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Purpose: To assess differences in medical care expenditures and informal care received for adults and children by individuals’ self-reported epilepsy status and to estimate the total economic impact of epilepsy in the United States.
Methods: Pooled medical expenditure panel survey data from 1996–2004 were used. Children’s regression analyses were adjusted for race, sex, general self-reported health status, family size, and age. Adults’ analyses were also adjusted for income and education. The national annual economic impact was estimated by multiplying the average individual differences by previously published national prevalence data.
Results: The results of regressions appropriately weighted to account for study design indicate excess medical expenditures for those with epilepsy of $4,523 [95% confidence interval: $3,184–$5,862]. Excess expenditures were similar for adults and children. Adults with epilepsy received 1.2 extra days of informal care [95% confidence interval: 0.2–2.3]. The national impact included $9.6 billion of medical expenditures and informal care.
Discussion: Epilepsy has significant impact on individual medical expenditure and generates a national impact in the billions of dollar.
Epilepsy imposes a burden on society by imposing a significant burden on both the individuals who have the condition and on those around them. Numerous attempts have been made to assess the burden of epilepsy on society in countries including India, Burundi, Australia, European countries (Beran, 1999a; Heaney et al., 2001; Thomas et al., 2001; Nsengiyumva et al., 2004), and the United States (Begley et al., 1994, 2000; Griffiths et al., 1999).
In the United States, Begley et al. (1994) estimated the lifetime cost for the incidence cases based on the prognostic group. They divide their study group into six prognostic groups, ranging from the permanent remission group after initial diagnosis and treatment to the institutionalized intractable seizures group, according to severity. This level of detail allowed them to present a range of results. By applying the different health care utilization probabilities determined by the expert panel and the different productivity losses derived by national survey and other studies according to those severity and prognostic groups, they concluded that the total lifetime cost per patient ranged from $4,272 for persons with remission after initial diagnosis to $138,602 for persons with severe seizures, in 1990 dollars. Griffiths et al. (1999) reported the payer cost of epilepsy by using administrative claims data for a 9,090 epilepsy patient cohort. They reported that the mean total annual cost of all medical services for those who have epilepsy was $9,617 during 1992 and 1996. Begley et al. (1994) later estimated that the total cost of epilepsy for the United States in 1995 was $12.5 billion (Begley et al., 2000). Their cost estimate consisted of $1.7 billion direct medical cost projected from 608 cases in two metropolitan areas and $10.8 billion indirect cost from productivity loss projected from 1,168 surveyed adult patients at the 18 epilepsy treatment centers.
Although various approaches are possible to illustrate the health care burden for epilepsy patients and families, no report to date has been able to take advantage of a large nationally representative survey with high quality data on self-reported utilization and medical conditions. Nine years of data from the medical expenditure panel survey (MEPS) were used for this study. This survey has been administered annually since 1996 by the Agency for Healthcare Research and Quality (AHRQ) and includes 10,000 to more than 20,000 individuals each year (Agency for Healthcare Research and Quality, 2007). This quantity of data allows researchers to estimate the excess resource utilization associated with relatively rare conditions. An analysis of these data will allow us to infer the association of epilepsy with medical care and informal care in a way that was not previously possible in the United States.
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Table 1 summarizes the characteristics of the population. A total of 264,513 had no missing data and were included in the analysis. Among these, 78,475 (29.7%) were children. The prevalence of epilepsy for the 1996–2004 MEPS was 0.9% (95% CI: 0.8–1.1%) for the children and 1.0% (95% CI: 0.9–1.1%) for the adults. Among both children and adults, in comparison to those without epilepsy, those with epilepsy were more likely to have only public insurance, less likely to be uninsured, and less likely to express good health status or better. Among adults, those with epilepsy were less likely to be married, more likely to have no more than a high school education, and more likely to have an income below the median level.
Table 1. Characteristics of the respondents of the 1996–2004 medical expenditure panel survey by epilepsy status
|Characteristics||Without epilepsy||With epilepsy||Total|
|Total study population||261,676||99.0||98.9–99.1||2,837||1.0||0.9–1.1||264,513||100.0|| |
| Total||77,705||99.1||98.9–99.2||770||0.9||0.8–1.1||78,475||100.0|| |
| Reported good, very good, or excellent health status||75,547||97.8||97.6–98.0||565||81.4||77.6–85.2||76,112||97.6||97.5–97.8|
| Any private insurance||42,949||68.0||66.7–69.4||358||55.9||50.6–61.3||43,307||67.9||66.6–69.2|
| Public insurance only||26,346||23.4||22.2–24.5||386||40.5||35.2–45.7||26,732||23.5||22.3–24.7|
| Age, years (mean)||8.7|| ||8.6–8.8||7.7|| ||7.0–8.3||8.7|| ||8.6–8.8|
| Family size (mean)||4.4|| ||4.4–4.5||4.3|| ||4.1–4.6||4.4|| ||4.4–4.5|
| Total||183,971||99.0||98.9–99.1||2,067||1.0||0.9–1.1||186,038||100.0|| |
| Education level|
| Less than high school||49,008||20.1||19.5–20.8||787||32.1||28.4–35.9||49,795||20.3||19.6–20.9|
| High school graduate||60,000||32.9||32.2–33.5||739||36.3||32.5–40.1||60,739||32.9||32.3–33.5|
| Some college||38,278||22.6||22.1–23.1||307||17.0||13.9–20.1||38,585||22.5||22.1–23.0|
| College and up||36,685||24.4||23.5–25.3||234||14.6||11.6–17.6||36,919||24.3||23.4–25.2|
| Reported good, very good, or excellent health status||157,226||87.6||87.2–88.0||1,098||56.8||53.3–60.4||158,324||87.3||86.9–87.7|
| Any private insurance||123,192||74.3||73.5–75.1||892||49.3||45.4–53.1||124,084||74.0||73.2–74.9|
| Public insurance only||29,817||12.8||12.2–13.4||953||40.7||36.9–44.5||30,770||13.1||12.5–13.7|
| Income quartile|
| $9707 –$20,839||43,821||22.4||22.0–22.9||532||25.6||23.1–28.1||44,353||22.5||22.0–23.0|
| $20,840 –$38105||43,975||25.2||24.8–25.6||299||17.0||14.5–19.4||44,274||25.1||24.7–25.5|
| $38,106 –||43,702||28.8||28.0–29.6||191||11.6||9.6–13.6||43,893||28.7||27.9–29.4|
| Age (mean)||45.1|| ||44.8–45.4||48.1|| ||46.6–49.6||45.2|| ||44.9–45.5|
| Family size (mean)||2.8|| ||2.8–2.9||2.6|| ||2.5–2.7||2.8|| ||2.8–2.9|
Table 2 shows unadjusted means and confidence intervals for expenditures and informal care days accounting for weights and study design as well as adjusted differences. Total annual medical expenditures for children with epilepsy were $6,379 (95% CI: $4,203–$8,555) and for children without epilepsy were $1,032 (95% CI: $989–$1,976). The adjusted difference was less than the unadjusted difference but remained statistically significant at $4,703 (95% CI: $2,609–$6,797). For children, the difference in days of informal care was not statistically significant. For adults, both adjusted differences were statistically significant. For expenditures, the difference was $4,465 (95% CI: $2,925–$6,005); for informal care days the difference was 1.2 (95% CI: 0.2–2.3). The average difference in expenditures when combining adults and children was $4,523 (95% CI: $3,184–$5,682).
Table 2. Mean total health care expenditure amount and informal care days and unadjusted and adjusted differences for individuals without or with epilepsy using 1996–2004 medical expenditure panel survey data
| ||Outcome measuresa||Without epilepsy||With epilepsy||Unadjusted difference||Adjusted differenceb|
|Informal care days||0.0||0.0–0.0||0.5||−0.4–1.3||0.4||−0.4–1.3||0.4||−0.4–1.2|
|Informal care days||0.4||0.4–0.5||2.5||1.5–3.6||2.1||1.0–3.1||1.2||0.2–2.3|
|Informal care days||0.3||0.3–0.4||2.0||1.2–2.9||1.7||0.9–2.5||1.2||0.3–2.1|
After adjusting for potential confounders, the odds ratio of any positive expenditure for children with epilepsy compared to children without out epilepsy was 7.9 (95% CI: 4.3–14.5). The same odds ratio of any positive expenditure for adults was 11.4 (95% CI: 7.1–18.5). The excessive medical expenditure is significantly higher for those with epilepsy when we analyzed the individuals only with positive expenditure. Among those who have positive expenditure, the excessive expenditure of the children with epilepsy compared to the children without epilepsy was $4,642 (95% CI: 2,516–6,767) and the excessive expenditure for adults with epilepsy was $4,193 (95% CI: 2,638–5,749). The two-part model suggests that among those who used any health care, the individuals with epilepsy had considerably higher expenditures than those without epilepsy. Therefore, those with epilepsy are both more likely to use any care, and among those who have used any care, those with epilepsy have a higher average expenditure.
Table 3 shows the total aggregated annual economic impact of epilepsy and its calculation process. With the assumption of 2.1 million epilepsy prevalence, the estimated medical expenditure was $9.5 billion dollars. With the additional assumption of $41.2 a day minimum wages, the estimated value of informal care was $99.6 million dollars. The total aggregated annual economic impact of epilepsy on the U.S. economy includes $9.6 billion dollars from medical expenditures and informal care.
Table 3. Total economic impact of epilepsy in the United States
|Estimates||Estimated value||95% CI|
|Individual annual excess medical expenditure, mean $||4,523||3,184–5,862|
|Estimated number of people with epilepsya||2,098,000||Not available|
|Excess medical expenditure, mean $||9,488,530,190||(6,679,136,154–12,297,924,226)|
|Individual excess informal care days, mean||1.15||0.25–2.05|
|Minimum wage per day b, $||41.2||Not available|
|Value of informal care days, $||99,576,288||(21,618,165–177,534,446)|
|Total annual monetary impact, $||9,588,106,478||(6,700,754,319–12,475,458,672)|
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We demonstrated that the average individual health care cost of epilepsy is substantial, even after adjusting for various individual characteristics. The average excessive health care expenditure of $4,523 due to epilepsy is substantially larger than previously estimated. Begley et al. (2000) estimated the average direct cost for epilepsy prevalent cases at year 1995 was $733 or $909 when adjusted for inflation to a 2004 value (Begley et al., 2000). Although Begley et al. (2000) focused on incident cases that are likely to cost more (Begley et al., 2000; White, 2007), our results were of greater magnitude. This is because the prior article looked at costs only specifically related to epilepsy as judged by patients and physicians rather than all medical care expenditure differences, as well as the fact that the overall cost of care has increased (Heaney et al., 2002; Centers for Medicare and Medicaid Services, 2008). On the other hand, our estimation for total health care expenditure for people with epilepsy of $9,181 is less than that calculated by Griffiths et al. (1999) using insurance claim data. Based on private insurance claims data, they estimated that the mean annual cost of all medical services for patients with epilepsy was $9,617 between 1992 and 1996, which is $11,578 in 2004 dollar value. The difference in insurance types, that is, private insurance population versus general population, and study data, that is, claims data versus survey data, would be the reason for this difference.
The economic burden of the disorder (or the cost of all prevalent cases of epilepsy) includes nearly $9.5 billion of direct medical care costs and additional informal care costs that lead to an overall monetary burden of almost $9.6 billion. There is an ongoing discussion in the literature about the scope of the cost of illness (Annegers et al., 1999; Beran, 1999b; Pachlatko, 1999; Kotsopoulos et al., 2001). This analysis is somewhat limited because it does not factor quality of life into the cost of illness, does not consider the cost of an incident case over time, and does not include the productivity loss cost. However, this is the first study that has taken a largely bottom-up approach to calculating the costs of epilepsy using such a large dataset. The bottom-up approach used an estimate of excess expenditures at the individual level and multiplies it by the number of cases to estimate the impact at the national level. It would be difficult to ever use a top-down approach for this calculation, as it would require national data on expenditures and some indication of the prevalence of epilepsy (Begley & Beghi, 2002).
In our study, adults with epilepsy received significantly more informal care than adults/people without epilepsy. The lack of a statistically significant finding for children is probably not due to the fact that children do not need assistance but that children are likely to receive assistance from individuals within their households. The dollar value of the burden associated with informal care may have been higher than we estimated, as we assumed a minimum wage for all informal care providers.
Our study results showed that having epilepsy is associated with higher expenditures, both because of being more likely to make any expenditures and because those who make expenditures make higher expenditures on average. One thing that could help to account for the higher probability of any utilization is the fact that a previous U.S. national survey indicated that 90% of epilepsy patients were taking one or more antiepileptic medications (Fisher et al., 2000). The higher expenditures among those with epilepsy occur despite steps that insurers take to control expenditures such as cost-containing strategies including “prior authorization” for high cost drugs, a step approach, and generic drug promotion (Theodore et al., 2006; Bialer, 2007).
There are several limitations in our study. First, the estimate of the economic impact is limited because we were not able to include productivity loss and intangible costs. Productivity loss and intangible costs such as cost associated with stigma were known to constitute a significant portion of the cost of epilepsy (Beran, 1999b). Second, we inferred the epilepsy status by ICD-9 based on the medical care utilization. The epilepsy status might be not accurate because the diagnosis of epilepsy was not confirmed. Holden et al. (2005) reported the discrepancy between ICD-9 and a true epilepsy diagnosis. This likely biases the results toward the cost of more active cases, which are of greater interest at the individual level, but might lead to overestimates of the burden at the population level. Third, inferring an average cost-effect from 9 years of data is a limitation in the study, given the changes in treatment during that time (Perucca et al., 2007; Baaj et al., 2008). However, given the relatively small number of cases, making an inference from fewer years would lead to other analytic difficulties. Fourth, epilepsy is known to be associated with learning disability, emotional problems, mental retardation, and brain injury (Begley et al., 1999). The additional costs of these conditions in the educational and other nonmedical care systems are not included in our estimates.
Despite these limitations, we have demonstrated that epilepsy has a significant impact on the national economy as well as individuals. Our estimation can be used to determine the individual and societal burden of epilepsy.