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Epilepsy or seizure disorder? The effect of cultural and socioeconomic factors on self-reported prevalence
Epilepsy & Behavior 62 (2016) 214–217
Contents lists available at ScienceDirect
Epilepsy & Behavior journal homepage: www.elsevier.com/locate/yebeh
Brief Communication
Epilepsy or seizure disorder? The effect of cultural and socioeconomic factors on self-reported prevalence Barbara L. Kroner a,⁎, Mansour Fahimi b, William D. Gaillard c, Anne Kenyon d, David J. Thurman e,1 a
RTI International, Biostatistics and Epidemiology Division, 6110 Executive Boulevard, Rockville, MD 20852, USA GfK Custom Research, LLC Marketing & Data Sciences, Wayne, PA, USA Children's National Health Systems, Division of Epilepsy and Neurophysiology, 111 Michigan Avenue NW, Washington, DC 20010, USA d RTI International, Survey Research Division, 3040 Cornwallis Road, Research Triangle Park, NC 27709, USA e Center for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, 1600 Clifton Road, Atlanta, GA 30329, USA b c
a r t i c l e
i n f o
Article history: Received 4 June 2016 Revised 5 July 2016 Accepted 6 July 2016 Available online xxxx Keywords: Seizure disorder Prevalence Race Self-report Cultural bias Stigma
a b s t r a c t Self-reported epilepsy may be influenced by culture, knowledge, and beliefs. We screened 6420 residents of the District of Columbia (DC) for epilepsy to investigate whether socio-demographics were associated with whether they reported their diagnosis as epilepsy or as seizure disorder. Lifetime and active prevalence rates were 0.54% and 0.21%, respectively for ‘epilepsy’ and 1.30% and 0.70%, respectively for ‘seizure disorder’. Seizure disorder was reported significantly more often than epilepsy among blacks, females, respondents ≥ 50 years, those with lower level education, respondents who lived alone and in low income neighborhoods, and those who resided in DC for at least five years. Clinicians should assure that patients and caregivers understand that epilepsy is synonymous with seizure disorder and other culturally appropriate terms, in order to optimize compliance with treatment, disease management instructions, and utilization of other resources targeted at persons with epilepsy. Furthermore, education and awareness campaigns aimed at improving access-to-care, reducing stigma, and increasing awareness of adverse events, such as SUDEP, should include a more diverse definition of epilepsy in their messages. © 2016 Elsevier Inc. All rights reserved.
1. Introduction For many individuals, the term ‘epilepsy’ is a complex and frightening diagnosis that is associated with social stigma. Some persons identify themselves as having a ‘seizure disorder’ rather than ‘epilepsy,’ although neurologists generally recognize these terms as equivalent in meaning. A diagnosis using either term can have far-reaching implications, particularly when it comes to self-identifying with the condition in some circumstances or populations, such as those in lower income brackets or with uncontrolled seizures [1,2]. Cultural dynamics may also play a role in self-reporting, either directly or indirectly, particularly in racially and economically diverse populations. For instance, Sirven et al. [3] found that 21% of Spanish-speaking adults in the US had no familiarity with the term epilepsy, and over 77% referred to seizures as convulsions or attacks. ⁎ Corresponding author at: RTI International, 6110 Executive Boulevard, Rockville, MD 20852, USA. E-mail addresses: [email protected] (B.L. Kroner), [email protected] (M. Fahimi), [email protected] (W.D. Gaillard), [email protected] (A. Kenyon), [email protected] (D.J. Thurman). 1 Present address: Emory University, School of Medicine, 540 Asbury Circle, Atlanta, GA 30322, USA.
http://dx.doi.org/10.1016/j.yebeh.2016.07.013 1525-5050/© 2016 Elsevier Inc. All rights reserved.
The lifetime prevalence of self-reported epilepsy in communitydwelling adults in the US has ranged from 1.2% to 2.9% [4–7]. The differences across studies may be influenced by survey mode effects (e.g., mailed surveys versus random digit dial telephone surveys) as well as differences in culture and knowledge and beliefs about epilepsy that affect the sensitivity and specificity of self-reporting. For example, false negative cases due to recall bias, untruthful responses because of stigma, or a misinterpretation or misunderstanding of the question being asked will generally go uncounted and result in underestimation of the prevalence. Conversely, false positive cases, such as those that have experienced only provoked, febrile, or psychogenic nonepileptic seizures artificially increase the prevalence estimates. The latter can often be resolved through record-based validation studies; however, population-based studies do not always include this component. In reports of validation of self-reported epilepsy, population-based studies based on self-reports do indeed provide prevalence rates that are higher than clinical record-based studies with few exceptions [8–10]. In the Behavioral Risk Factor Surveillance Surveys (BRFSS) conducted in 19 States, a nonstatistically significant higher prevalence of epilepsy was found in Blacks compared with Whites [6]. Although also not statistically significant, a higher prevalence of self-reported epilepsy among Blacks compared with Whites was found in a biracial area of
B.L. Kroner et al. / Epilepsy & Behavior 62 (2016) 214–217
Mississippi when a more extensive set of survey questions was used [11] and in a multiracial community in New York City [12]. We conducted a population-based survey in the District of Columbia (DC), one of the most culturally, racially, and economically diverse populations in the nation, to estimate the prevalence and incidence of epilepsy in various demographic categories, as defined by either the clinical term epilepsy or the more generic term seizure disorder. Using the combined definition, we found that the epilepsy prevalence in non-Hispanic blacks was twice that found in non-Hispanic whites, after adjusting for age and education [13]. Here we report on the prevalence and incidence of epilepsy and seizure disorder, separately, within the adults that completed the screening survey, to demonstrate that subpopulations of affected persons are more likely to identify their condition as seizure disorder as opposed to epilepsy.
215
reported a total of 581,847 residents for the entire DC [14]. The 2009 census data coincided with the time of sample selection and are consistent with those used in the previous report. Findings presented for highest education level completed, which include graduate school, were restricted to the 6128 primary respondents at least 25 years of age. This is consistent with the age restriction used by the U.S. Census for reporting results on educational attainment. In a second phase of the study, cases were mailed another survey which asked about employment, quality of life, comorbidities, seizure type, severity, frequency, and duration, treatment, and whether the case had ever had seizures as a result of a fever, head injury, drug or alcohol use, a stroke, or an acquired medical condition. This survey was used to categorize the etiology of the seizures and the confirmation of epilepsy by the study team neurologist (WDG) [13].
2. Material and methods 3. Results The full description of the study methods are described elsewhere [13]. Briefly, we used the Computerized Delivery Sequence File (CDSF) of the US Postal Service, the most complete address database available in the US providing near perfect coverage, as the sampling frame to select a representative sample of 20,000 household addresses in DC. In order to increase the number of respondents in the analytical subgroups of interest, including Black and non-Black residents in the highest and lowest income strata, households in certain Census Block Groups were over-sampled according to the allocation summarized in Table 1. A single page bi-lingual epilepsy screening questionnaire was then mailed to the probability-based sample of 20,000 households in DC. The survey and the corresponding letter of invitation, which included a statement of informed consent, were approved by the institutional review board for protection of human subjects at RTI International. Nonrespondents to the first wave were mailed a second survey or called on the telephone by a trained interviewer. The survey instructions called for a complete enumeration of all household members, including their demographic characteristics. The instructions also stated that the person completing the survey should be listed on the form as the first member of the household, and hereafter we refer to this person as the primary respondent. For this report, we included only the information corresponding to the primary respondent, realizing that the proxy information on the other household members provided by the primary respondent would be influenced by their attitude and knowledge regarding the terms epilepsy and seizure disorder. The first epilepsy screening question on the survey was derived from the Behavioral Risk Factor Surveillance System's (BRFSS) epilepsy module [6] and asked “Ever diagnosed with epilepsy or a seizure disorder?” with response options: No, Yes epilepsy, and Yes seizure disorder. Three response options were included to maximize the chance of identifying all possible cases of epilepsy in a single question in our culturally diverse population. Active epilepsy or seizure disorder was defined as a positive response to the second screening question “Currently taking any medicine to control seizures?”. All response data were weighted to reflect the sampling design and compensate for differential nonresponse and coverage. The population totals included in the weighting procedures were obtained from the 2009 Current Population Survey, which
There were 6447 primary respondents (6420 adults) that returned the screening survey for an overall adjusted response rate of 36.6%. The demographic composition of the adult primary respondents is presented in Table 2. There were more females (60.5%) than males (39.5%) and slightly more Blacks (45.2%) than Whites (44.4%). Half of the adult study population was at least 50 years of age and 39.7% had attended at least some graduate school. Primary respondents accounted for 107 (61.5%) of the 208 total cases of epilepsy or seizure disorder reported in 201 households. Weighted estimates and 95% confidence intervals for individual lifetime prevalence in the adult primary respondents were 0.54% (0.34–0.74) for epilepsy and 1.30% (0.98–1.62) for seizure disorder for an overall lifetime prevalence of 1.84% (1.47–2.21) for either condition. Adult primary respondents with active epilepsy were also significantly more likely to identify their condition as a seizure disorder than as epilepsy—0.70% (0.47–0.94) versus 0.21% (0.08–0.33). Of the 6420 primary respondents that were at least 18 years of age, the demographic characteristics by history of each self-reported condition are presented in Table 2. Lifetime prevalence of seizure disorder was reported more often than epilepsy in all primary respondent subgroups except those age 18–30 years. The comparative rates for seizure disorder ranged from almost equal compared with epilepsy to three times higher than that reported for epilepsy. The prevalence of seizure disorder was significantly higher than epilepsy among non-Hispanic Blacks, females, those 50 years of age or older, those with only a high school education, those living in low income neighborhoods, and those who resided in DC for at least five years. Prevalence results for active seizure disorder and active epilepsy by demographic subgroups are presented in Table 3, and in all subgroups the rates were higher for self-reported seizure disorder than they were for self-reported epilepsy. The prevalence of active seizure disorder was significantly higher than the prevalence of active epilepsy among the same six subgroups identified for lifetime prevalence and included non-Hispanic Blacks, females, those 50 years of age or older, those with only a high school education, those living in low income neighborhoods, and those who resided in DC for at least five years. In four subgroups (young adults, Hispanic, race other than White or
Table 1 Distribution of all households in DC and in the sample by percent Blacks and median household income from Census. Percent Blacks in CBG
N95% 70–94% 10–69% b10% Total
Median household income for census block group Less than $30,000
$30,000–$39,999
$40,000–$49,999
More than $49,999
Total
DC
Sample
DC
Sample
DC
Sample
DC
Sample
DC
Sample
15.2% 8.8% 4.5% 0.5% 29.0%
18.0% 5.2% 2.6% 3.7% 29.5%
6.9% 7.7% 6.3% 1.6% 22.5%
8.1% 4.5% 3.7% 1.9% 18.2%
1.2% 4.4% 3.8% 3.8% 13.2%
1.4% 2.6% 2.3% 4.5% 10.8%
1.2% 3.9% 8.8% 21.4% 35.3%
8.7% 2.3% 5.2% 25.3% 41.5%
24.5% 24.8% 23.4% 27.3% 100.0%
36.2% 14.6% 13.8% 35.4% 100.0%
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B.L. Kroner et al. / Epilepsy & Behavior 62 (2016) 214–217
Table 2 Demographics of primary respondents with a history of self-identified epilepsy and selfidentified seizure disorder. Sample sizea
% history of epilepsy or seizure disorder (95% CI)
% history of epilepsy only (95% CI)
% history of seizure disorder only (95% CI)
6420
1.84 (1.47–2.21)
0.54 (0.34–0.74)
1.30 (0.98–1.61)
Gender Male Female
2539 3881
1.92 (1.31–2.53) 1.79 (1.32–2.25)
0.67 (0.32–1.04) 0.45 (0.22–0.67)
1.24 (0.75–1.74) 1.34 (0.93–1.75)
Age 18–30 years 30–49 years ≥50 years
947 2265 3208
0.88 (0.27–1.50) 1.80 (1.20–2.41) 2.19 (1.60–2.79)
0.46 (0.02–0.91) 0.55 (0.23–0.87) 0.56 (0.26–0.87)
0.42 (0–0.85) 1.26 (0.74–1.78) 1.63 (1.12–2.14)
2851
1.12 (0.73–1.52)
0.48 (0.22–0.75)
0.64 (0.34–0.94)
2903
2.53 (1.89–3.18)
0.64 (0.32–0.97)
1.89 (1.33–2.45)
309 357
0.96 (0–1.95) 1.47 (0.02–2.93)
0.26 (0–0.77) 0.29 (0–0.86)
0.71 (0–1.56) 1.18 (0–2.52)
4.69 (2.21–7.17)
1.19 (0–2.57)
3.50 (1.41–5.60)
2.63 (1.48–3.79)
0.31 (0–0.68)
2.33 (1.23–3.42)
2.04 (1.39–2.68) 0.78 (0.43–1.13)
0.86 (0.46–1.27) 0.17 (0.01–0.32)
1.17 (0.67–1.68) 0.61 (0.29–0.93)
Census block income b$30K 1554 $30K–$49K 2026 $50K or more 2840
3.08 (2.16–4.01) 1.13 (0.64–1.62) 1.45 (0.97–1.92)
0.74 (0.28–1.21) 0.24 (0.02–0.46) 0.68 (0.35–1.01)
2.34 (1.53–3.14) 0.89 (0.45–1.32) 0.77 (0.43–1.10)
Years lived in DC b5 1387 5 or more 5033
0.83 (0.31–1.34) 2.11 (1.66–2.56)
0.38 (0–0.75) 0.59 (0.35–0.82)
0.45 (0.10–0.80) 1.52 (1.13–1.91)
All primary respondents
Race/ethnicity White, non-Hispanic Black, non-Hispanic Hispanic Other
Highest educationb Less than high 327 school High school 860 graduate College 2393 Graduate 2548 school
Table 3 Demographics of primary respondents currently taking medication to control seizures and with a history of self-identified epilepsy and self-identified seizure disorder. Sample sizea
% active epilepsy or seizure disorder (95% CI)
% active epilepsy only (95% CI)
% active seizure disorder only (95% CI)
6420
0.91 (0.64–1.18)
0.21 (0.08–0.33)
0.70 (0.47–0.94)
Gender Male Female
2539 3881
0.95 (0.52–1.38) 0.88 (0.54–1.23)
0.38 (0.10–0.66) 0.08 (0–0.17)
0.57 (0.24–0.90) 0.80 (0.47–1.13)
Age 18–30 years 30–49 years ≥50 years
947 2265 3208
0.16 (0–0.46) 0.81 (0.38–1.25) 1.25 (0.80–1.69)
0 0.16 (0–0.36) 0.31 (0.10–0.53)
0.16 (0–0.46) 0.65 (0.26–1.04) 0.93 (0.54–1.32)
2851
0.43 (0.18–0.69)
0.18 (0.02–0.35)
0.25 (0.06–0.44)
2903
1.33 (0.86–1.80)
0.27 (0.06–0.48)
1.06 (0.64–1.49)
309 357
0.58 (0–1.40) 0.75 (0–1.79)
0 0
0.58 (0–1.40) 0.75 (0–1.79)
3.01 (0.94–5.07)
1.16 (0–2.51)
1.85 (0.26–3.43)
1.47 (0.62–2.32)
0.19 (0–0.53)
1.28 (0.55–2.14)
0.84 (0.43–1.25) 0.39 (0.13–0.65)
0.30 (0.05–0.46) 0.07 (0–0.16)
0.54 (0.21–0.82) 0.32 (0.08–0.56)
Census block income b$30K 1554 $30K–$49K 2026 $50K or more 2840
1.66 (0.95–2.36) 0.51 (0.19–0.84) 0.64 (0.32–0.95)
0.24 (0–0.53) 0.14 (0–0.30) 0.25 (0.04–0.45)
1.41 (0.77–2.06) 0.38 (0.10–0.66) 0.39 (0.15–0.63)
Years lived in DC b5 1387 5 or more 5033
0.10 (0–0.30) 1.12 (0.79–1.46)
0 0.26 (0.10–0.42)
0.11 (0–0.30) 0.86 (0.57–1.16)
All primary respondents
Race/ethnicity White, non-Hispanic Black, non-Hispanic Hispanic Other
Highest educationb Less than high 327 school High school 860 graduate College 2393 Graduate 2548 school
Bold means the percentage of people reporting a history of seizure disorder is significantly higher than the percentage of people reporting a history of epilepsy. a Number of unweighted observations. b Among those at least 25 years of age.
Bold means the percentage of people reporting active seizure disorder is significantly higher than the percentage of people reporting active epilepsy. a Number of unweighted observations. b Among those at least 25 years of age.
Black, and those residing in DC for less than 5 years), all of the affected primary respondents identified their condition as seizure disorder. Additional surveys about epilepsy and seizure history were completed by 70 (65.4%) of the 107 primary respondent cases, of which 22 (31.4%) identified their condition as epilepsy and 48 (68.6%) identified their condition as seizure disorder. Symptomatic causes for the seizures that we specified in the survey were found in 35 (50%) and were significantly more prevalent in those with self-reported seizure disorder compared with those with self-reported epilepsy [29 (60.4%) versus 6 (27.3%), p = .02]. Specific causes in the seizure disorder and epilepsy groups, respectively, were trauma only (18.8% versus 13.6%), stroke only (6.3% versus 4.5%), drugs or alcohol only (10.4% versus 0%), trauma plus stroke, alcohol or drug use (12.5% versus 4.5%) and chronic medical condition such as multiple sclerosis, hypertension, congenital arteriovenous malformation, migraines, and brain tumor (12.5% versus 4.5%). In the overall group of 19 adult cases with seizures due to trauma, three had gunshot wounds to the head. Small numbers limited the ability to calculate weighted prevalence rates for the symptomatic cases stratified by demographic characteristics.
surveillance screening question, identified their condition as a seizure disorder rather than epilepsy when provided with the two options. Primary respondents were also more likely to identify their condition as a seizure disorder than as epilepsy in each of the demographic subgroups, and significantly more seizure disorder than epilepsy was reported in several subgroups related to lower socioeconomic status, for both prevalent and active disease. The consistently higher self-identification with seizure disorder over epilepsy across all subgroups, including the highly educated, suggests that those with seizure disorder are unlikely to be false positive cases of epilepsy. We demonstrated that there was significantly more symptomatic epilepsy in the seizure disorder group compared with the epilepsy group which may partially explain our findings. Some people may be more inclined to think that epilepsy is the diagnosis when there is no known cause for the seizures. In particular, trauma was associated with seizures in 27% of the primary respondents with epilepsy in DC compared with less than 9% reported by others [15]. However, in addition to the lower socioeconomic groups, females also identified significantly more often with seizure disorder than epilepsy and this finding may be related to the impact of social factors, such as stigma. Finally, there are likely cultural factors and beliefs that influenced the preference for reporting seizure disorder over epilepsy which require additional study in this diverse geographic area. The main limitations of the study, in particular the low response rate of 37%, are provided in a previous report [13]. In addition, if we had not
4. Discussion Overall, approximately 75% of all primary survey respondents living in DC with a history of epilepsy, as defined by the BRFSS epilepsy
B.L. Kroner et al. / Epilepsy & Behavior 62 (2016) 214–217
provided separate answer choices for both seizure disorder and epilepsy in our screening question, it is not clear how many of the self-reported seizure disorder cases would have responded negatively had only response choices of Yes and No been provided to the question “Ever diagnosed with epilepsy or a seizure disorder?”. Further investigation is warranted to determine whether predictable subgroups with epilepsy, particularly those that are most vulnerable with active disease, are more likely to self-report that they have never been diagnosed with epilepsy or seizure disorder. In a report of patients with confirmed epilepsy, the prevalence of self-reported epilepsy based on one screening question was compared with that from a series of nine questions. The authors found that females and respondents who were older and less educated had a lower self-reported prevalence than their counterparts in each category [15]. These same three subgroups were found in our study to have significantly lower self-reported epilepsy rates than seizure disorder rates. In addition, further research is needed to explore why Hispanic populations report substantially less epilepsy as well as less seizure disorder, and whether use of different and more culturally appropriate terminology would yield different results.
5. Conclusions Whether the differential self-identification of epilepsy was intentional, to avoid potential stigma, or whether it was a lack of fundamental understanding regarding the name and nature of the diagnosis for a variety of reasons, our findings suggest that both terms need to be addressed with patients in clinical practice to ensure compliance to treatment and disease management. Some clinicians may prefer to use the term seizure disorder with their patients rather than epilepsy, especially when there is an underlying condition such as trauma or stroke, but patients should understand the synonymy of the terms, particularly because of the preponderance of epilepsy-specific information available to the public and on the internet. Epilepsy education and awareness campaigns that are aimed at improving access-to-care and self-management, reducing stigma, and increasing awareness of adverse events such as SUDEP, must include a more diverse definition of epilepsy in their messages in order to reach the broadest population of affected individuals, many of which are in high risk socioeconomic groups that can most benefit from the message content. In addition, researchers must be mindful of the demographic, socioeconomic and cultural diversity of the target population in population-based studies, as such characteristics may dramatically influence the self-reporting of epilepsy. Consideration should be given to using culturally appropriate terminology to define the disorder or adding additional screening questions to improve the sensitivity [16].
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Acknowledgements Funding: This work was supported by the Centers for Disease Control and Prevention (CDC) through the Association for Prevention Teaching and Research (APTR) [Cooperative Agreement, No. 5U50CD300860, Project TS-1389]. The findings and conclusions in this paper are those of the authors and do not necessarily represent the views of the CDC or the APTR. Conflict of interest The authors declare that they have no conflict of interest. References [1] Jacoby A, Austin JK. Social stigma for adults and children with epilepsy. Epilepsia 2007;48:6–9. [2] DiIorio C, Osborne Shafer P, Letz R, Henry T, Schomer DL, Yeager K. Project EASE Study Group. The association of stigma with self-management and perceptions of health care among adults with epilepsy. Epilepsy Behav 2003;4:259–67. [3] Sirven JI, Lopez RA, Vazquez B, Van Haverbeke P. Que es la epilepsia? Attitudes and knowledge of epilepsy by Spanish-speaking adults in the United States. Epilepsy Behav 2005;7:259–65. [4] Kobau R, Gilliam F, Thurman DJ. Prevalence of self-reported epilepsy or seizure disorder and its associations with self-reported depression and anxiety: results from the 2004 HealthStyles Survey. Epilepsia 2006;47:1915–21. [5] Kobau R, Zahran H, Grant D, Thurman DJ, Price PH, Zack MM. Prevalence of active epilepsy and health-related quality of life among adults with self-reported epilepsy in California: California Health Interview Survey, 2003. Epilepsia 2007;48:1904–13. [6] Kobau R, Zahran H, Thurman DJ, et al. Epilepsy surveillance among adults—19 states, Behavioral Risk Factor Surveillance System, 2005. MMWR Surveill Summ 2008;57: 1–20. [7] Kobau R, Luo Y, Zack M, Helmers S, Thurman D. Epilepsy in adults and access to care — United States, 2012. MMWR Surveill Summ 2012;61:909–13. [8] Banerjee PN, Filippi D, Hauser WA. The descriptive epidemiology of epilepsy — a review. Epilepsy Res 2009;85:31–45. [9] Brooks DR, Avetisyan R, Jarrett KM, et al. Validation of self-reported epilepsy for purposes of community surveillance. Epilepsy Behav 2012;23:57–63. [10] Hirtz D, Thurman DJ, Gwinn-Hardy K, Mohammed M, Chaudhuri AR, Zalutsky R. How common are the “common” neurological disorders? Neurology 2007;68: 326–37. [11] Haerer AF, Anderson DW, Schoenberg BS. Prevalence and clinical features of epilepsy in a biracial United States population. Epilepsia 1986;27:66–75. [12] Kelvin EA, Hesdorffer DC, Bagiella E, et al. Prevalence of self-reported epilepsy in a multiracial and multiethnic community in New York City. Epilepsy Res 2007;77: 141–50. [13] Kroner BL, Fahimi M, Kenyon A, Thurman DJ, Gaillard WD. Racial and socioeconomic disparities in epilepsy in the District of Columbia. Epilepsy Res 2013;103:279–87. [14] US Census Bureau. American Community Survey 1-Year Estimate, Summary Tables S0201 and B03002. http://factfinder.census.gov; 2009. [Accessed September 6, 2011]. [15] Banerjee PN, Hauser WA. Incidence and prevalence. In: Engel Jr J, Pedley TA, editors. Epilepsy: a comprehensive textbook. 2nd ed. Philadelphia: Lippincott Williams & Wilkins; 2008. p. 45–56. [16] Ottman R, Barker-Cummings C, Leibson CL, Vasoli VM, Hauser WA, Buchhalter JR. Validation of a brief screening instrument for the ascertainment of epilepsy. Epilepsia 2010;51:191–7.
Contents lists available at ScienceDirect
Epilepsy & Behavior journal homepage: www.elsevier.com/locate/yebeh
Brief Communication
Epilepsy or seizure disorder? The effect of cultural and socioeconomic factors on self-reported prevalence Barbara L. Kroner a,⁎, Mansour Fahimi b, William D. Gaillard c, Anne Kenyon d, David J. Thurman e,1 a
RTI International, Biostatistics and Epidemiology Division, 6110 Executive Boulevard, Rockville, MD 20852, USA GfK Custom Research, LLC Marketing & Data Sciences, Wayne, PA, USA Children's National Health Systems, Division of Epilepsy and Neurophysiology, 111 Michigan Avenue NW, Washington, DC 20010, USA d RTI International, Survey Research Division, 3040 Cornwallis Road, Research Triangle Park, NC 27709, USA e Center for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, 1600 Clifton Road, Atlanta, GA 30329, USA b c
a r t i c l e
i n f o
Article history: Received 4 June 2016 Revised 5 July 2016 Accepted 6 July 2016 Available online xxxx Keywords: Seizure disorder Prevalence Race Self-report Cultural bias Stigma
a b s t r a c t Self-reported epilepsy may be influenced by culture, knowledge, and beliefs. We screened 6420 residents of the District of Columbia (DC) for epilepsy to investigate whether socio-demographics were associated with whether they reported their diagnosis as epilepsy or as seizure disorder. Lifetime and active prevalence rates were 0.54% and 0.21%, respectively for ‘epilepsy’ and 1.30% and 0.70%, respectively for ‘seizure disorder’. Seizure disorder was reported significantly more often than epilepsy among blacks, females, respondents ≥ 50 years, those with lower level education, respondents who lived alone and in low income neighborhoods, and those who resided in DC for at least five years. Clinicians should assure that patients and caregivers understand that epilepsy is synonymous with seizure disorder and other culturally appropriate terms, in order to optimize compliance with treatment, disease management instructions, and utilization of other resources targeted at persons with epilepsy. Furthermore, education and awareness campaigns aimed at improving access-to-care, reducing stigma, and increasing awareness of adverse events, such as SUDEP, should include a more diverse definition of epilepsy in their messages. © 2016 Elsevier Inc. All rights reserved.
1. Introduction For many individuals, the term ‘epilepsy’ is a complex and frightening diagnosis that is associated with social stigma. Some persons identify themselves as having a ‘seizure disorder’ rather than ‘epilepsy,’ although neurologists generally recognize these terms as equivalent in meaning. A diagnosis using either term can have far-reaching implications, particularly when it comes to self-identifying with the condition in some circumstances or populations, such as those in lower income brackets or with uncontrolled seizures [1,2]. Cultural dynamics may also play a role in self-reporting, either directly or indirectly, particularly in racially and economically diverse populations. For instance, Sirven et al. [3] found that 21% of Spanish-speaking adults in the US had no familiarity with the term epilepsy, and over 77% referred to seizures as convulsions or attacks. ⁎ Corresponding author at: RTI International, 6110 Executive Boulevard, Rockville, MD 20852, USA. E-mail addresses: [email protected] (B.L. Kroner), [email protected] (M. Fahimi), [email protected] (W.D. Gaillard), [email protected] (A. Kenyon), [email protected] (D.J. Thurman). 1 Present address: Emory University, School of Medicine, 540 Asbury Circle, Atlanta, GA 30322, USA.
http://dx.doi.org/10.1016/j.yebeh.2016.07.013 1525-5050/© 2016 Elsevier Inc. All rights reserved.
The lifetime prevalence of self-reported epilepsy in communitydwelling adults in the US has ranged from 1.2% to 2.9% [4–7]. The differences across studies may be influenced by survey mode effects (e.g., mailed surveys versus random digit dial telephone surveys) as well as differences in culture and knowledge and beliefs about epilepsy that affect the sensitivity and specificity of self-reporting. For example, false negative cases due to recall bias, untruthful responses because of stigma, or a misinterpretation or misunderstanding of the question being asked will generally go uncounted and result in underestimation of the prevalence. Conversely, false positive cases, such as those that have experienced only provoked, febrile, or psychogenic nonepileptic seizures artificially increase the prevalence estimates. The latter can often be resolved through record-based validation studies; however, population-based studies do not always include this component. In reports of validation of self-reported epilepsy, population-based studies based on self-reports do indeed provide prevalence rates that are higher than clinical record-based studies with few exceptions [8–10]. In the Behavioral Risk Factor Surveillance Surveys (BRFSS) conducted in 19 States, a nonstatistically significant higher prevalence of epilepsy was found in Blacks compared with Whites [6]. Although also not statistically significant, a higher prevalence of self-reported epilepsy among Blacks compared with Whites was found in a biracial area of
B.L. Kroner et al. / Epilepsy & Behavior 62 (2016) 214–217
Mississippi when a more extensive set of survey questions was used [11] and in a multiracial community in New York City [12]. We conducted a population-based survey in the District of Columbia (DC), one of the most culturally, racially, and economically diverse populations in the nation, to estimate the prevalence and incidence of epilepsy in various demographic categories, as defined by either the clinical term epilepsy or the more generic term seizure disorder. Using the combined definition, we found that the epilepsy prevalence in non-Hispanic blacks was twice that found in non-Hispanic whites, after adjusting for age and education [13]. Here we report on the prevalence and incidence of epilepsy and seizure disorder, separately, within the adults that completed the screening survey, to demonstrate that subpopulations of affected persons are more likely to identify their condition as seizure disorder as opposed to epilepsy.
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reported a total of 581,847 residents for the entire DC [14]. The 2009 census data coincided with the time of sample selection and are consistent with those used in the previous report. Findings presented for highest education level completed, which include graduate school, were restricted to the 6128 primary respondents at least 25 years of age. This is consistent with the age restriction used by the U.S. Census for reporting results on educational attainment. In a second phase of the study, cases were mailed another survey which asked about employment, quality of life, comorbidities, seizure type, severity, frequency, and duration, treatment, and whether the case had ever had seizures as a result of a fever, head injury, drug or alcohol use, a stroke, or an acquired medical condition. This survey was used to categorize the etiology of the seizures and the confirmation of epilepsy by the study team neurologist (WDG) [13].
2. Material and methods 3. Results The full description of the study methods are described elsewhere [13]. Briefly, we used the Computerized Delivery Sequence File (CDSF) of the US Postal Service, the most complete address database available in the US providing near perfect coverage, as the sampling frame to select a representative sample of 20,000 household addresses in DC. In order to increase the number of respondents in the analytical subgroups of interest, including Black and non-Black residents in the highest and lowest income strata, households in certain Census Block Groups were over-sampled according to the allocation summarized in Table 1. A single page bi-lingual epilepsy screening questionnaire was then mailed to the probability-based sample of 20,000 households in DC. The survey and the corresponding letter of invitation, which included a statement of informed consent, were approved by the institutional review board for protection of human subjects at RTI International. Nonrespondents to the first wave were mailed a second survey or called on the telephone by a trained interviewer. The survey instructions called for a complete enumeration of all household members, including their demographic characteristics. The instructions also stated that the person completing the survey should be listed on the form as the first member of the household, and hereafter we refer to this person as the primary respondent. For this report, we included only the information corresponding to the primary respondent, realizing that the proxy information on the other household members provided by the primary respondent would be influenced by their attitude and knowledge regarding the terms epilepsy and seizure disorder. The first epilepsy screening question on the survey was derived from the Behavioral Risk Factor Surveillance System's (BRFSS) epilepsy module [6] and asked “Ever diagnosed with epilepsy or a seizure disorder?” with response options: No, Yes epilepsy, and Yes seizure disorder. Three response options were included to maximize the chance of identifying all possible cases of epilepsy in a single question in our culturally diverse population. Active epilepsy or seizure disorder was defined as a positive response to the second screening question “Currently taking any medicine to control seizures?”. All response data were weighted to reflect the sampling design and compensate for differential nonresponse and coverage. The population totals included in the weighting procedures were obtained from the 2009 Current Population Survey, which
There were 6447 primary respondents (6420 adults) that returned the screening survey for an overall adjusted response rate of 36.6%. The demographic composition of the adult primary respondents is presented in Table 2. There were more females (60.5%) than males (39.5%) and slightly more Blacks (45.2%) than Whites (44.4%). Half of the adult study population was at least 50 years of age and 39.7% had attended at least some graduate school. Primary respondents accounted for 107 (61.5%) of the 208 total cases of epilepsy or seizure disorder reported in 201 households. Weighted estimates and 95% confidence intervals for individual lifetime prevalence in the adult primary respondents were 0.54% (0.34–0.74) for epilepsy and 1.30% (0.98–1.62) for seizure disorder for an overall lifetime prevalence of 1.84% (1.47–2.21) for either condition. Adult primary respondents with active epilepsy were also significantly more likely to identify their condition as a seizure disorder than as epilepsy—0.70% (0.47–0.94) versus 0.21% (0.08–0.33). Of the 6420 primary respondents that were at least 18 years of age, the demographic characteristics by history of each self-reported condition are presented in Table 2. Lifetime prevalence of seizure disorder was reported more often than epilepsy in all primary respondent subgroups except those age 18–30 years. The comparative rates for seizure disorder ranged from almost equal compared with epilepsy to three times higher than that reported for epilepsy. The prevalence of seizure disorder was significantly higher than epilepsy among non-Hispanic Blacks, females, those 50 years of age or older, those with only a high school education, those living in low income neighborhoods, and those who resided in DC for at least five years. Prevalence results for active seizure disorder and active epilepsy by demographic subgroups are presented in Table 3, and in all subgroups the rates were higher for self-reported seizure disorder than they were for self-reported epilepsy. The prevalence of active seizure disorder was significantly higher than the prevalence of active epilepsy among the same six subgroups identified for lifetime prevalence and included non-Hispanic Blacks, females, those 50 years of age or older, those with only a high school education, those living in low income neighborhoods, and those who resided in DC for at least five years. In four subgroups (young adults, Hispanic, race other than White or
Table 1 Distribution of all households in DC and in the sample by percent Blacks and median household income from Census. Percent Blacks in CBG
N95% 70–94% 10–69% b10% Total
Median household income for census block group Less than $30,000
$30,000–$39,999
$40,000–$49,999
More than $49,999
Total
DC
Sample
DC
Sample
DC
Sample
DC
Sample
DC
Sample
15.2% 8.8% 4.5% 0.5% 29.0%
18.0% 5.2% 2.6% 3.7% 29.5%
6.9% 7.7% 6.3% 1.6% 22.5%
8.1% 4.5% 3.7% 1.9% 18.2%
1.2% 4.4% 3.8% 3.8% 13.2%
1.4% 2.6% 2.3% 4.5% 10.8%
1.2% 3.9% 8.8% 21.4% 35.3%
8.7% 2.3% 5.2% 25.3% 41.5%
24.5% 24.8% 23.4% 27.3% 100.0%
36.2% 14.6% 13.8% 35.4% 100.0%
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Table 2 Demographics of primary respondents with a history of self-identified epilepsy and selfidentified seizure disorder. Sample sizea
% history of epilepsy or seizure disorder (95% CI)
% history of epilepsy only (95% CI)
% history of seizure disorder only (95% CI)
6420
1.84 (1.47–2.21)
0.54 (0.34–0.74)
1.30 (0.98–1.61)
Gender Male Female
2539 3881
1.92 (1.31–2.53) 1.79 (1.32–2.25)
0.67 (0.32–1.04) 0.45 (0.22–0.67)
1.24 (0.75–1.74) 1.34 (0.93–1.75)
Age 18–30 years 30–49 years ≥50 years
947 2265 3208
0.88 (0.27–1.50) 1.80 (1.20–2.41) 2.19 (1.60–2.79)
0.46 (0.02–0.91) 0.55 (0.23–0.87) 0.56 (0.26–0.87)
0.42 (0–0.85) 1.26 (0.74–1.78) 1.63 (1.12–2.14)
2851
1.12 (0.73–1.52)
0.48 (0.22–0.75)
0.64 (0.34–0.94)
2903
2.53 (1.89–3.18)
0.64 (0.32–0.97)
1.89 (1.33–2.45)
309 357
0.96 (0–1.95) 1.47 (0.02–2.93)
0.26 (0–0.77) 0.29 (0–0.86)
0.71 (0–1.56) 1.18 (0–2.52)
4.69 (2.21–7.17)
1.19 (0–2.57)
3.50 (1.41–5.60)
2.63 (1.48–3.79)
0.31 (0–0.68)
2.33 (1.23–3.42)
2.04 (1.39–2.68) 0.78 (0.43–1.13)
0.86 (0.46–1.27) 0.17 (0.01–0.32)
1.17 (0.67–1.68) 0.61 (0.29–0.93)
Census block income b$30K 1554 $30K–$49K 2026 $50K or more 2840
3.08 (2.16–4.01) 1.13 (0.64–1.62) 1.45 (0.97–1.92)
0.74 (0.28–1.21) 0.24 (0.02–0.46) 0.68 (0.35–1.01)
2.34 (1.53–3.14) 0.89 (0.45–1.32) 0.77 (0.43–1.10)
Years lived in DC b5 1387 5 or more 5033
0.83 (0.31–1.34) 2.11 (1.66–2.56)
0.38 (0–0.75) 0.59 (0.35–0.82)
0.45 (0.10–0.80) 1.52 (1.13–1.91)
All primary respondents
Race/ethnicity White, non-Hispanic Black, non-Hispanic Hispanic Other
Highest educationb Less than high 327 school High school 860 graduate College 2393 Graduate 2548 school
Table 3 Demographics of primary respondents currently taking medication to control seizures and with a history of self-identified epilepsy and self-identified seizure disorder. Sample sizea
% active epilepsy or seizure disorder (95% CI)
% active epilepsy only (95% CI)
% active seizure disorder only (95% CI)
6420
0.91 (0.64–1.18)
0.21 (0.08–0.33)
0.70 (0.47–0.94)
Gender Male Female
2539 3881
0.95 (0.52–1.38) 0.88 (0.54–1.23)
0.38 (0.10–0.66) 0.08 (0–0.17)
0.57 (0.24–0.90) 0.80 (0.47–1.13)
Age 18–30 years 30–49 years ≥50 years
947 2265 3208
0.16 (0–0.46) 0.81 (0.38–1.25) 1.25 (0.80–1.69)
0 0.16 (0–0.36) 0.31 (0.10–0.53)
0.16 (0–0.46) 0.65 (0.26–1.04) 0.93 (0.54–1.32)
2851
0.43 (0.18–0.69)
0.18 (0.02–0.35)
0.25 (0.06–0.44)
2903
1.33 (0.86–1.80)
0.27 (0.06–0.48)
1.06 (0.64–1.49)
309 357
0.58 (0–1.40) 0.75 (0–1.79)
0 0
0.58 (0–1.40) 0.75 (0–1.79)
3.01 (0.94–5.07)
1.16 (0–2.51)
1.85 (0.26–3.43)
1.47 (0.62–2.32)
0.19 (0–0.53)
1.28 (0.55–2.14)
0.84 (0.43–1.25) 0.39 (0.13–0.65)
0.30 (0.05–0.46) 0.07 (0–0.16)
0.54 (0.21–0.82) 0.32 (0.08–0.56)
Census block income b$30K 1554 $30K–$49K 2026 $50K or more 2840
1.66 (0.95–2.36) 0.51 (0.19–0.84) 0.64 (0.32–0.95)
0.24 (0–0.53) 0.14 (0–0.30) 0.25 (0.04–0.45)
1.41 (0.77–2.06) 0.38 (0.10–0.66) 0.39 (0.15–0.63)
Years lived in DC b5 1387 5 or more 5033
0.10 (0–0.30) 1.12 (0.79–1.46)
0 0.26 (0.10–0.42)
0.11 (0–0.30) 0.86 (0.57–1.16)
All primary respondents
Race/ethnicity White, non-Hispanic Black, non-Hispanic Hispanic Other
Highest educationb Less than high 327 school High school 860 graduate College 2393 Graduate 2548 school
Bold means the percentage of people reporting a history of seizure disorder is significantly higher than the percentage of people reporting a history of epilepsy. a Number of unweighted observations. b Among those at least 25 years of age.
Bold means the percentage of people reporting active seizure disorder is significantly higher than the percentage of people reporting active epilepsy. a Number of unweighted observations. b Among those at least 25 years of age.
Black, and those residing in DC for less than 5 years), all of the affected primary respondents identified their condition as seizure disorder. Additional surveys about epilepsy and seizure history were completed by 70 (65.4%) of the 107 primary respondent cases, of which 22 (31.4%) identified their condition as epilepsy and 48 (68.6%) identified their condition as seizure disorder. Symptomatic causes for the seizures that we specified in the survey were found in 35 (50%) and were significantly more prevalent in those with self-reported seizure disorder compared with those with self-reported epilepsy [29 (60.4%) versus 6 (27.3%), p = .02]. Specific causes in the seizure disorder and epilepsy groups, respectively, were trauma only (18.8% versus 13.6%), stroke only (6.3% versus 4.5%), drugs or alcohol only (10.4% versus 0%), trauma plus stroke, alcohol or drug use (12.5% versus 4.5%) and chronic medical condition such as multiple sclerosis, hypertension, congenital arteriovenous malformation, migraines, and brain tumor (12.5% versus 4.5%). In the overall group of 19 adult cases with seizures due to trauma, three had gunshot wounds to the head. Small numbers limited the ability to calculate weighted prevalence rates for the symptomatic cases stratified by demographic characteristics.
surveillance screening question, identified their condition as a seizure disorder rather than epilepsy when provided with the two options. Primary respondents were also more likely to identify their condition as a seizure disorder than as epilepsy in each of the demographic subgroups, and significantly more seizure disorder than epilepsy was reported in several subgroups related to lower socioeconomic status, for both prevalent and active disease. The consistently higher self-identification with seizure disorder over epilepsy across all subgroups, including the highly educated, suggests that those with seizure disorder are unlikely to be false positive cases of epilepsy. We demonstrated that there was significantly more symptomatic epilepsy in the seizure disorder group compared with the epilepsy group which may partially explain our findings. Some people may be more inclined to think that epilepsy is the diagnosis when there is no known cause for the seizures. In particular, trauma was associated with seizures in 27% of the primary respondents with epilepsy in DC compared with less than 9% reported by others [15]. However, in addition to the lower socioeconomic groups, females also identified significantly more often with seizure disorder than epilepsy and this finding may be related to the impact of social factors, such as stigma. Finally, there are likely cultural factors and beliefs that influenced the preference for reporting seizure disorder over epilepsy which require additional study in this diverse geographic area. The main limitations of the study, in particular the low response rate of 37%, are provided in a previous report [13]. In addition, if we had not
4. Discussion Overall, approximately 75% of all primary survey respondents living in DC with a history of epilepsy, as defined by the BRFSS epilepsy
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provided separate answer choices for both seizure disorder and epilepsy in our screening question, it is not clear how many of the self-reported seizure disorder cases would have responded negatively had only response choices of Yes and No been provided to the question “Ever diagnosed with epilepsy or a seizure disorder?”. Further investigation is warranted to determine whether predictable subgroups with epilepsy, particularly those that are most vulnerable with active disease, are more likely to self-report that they have never been diagnosed with epilepsy or seizure disorder. In a report of patients with confirmed epilepsy, the prevalence of self-reported epilepsy based on one screening question was compared with that from a series of nine questions. The authors found that females and respondents who were older and less educated had a lower self-reported prevalence than their counterparts in each category [15]. These same three subgroups were found in our study to have significantly lower self-reported epilepsy rates than seizure disorder rates. In addition, further research is needed to explore why Hispanic populations report substantially less epilepsy as well as less seizure disorder, and whether use of different and more culturally appropriate terminology would yield different results.
5. Conclusions Whether the differential self-identification of epilepsy was intentional, to avoid potential stigma, or whether it was a lack of fundamental understanding regarding the name and nature of the diagnosis for a variety of reasons, our findings suggest that both terms need to be addressed with patients in clinical practice to ensure compliance to treatment and disease management. Some clinicians may prefer to use the term seizure disorder with their patients rather than epilepsy, especially when there is an underlying condition such as trauma or stroke, but patients should understand the synonymy of the terms, particularly because of the preponderance of epilepsy-specific information available to the public and on the internet. Epilepsy education and awareness campaigns that are aimed at improving access-to-care and self-management, reducing stigma, and increasing awareness of adverse events such as SUDEP, must include a more diverse definition of epilepsy in their messages in order to reach the broadest population of affected individuals, many of which are in high risk socioeconomic groups that can most benefit from the message content. In addition, researchers must be mindful of the demographic, socioeconomic and cultural diversity of the target population in population-based studies, as such characteristics may dramatically influence the self-reporting of epilepsy. Consideration should be given to using culturally appropriate terminology to define the disorder or adding additional screening questions to improve the sensitivity [16].
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Acknowledgements Funding: This work was supported by the Centers for Disease Control and Prevention (CDC) through the Association for Prevention Teaching and Research (APTR) [Cooperative Agreement, No. 5U50CD300860, Project TS-1389]. The findings and conclusions in this paper are those of the authors and do not necessarily represent the views of the CDC or the APTR. Conflict of interest The authors declare that they have no conflict of interest. References [1] Jacoby A, Austin JK. Social stigma for adults and children with epilepsy. Epilepsia 2007;48:6–9. [2] DiIorio C, Osborne Shafer P, Letz R, Henry T, Schomer DL, Yeager K. Project EASE Study Group. The association of stigma with self-management and perceptions of health care among adults with epilepsy. Epilepsy Behav 2003;4:259–67. [3] Sirven JI, Lopez RA, Vazquez B, Van Haverbeke P. Que es la epilepsia? Attitudes and knowledge of epilepsy by Spanish-speaking adults in the United States. Epilepsy Behav 2005;7:259–65. [4] Kobau R, Gilliam F, Thurman DJ. Prevalence of self-reported epilepsy or seizure disorder and its associations with self-reported depression and anxiety: results from the 2004 HealthStyles Survey. Epilepsia 2006;47:1915–21. [5] Kobau R, Zahran H, Grant D, Thurman DJ, Price PH, Zack MM. Prevalence of active epilepsy and health-related quality of life among adults with self-reported epilepsy in California: California Health Interview Survey, 2003. Epilepsia 2007;48:1904–13. [6] Kobau R, Zahran H, Thurman DJ, et al. Epilepsy surveillance among adults—19 states, Behavioral Risk Factor Surveillance System, 2005. MMWR Surveill Summ 2008;57: 1–20. [7] Kobau R, Luo Y, Zack M, Helmers S, Thurman D. Epilepsy in adults and access to care — United States, 2012. MMWR Surveill Summ 2012;61:909–13. [8] Banerjee PN, Filippi D, Hauser WA. The descriptive epidemiology of epilepsy — a review. Epilepsy Res 2009;85:31–45. [9] Brooks DR, Avetisyan R, Jarrett KM, et al. Validation of self-reported epilepsy for purposes of community surveillance. Epilepsy Behav 2012;23:57–63. [10] Hirtz D, Thurman DJ, Gwinn-Hardy K, Mohammed M, Chaudhuri AR, Zalutsky R. How common are the “common” neurological disorders? Neurology 2007;68: 326–37. [11] Haerer AF, Anderson DW, Schoenberg BS. Prevalence and clinical features of epilepsy in a biracial United States population. Epilepsia 1986;27:66–75. [12] Kelvin EA, Hesdorffer DC, Bagiella E, et al. Prevalence of self-reported epilepsy in a multiracial and multiethnic community in New York City. Epilepsy Res 2007;77: 141–50. [13] Kroner BL, Fahimi M, Kenyon A, Thurman DJ, Gaillard WD. Racial and socioeconomic disparities in epilepsy in the District of Columbia. Epilepsy Res 2013;103:279–87. [14] US Census Bureau. American Community Survey 1-Year Estimate, Summary Tables S0201 and B03002. http://factfinder.census.gov; 2009. [Accessed September 6, 2011]. [15] Banerjee PN, Hauser WA. Incidence and prevalence. In: Engel Jr J, Pedley TA, editors. Epilepsy: a comprehensive textbook. 2nd ed. Philadelphia: Lippincott Williams & Wilkins; 2008. p. 45–56. [16] Ottman R, Barker-Cummings C, Leibson CL, Vasoli VM, Hauser WA, Buchhalter JR. Validation of a brief screening instrument for the ascertainment of epilepsy. Epilepsia 2010;51:191–7.