Medical and employment-related costs of epilepsy in the USA

Abstract

Evaluation of: Ivanova JI, Birnbaum HG, Kidolezi Y et al. Economic burden of epilepsy among the privately insured in the US. Pharmacoeconomics 28(8), 675–685 (2010).

Epilepsy is a chronic condition characterized by recurrent unprovoked seizures. Epilepsy is typically treated with antiepileptic drugs, although surgery is superior to medical therapy for those who are resistant to medications, and is more more cost effective when successful. The discussion article examines the direct medical costs of epilepsy and the rate of medically related absenteeism compared with a matched control group in the USA. Individuals with epilepsy were found to have significantly higher medical costs and more short- and long-term disability days. This article demonstrates that claims data can be used to assess the indirect impact of epilepsy on employment; however, the addition of other datasets is necessary to more comprehensively assess the impact of epilepsy on employment-related outcomes.

Keywords::

• cost
• economics
• epilepsy
• health resource utilization
• health services
• medical absenteeism
• seizures

As stated by Ivanova et al., epilepsy is the second most common neurological condition seen in clinical practice and is estimated to affect 50 million people worldwide [1,2]. Seizure control is usually obtained with antiepileptic drugs [3]; however, for some patients who are refractory to medications, surgery is superior and may provide seizure freedom [4].

Epilepsy places an undue economic burden on patients and society. A systematic review found that the mean annual direct medical cost associated with epilepsy ranged from 40 international US dollar purchasing power parities (PPP-US$) in a developing country with limited treatment options to PPP-US$4748 in a developed country [5]. While these figures are high, they only represent a small proportion of the total costs of epilepsy, as studies have found that between 12 and 85% of the total costs can be attributed to indirect costs, such as time off work, childcare and support services that are not covered under health insurance plans [5].

The wide variation in reported epilepsy costs is likely to be multifactorial. Both the diagnosis of epilepsy and the workup for epilepsy surgery are cost-intensive processes [6]. However, once adequate seizure control is obtained, the mean annual direct medical cost of epilepsy has been shown to decline from US$3157 (1995 US dollars) in the year of diagnosis to US$411 4 years after diagnosis [6]. Similarly, despite the initial higher costs of surgery, healthcare costs decline after successful epilepsy surgery [7]. In addition, individuals with epilepsy often suffer from other comorbid conditions, particularly psychiatric comorbidities [5]. The inclusion/exclusion of comorbid conditions in cost of illness studies may also partially explain why such wide variation in both direct and indirect costs is observed. Finally, international cost comparisons are hindered by the large treatment gap that exists between developed and developing countries, where it is estimated that approximately 90% of individuals with epilepsy are untreated or undertreated [5].

To address some of the methodological discrepancies in cost of illness studies, the International League Against Epilepsy Subcommission on the Economic Burden of Epilepsy made the following recommendations: that cost of illness studies identify patients from the community (i.e., be population based) and be conducted prospectively [8]; that there is still a need for retrospective studies, but that these types of studies should focus on the general population of individuals with epilepsy rather than focus on selected patients; and that economic analysis studies aim to be comprehensive and include both direct and indirect costs; however, only costs attributable to epilepsy should be included [8].

Methods & results

The study by Ivanova et al. retrospectively reviewed medical claims data from 1999 to 2005. The authors identified 4323 individuals with epilepsy using the International Classification of Disease Version 9 Clinical Modification (ICD-9-CM) code 345.x, aged 16–64 years old, who maintained continuous health coverage during 2004–2005. Those with epilepsy were then matched on a 1:1 basis to individuals without epilepsy by age, sex, region of residence and employment status [1].

The authors calculated direct medical (inpatient care, outpatient services and emergency department visits) and pharmaceutical costs for the total sample, and indirect costs related to medical absenteeism and disability leave for the subset of employed individuals for the 2005 calendar year [1]. Direct medical costs included both epilepsy-related costs (primary or secondary diagnosis of epilepsy [ICD-9-CM 345.x] or convulsions [ICD-9-CM 780.3]) and nonepilepsy-related costs [1]. Univariable and multivariable analyses were conducted to assess for differences in direct and indirect costs for individuals with and without epilepsy [1]. Risk adjustment techniques were used to control underlying differences in patient characteristics (demographics and comorbities) [1].

Individuals with epilepsy had a significantly higher baseline prevalence of both medical and psychiatric comorbidities [1]. This association between epilepsy and comorbidities remained, even when the analysis was limited to employed individuals [1].

Not surprisingly, individuals with epilepsy had significantly higher rates of direct healthcare utilization than controls, and employees with epilepsy had significantly more disability days and claims for short- and long-term disability than controls [1]. The mean unadjusted annual direct costs per person with epilepsy were US$10,258 (2005 US dollars) versus US$3862 per control (p < 0.001) [1]. A total of 80% (US$8201) of the direct medical costs for individuals with epilepsy were not directly related to the treatment of epilepsy [1]. The mean unadjusted annual indirect costs for employees with epilepsy were US$3192 and $1242 for controls (p < 0.001) [1]. Following risk adjustment, the mean direct (US$10,016 vs 4733; p < 0.001) and indirect (US$2793 vs 1578; p < 0.001) costs remained significantly higher for individuals with epilepsy [1].

Discussion

While updating the direct medical costs of epilepsy, literature of interest to those in the field has demonstrated that these findings are not particularly surprising. Epilepsy remains a costly disorder to manage. The key novel finding of the study by Ivanova et al. relates to its assessment of the impact of epilepsy on medically related absenteeism [1].

While it has been well documented that individuals with epilepsy are more likely to be unemployed or underemployed than their peers [9], little information exists in the literature on the impact of both short- and long-term disability in terms of costs. While this study is an important step in examining the impact of epilepsy on employment, its assessment is limited by the dataset used. While claims data are useful to assess time off work, the authors are unable to assess other employment-related outcomes such as increased productivity to compensate for time off, decreased productivity as patients recover from seizures but remain at work, the impact of epilepsy on career trajectories and so on. Mixed methods research that combine survey or qualitative data on the employment-related impact of epilepsy, combined with claims data on time off work, is necessary to truly understand these indirect costs.

Also of note in this study, as in other studies, is the finding that individuals with epilepsy are significantly more likely to suffer from comorbidities than people without epilepsy, particularly psychiatric comorbidities [10–12]. It is unknown what proportion of medical absenteeism in this sample is related to epilepsy versus comorbid conditions. A subanalysis of individuals with epilepsy, stratified by comorbidity status, would be informative to attempt to explore this question.

Expert commentary & five-year view

Epilepsy has the unfortunate distinction of being both a common and a costly neurological disorder. Yet the impact of epilepsy extends beyond the direct medical costs associated with treating this disorder. Epilepsy has a significant burden on an individual’s quality of life, and can impact on the ability to find and maintain employment, drive a car, establish and maintain successful relationships, and live independently. Earlier seizure control has been shown to be improve quality of life in multiple domains, yet early treatment is often hindered by the high initial cost of treating this disease and the unequal distribution of resources [6,13].

The association between epilepsy and comorbidities, particularly psychiatric comorbidities, needs to be given greater attention, both in terms of research and clinical practice. The temporal relationship between epilepsy onset and the development of comorbid conditions needs to be assessed through prospective studies in order to triage patients into more appropriate streams of care, and ultimately, to halt the development of these co-existing conditions. A prior study found that having comorbid depression is positively associated with health resource utilization in those with epilepsy [14]. Control of comorbid conditions could result in substantial cost savings – as the study by Ivanova et al. demonstrated, 80% of the direct medical costs in epilepsy patients were not attributable to epilepsy.

While methods for estimating the direct medical cost of disease are well established, methods for estimating the indirect cost of disease require further development and standardization. Lack of consistency of included items in economic analyses prohibits comparisons across studies. The study by Ivanova et al. elegantly demonstrates the value of claims data in assessing the indirect costs of epilepsy as it relates to employment; however, this type of data alone is not sufficient to capture all of the indirect costs of this condition. Mixed methods and data linkage studies need to be explored.

In conclusion, while the direct costs of epilepsy are well established, more research is needed to better understand the indirect costs of this disease and the impact it has on the lives of individual patients. More research is also needed to better understand the natural history of this condition, and to identify potential intervention points where the course of this disease can be changed, with the ultimate goal of not only improving quality of life but also reducing epilepsy-related costs for patients, their caregivers and society.

Key issues

• • Epilepsy is a high-cost disorder that impacts the healthcare system, the insurer, employers and the individual.

• • Direct medical costs only comprise a small proportion of the total costs of epilepsy.

• • Medically related absenteeism is significantly higher for individuals with epilepsy than for controls, although the impact of this on productivity is unknown.

• • More comprehensive assessments of indirect costs that go beyond what can be assessed in a claims database are required to truly understand the total cost associated with epilepsy.

Financial and competing interests disclosure

Nathalie Jette holds salary awards from the Canadian Institutes of Health Research (CIHR; Ottawa, Canada) and Alberta Innovates Health Solutions (AI-HS; Alberta, Canada). Amy Metcalfe holds a CIHR doctoral award in Genetics (Ethics, Law and Society) and a CIHR studentship in Genes, Development and Child Health. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.