OBJECTIVES: Emergence of long-term side effects of treating Parkinson’s disease (PD) patients with levodopa, particularly dyskinesia (levodopa induced dyskinesia - LID), limit the ability to optimally treat symptoms and consequences of PD. PD-LID interferes with performance of activities of daily living, ambulation and balance and increases health care costs. There are no approved treatments and no studies examining cost-effectiveness of an intervention for PD-LID. Objective of the present study is to develop a de-novo economic model to identify the value drivers for a drug to be cost-effective for treatment of PD-LID.
METHODS: The model combines a short-term (6 months) decision tree, to determine initial response to the drug, with a long-term Markov approach to model transition of patients across LID severity over lifetime. The model classifies LID severity using modified Abnormal Involuntary Movement scale (mAIMS) with disease states defined as mild (0-12), moderate (13-18) and severe (19-24). Disease state specific costs included costs of drug treatments, consultations/visits, paramedical services, laboratory tests, radiological examinations, hospitalizations, community/social services and unpaid services. State specific utilities were calculated and assigned based on literature.
RESULTS: The model suggests that initial response to the treatment, ability to improve and halt worsening dyskinesia health states are the greatest value drivers of the treatment for PD-LID. More than 90% of costs were driven by medical costs. A treatment for PD-LID that results in 6-month response rate of at least 50%, 25% increase in the probability of dyskinesia improving and 25% reduction in the probability of dyskinesia worsening results in a 0.28 QALY gain per patient.
CONCLUSIONS: This economic analysis suggests that a health care intervention that could improve the clinical parameters of dyskinesia can have significant beneficial impact on costs and utilities. Further studies are required to characterize the underlying disease progression parameters and strengthen these assessments.
