allows more stable plasma levels and better motor symptom control. To explore the costs and health benefits of replacing conventional oral polypharmacy with DLI in patients with advanced Parkinson's disease, from a Swedish healthcare payer perspective. Based on a clinical, randomized, crossover study with 24 patients (DIREQT), a decision analytic model predicted 2-year drug costs and QALYs for conventional oral therapy and for DLI. Health-related quality of life (HR-QOL) was recorded using a 15-dimensional (15D) utility instrument at baseline and during the two 3-week trial periods, and then at eight follow-up visits during the subsequent 6 months. Use of medication was based on data from DIREQT and previous studies. Unit costs were based on market prices (drugs) and customary charges in Sweden. All costs were expressed in Swedish kronor (SEK), year 2004 values euro 1.00 approximately SEK9.17, $US1.00 = SEK7.47). Future costs and outcomes were discounted at 3%. One-way and probabilistic sensitivity analyses were conducted. The mean utility scores were 0.77 for DLI and 0.72 for conventional therapy (p = 0.02). A considerable variation in the scores was observed during the study. The expected per-patient 2-year cost of DLI was SEK562 000 while it was SEK172 000 for conventional therapy. The mean number of QALYs was 1.48 and 1.42, respectively, representing an incremental cost of SEK6.1 million per QALY for DLI (all values discounted at 3%). Using other assumptions in sensitivity analyses, the cost per QALY could be as low as SEK456 000. This analysis can be considered exploratory only; it is based on very limited data. Nevertheless, our findings suggest that DLI results in a significant improvement in HR-QOL. However, the cost per QALY is likely to be higher than customary cost-effectiveness thresholds. Whether these benefits justify the additional costs depends on how the health benefits are measured and how these benefits are valued by society.