Health care cost associated with the use of enzyme-inducing and non-enzyme–active antiepileptic drugs in the UK: a long-term retrospective matched cohort study

Abstract

BackgroundSome antiepileptic drugs (AEDs) induce expression of hepatic enzymes. This can contribute to comorbidities via interference with metabolic pathways and concomitant drug metabolization, thereby increasing the likelihood of health care interventions. Using medical records, we compared the direct health care cost in patients initiating epilepsy therapy with enzyme-inducing AEDs (EIAEDs) vs non-enzyme-active AEDs (nEAAEDs) over up to 12 years.MethodsPatients with untreated epilepsy were indexed in the UK Clinical Practice Research Datalink and Hospital Episode Statistics database when prescribed a new EIAED or nEAAED between January 2001 and December 2010. Propensity score matching reduced confounding factors between cohorts. Patients were followed until cohort treatment failure or data cut-off. The primary outcome was the median standardized monthly direct health care cost during follow-up in 2014 £GBP, calculated using published reference costs and compared using a Mann–Whitney U test.ResultsThe unmatched EIAED cohort (n = 2752) was older (54 vs 46 years), more likely to be male, had more comorbidities, and higher health care resource use/cost during the 1-year pre-index period (median £3014 vs £2516) than the nEAAED cohort (n = 2,137). The most common index EIAED and nEAAED were carbamazepine (63.3%) and lamotrigine (58.0%), respectively. After matching, cohorts had similar features (n = 951 each). Over up to 12 years of follow-up, the median standardized monthly direct health care cost was £229 for the EIAED and £188 for the nEAAED cohorts (p = 0.0091). The median cost was higher for the EIAED cohort in every year of follow-up. In the two cohorts, 25.1% and 20.1% of total mean cost during follow-up was epilepsy-related, with approximately 4.6% and 3.0% for AED acquisition, respectively. The median time to cohort treatment failure was shorter in the matched EIAED cohort (468 vs 1194 days).ConclusionsPatients in the UK who initiated epilepsy therapy with an EIAED appeared to be at higher risk of complications associated with enzyme induction. In long-term matched cohort analyses, the median total direct health care cost associated with EIAED therapy was higher than with nEAAEDs. Changing current treatment practices could potentially improve patient outcomes and reduce costs.Electronic supplementary materialThe online version of this article (doi:10.1186/s12883-017-0837-y) contains supplementary material, which is available to authorized users.

High health care costs in minority groups of older US Medicare beneficiaries with epilepsy

“…Other quality of epilepsy care indicators we considered were not associated with high costs. There was only a tenuous association indicating lower odds of high costs for beneficiaries with QUIET 9 concordant care, in line with a study in a younger UK population in which use of enzyme‐inducing drugs was associated with higher costs than use of non–enzyme‐inducing AEDs …”

“…There was only a tenuous association indicating lower odds of high costs for beneficiaries with QUIET 9 concordant care, in line with a study in a younger UK population in which use of enzyme-inducing drugs was associated with higher costs than use of non-enzyme-inducing AEDs. 33 Factors included in our analysis were not enough to explain the higher odds of high costs for African Americans with epilepsy, except potentially for AED adherence. Because race/ethnicity differences were not observed in the random sample of Medicare beneficiaries, closer scrutiny of the health care utilization of African Americans and other demographic groups with epilepsy is warranted.…”

Comparing healthcare cost associated with the use of enzyme-inducing and non-enzyme active antiepileptic drugs in elderly patients with epilepsy in the UK: a long-term retrospective, matched cohort study

“…After up to 12 years of follow-up, the median monthly direct healthcare costs (in British Pound Sterling [£]) were higher for patients taking EIAEDs versus those taking nEAAEDs (£229 vs. £188, respectively). The time to treatment failure was shorter for the EIAED cohort versus the nEAAED cohort (468 days vs. 1194 days, respectively) [13].…”

“…This was a retrospective matched cohort study comparing the long-term healthcare costs associated with the use of EIAEDs and nEAAEDs in patients ≥65 years of age with epilepsy in the UK. The methods for this analysis were similar to those applied to the full study patients with epilepsy ≥16 years of age [13]. For this analysis, patient selection was repeated based on age (≥65 years) and cohorts were newly matched.…”

“…Our previous retrospective database analysis in adult patients with epilepsy in the UK demonstrated higher long-term healthcare costs with the use of EIAEDs compared with nEAAEDs [13]. After up to 12 years of follow-up, the median monthly direct healthcare costs (in British Pound Sterling [£]) were higher for patients taking EIAEDs versus those taking nEAAEDs (£229 vs. £188, respectively).…”