Abstracts

Rationale: Vagus Nerve Stimulation system is a fully implantable electrical stimulator, which stimulates the left vagus nerve to reduce or mitigate epileptic seizures among drug-resistant patients. 3 years have passed since VNS was approved in Japan, and clinical experience has been presented in several medical meetings. However, cost benefit reports have been limited in Europe and USA. Therefore we tried to confirm cost benefit in Japan. Methods: Seirei Hamamatsu General Hospital has experienced 78 implantations from July 2010 to November 2013. The current treatment outcome is as follows: 8% seizure free, 35% seizure reduction (defined as seizure reduction of 50% or more), 36% moderate seizure reduction (defined as seizure reduction of up to 50%), and 21% no seizure reduction. The inclusion criterion was that patients have been followed for more than 2 years in each pre VNS period and post VNS period with prescription of antiepileptic drugs. 17 patients with mean age of 28.6 years (range: 16 to 56) met the criteria of patients selection. The medical costs were surveyed due to medical prescription retrospectively. Results: Total direct medical cost in Pre VNS for 2 years was 21,519,870 JPY and Post VNS for 2 years was 11,597,610 JPY excluding drug cost. The cost reduction per patient per year was 291,831 JPY. The mean expense of the implanting system and operation fee per patient was 2,315,836 JPY, so that this cost would be absorbed in 7.9 years. On the contrary, the National Insurance System was revised to approve follow up fee for VNS in 2012. This additional cost clearly pushed up the total cost. However, cost reduction of medical examination and hospitalization absorbed it completely. The newer 4 antiepileptic drugs were approved after 2006 with extremely high prices. The price of Carbamazepine for complex partial seizure is 6.4 to 9.2 JPY per tablet of 100mg and 7.3 to 12.5 JPY per tablet of 200 mg. On the other hand, Levetiracetam is 141.4 JPY per tablet of 250mg, 230.8 JPY per tablet of 500mg. Moreover, they are not approved to utilize monotherapy and must be taken with the conventional drugs. Conclusions: VNS is a palliative therapy method for refractory epilepsy patients only recently introduced for general use in Japan. Additionally this study suggests that VNS may contribute to reduction of direct medical cost. However, we cannot analyze the cost of antiepileptic drugs because of their approval conditions. Therefore we need to study again for discussing the cost reduction of the antiepileptic drugs.