Costs and cost-drivers of a diagnosis of depression among adults with epilepsy in the United States

Objective: The objective of this study was to evaluate the amount of direct costs associated with occurrence of depression in people with epilepsy. Methods: The Medical Expenditure Panel Survey Household Components (MEPS-HC) served as data source to identify adults (≥ 18 years) with epilepsy from 2003 to 2014, using the Clinical Classification Code CCC-83. Annual unadjusted per person total healthcare expenditures and individual cost components (inpatient, outpatient, prescription, emergency room, and home health) were compared between people with epilepsy and depression vs. without depression. A two-part model estimated the adjusted incremental direct cost of depression (total and individual cost components) among adults with epilepsy. The model was adjusted for sex, race/ethnicity, education, marital status, insurance status, census region, income, Charlson Comorbidities index (CCI), and year trend. Results: Out of a weighted 1,942,413 US adults with epilepsy, 675,037 (34.7%) had a diagnosis of depression. Annual total unadjusted per person direct cost of depression was $5290 higher in people with epilepsy vs. without [$18,776 (95% confidence interval [CI]: 16,241–21,311) vs. $13,486 (95%CI: 9780–17,191)]. Costs for outpatient and prescriptions were higher among people with epilepsy plus depression vs. without depression, but no differences were observed for inpatient, emergency room, and home health costs. In the adjusted model, total costs [$2523 (95%CI: 62–4984)], incremental annual direct costs per person for outpatient [$1940 (95%CI: 1266–2613)], prescriptions [$1285 (95%CI: 772–1798)], and emergency room [$191 (95%CI: 20–361)] were significantly higher for people with epilepsy plus depression. Unadjusted and adjusted incremental total aggregate annual direct costs of depression for people with epilepsy were $3.5 billion and $1.7 billion respectively. Conclusion: Costs of epilepsy with presence of depression in the US are high, and primarily driven by outpatient, prescriptions, and emergency room costs.