Abstracts

Rationale: Patients with refractory epilepsy and without a detectable structural abnormality on high resolution magnetic resonance imaging (non-specific MRI) are frequently referred for a comprehensive presurgical evaluation. This evaluation is intended to detect epileptogenic foci for surgical resection by detailed electroencephalograms and possibly invasive electrocorticography. Surgical outcomes can be unsatisfactory in as many as 17% of epilepsy patients, and patients with pathogenic DNA variants in certain epilepsy-causing genes generally do not benefit from surgical resection. We performed a cost-effectiveness analysis to investigate whether genetic testing for these pathogenic variants by next-generation-sequencing (NGS) would cost effectively aid in preventing unnecessary evaluations and surgeries in patients with certain genetic forms of epilepsy.Methods: We compared the costs and utilities of two epilepsy care strategies: a usual care strategy and an NGS test strategy (Figure 1). The NGS test strategy included genetic testing and palliative care rather than presurgical evaluation for patients with positive NGS test results, that is, for patients with pathogenic variant(s) in certain epilepsy-causing genes. We assessed the costs and utilities of the two strategies from a payer perspective over 5-years horizon.Results: The NGS test strategy resulted in better outcomes at a lower cost than the usual epilepsy care strategy under the baseline assumptions. Specifically, in a hypothetical population of 10,000 patients with refractory epilepsy and non-specific MRI findings, the NGS test strategy reduced healthcare costs by $34 million and added 111 quality adjusted years (QALYs). We also assessed the cost-saving potential of the NGS strategy by varying both the frequency of positive NGS test results and the fraction of patients in the usual care strategy that would undergo surgical resection (Figure 2). The NGS test strategy could save costs when the NGS test positive fraction was as low as 3.2%, depending on the rate of surgical resection in patients assumed in the usual care strategy. When the NGS test positive fraction was 4.8% or greater, the NGS test strategy would save costs, regardless of the rate of surgical resection following invasive electrocorticography assumed in the usual care strategy.Conclusions: A health economic model demonstrated that incorporating a genetic testing prior to conducting presurgical evaluation is likely to be cost saving in patients with refractory epilepsy and non-specific MRI.