Abstracts

Rationale:
Several lines of evidence have suggested that exposure to enzyme-inducing anti-seizure medications (ASMs) may result in the subsequent development of hyperlipidemia, a well -known risk factor for vascular disease. This may be an issue of concern, particularly in the context of additional comorbid vascular risk factors. We therefore aimed to investigate trends of and associations with the use of these medications among adults with epilepsy (AWE).
Method:
The cross-sectional Medical Expenditure Panel Survey (MEPS) was interrogated to ascertain the prevalence of use of enzyme-inducing ASMs by noninstitutionalized AWE in the United States between the years 2004 and 2015. Any patient prescribed carbamazepine, phenytoin, phenobarbital, or primidone within a given year was defined as having been prescribed an enzyme-inducing ASM. Temporal trends over three-year epochs were evaluated with univariate logistic regression, while associations with demographic factors, vascular risk factors and vascular disease, were evaluated using a chi-square test corrected for survey design.
Results:
A total of 2,281 (unweighted) AWE were identified, representing 1,781,237 AWE.  Of these, 45.9% (95% CI 42.4%-49.4%) were prescribed enzyme-inducing ASMs between 2004 and 2015. We found that 25.3% (95% CI 21.1%-30.0%) of AWE aged 65 years and above used enzyme-inducing ASMs compared to 18.5% (95% CI 15.5%-22.1%) of younger patients (p=0.01) (Table 1). In addition, 46.3% (95% CI 41.5%-51.3%) of AWE prescribed enzyme-inducing ASMs were women, compared to 57.7% (95% CI 53.6%-61.6%) of AWE not prescribed enzyme-inducing ASM (p< 0.001). There was no significant difference in the use of enzyme-inducing ASMs in those with known vascular disease or other vascular risk factors. However, among those prescribed enzyme-inducing ASMs, 38.9% had hypertension, 12.2% had diabetes, 61.6% were overweight or obese, 18.6% had heart disease, 17.2% had a history of a cerebrovascular event and 28.5% had diagnosed hyperlipidemia. Nonetheless, between 2004-2006 and 2013-2015, the odds of enzyme-inducing ASM prescription decreased significantly (OR 0.39, 95% CI 0.28-0.55) (Table 2).   
Conclusion:
A substantial proportion of AWE with comorbid vascular disease or vascular risk factors (e.g. hypertension and older age) are prescribed enzyme-inducing ASMs. This could potentially increase patients’ risk for subsequent negative outcomes such as cardiovascular or cerebrovascular disease. Though utilization of these medications has decreased, further efforts towards increasing use of newer ASMs that are not associated with similar risks may be warranted.
Funding:
:None