Epilepsy Incidence, Prevalence Greater in More Deprived UK Regions

Prevalence and incidence of epilepsy in the United Kingdom was shown to be broadly in line with other high-income counties, with trends indicating significant geographical variation and a potential relationship between the disease and deprivation. Results were published in Seizure: European Journal of Epilepsy.

As the fourth most common neurological disorder after Alzheimer disease, migraine, and stroke, epilepsy, a complex disease comprising a spectrum of brain disorders that can cause seizures, has estimated incidence (50-80 per 100,000 person-years) and prevalence rates (5-10 per 1000 person/year) that are relatively consistent across high-income countries.

Researchers noted that demographics and risk factors, such as age, general practitioner (GP) and specialist training, and obstetric care, have been shown in recent years to potentially contribute to increases or decreases in the incidence and prevalence of epilepsy in certain geographic areas, which help inform many aspects of health service planning.

With the most recent estimates of these parameters for the United Kingdom published over a decade ago, the study authors sought to investigate the epidemiology of epilepsy and to explore temporal changes in the country and its constituent nations (England, Northern Ireland, Scotland, and Wales). Three key metrics were explored regarding the epidemiology of epilepsy in the United Kingdom specifically:

• Estimation of the incidence and prevalence of epilepsy by year, age group, gender, country (England, Scotland, Wales, and Northern Ireland) and region (England)
• Estimation of the incidence and prevalence of epilepsy by practice-level deprivation decile, using the appropriate national Index of Multiple Deprivation (IMD) scale
• Characterization of the changes in prevalence and incidence rates since 2011
  

For the analysis, data were derived from primary care practices contributing to the Clinical Practice Research Datalink (CRPD), based on the electronic health records of 14 million patients, representing approximately 20% of the population. The study period was January 1, 2013, to December 31, 2018.

“[GPs] play a key role in the UK health care system, as they are responsible for most primary health care, maintaining national disease registers, making specialist referrals, and monitoring long-term treatment,” explained the study authors. “CPRD contains data from 2 different health record systems: the Vision clinical system (CPRD GOLD database) and the EMIS Web clinical system (CPRD Aurum database).”

In 2020, data on the source population used from the CPRD GOLD database included 3,138,215 individuals registered with 83 GP practices in England, 179 practices in Scotland, 101 practices in Wales, and 35 practices in Northern Ireland (accessed September 11, 2020). In the same year, the source population from the CPRD Aurum database included 11,802,119 individuals registered with 1233 GP practices in England and 11 practices in Northern Ireland (accessed September 11, 2020).

Findings showed that the estimated overall point prevalence for epilepsy in the United Kingdom was 9.37 per 1000 persons/year (95% CI, 9.34-9.40) and the overall estimated incidence rate was 42.68 per 100,000 person-years (95%, 42.18-43.18) using the CPRD GOLD database.

The estimated incidence and prevalence was lower in England compared with other constituent nations within the United Kingdom:

• Using combined databases, the estimated incidence and prevalence of epilepsy in England was 37.41 (95% CI, 36.96-37.83) and 8.85 (95% CI, 8.83-8.87), respectively
• Using CPRD GOLD only, the estimated incidence and prevalence of epilepsy in Scotland was 47.76 (95% CI, 46.15-49.42) and 10.13 (95% CI, 10.06-10.20), respectively
• Using CPRD GOLD only, the estimated incidence and prevalence of epilepsy in Wales was 54.84 (95% CI, 52.79-56.95) and 11.40 (95% CI, 11.31-11.49), respectively
• Using combined databases, the estimated incidence and prevalence of epilepsy in Northern Ireland was 46.18 (95% CI, 43.13-49.90) and 12.08 (95% CI, 11.93-12.23), respectively

Furthermore, IMD metrics showed higher incidence and prevalence of epilepsy in more deprived regions.

Prevalence by practice level IMD decile showed a clear trend of increasing prevalence with successive levels of deprivation, increasing from a prevalence of 7.86 per 1000 (95% CI, 7.74-7.99) in the lowest IMD decile (1, least deprived) to a prevalence of 12.07 per 1000 (95% CI, 11.93-12.20) in the highest IMD decile (10, most deprived) in the CPRD GOLD database (all of the United Kingdom) with a similar picture seen in the CPRD Aurum database (England and Northern Ireland only).

Incidence by practice level IMD decile mirrored that seen for prevalence, with incidence rates increasing from the least deprived, 35.6 per 100,000 persons-years (95% CI, 32.88-38.48), to the most deprived, 58.35 per 100,000 persons-years (95% CI, 55.32-61.50), in the CPRD GOLD database (all of the United Kingdom), with a similar picture seen in the CPRD Aurum database (England and Northern Ireland).

Increasing levels of social deprivation were highly correlated with epilepsy incidence (r = 0.68) and prevalence (CPRD GOLD, r = 0.97; CPRD Aurum, r = 0.93) rates.

“Although our figures indicate that the prevalence of epilepsy has fallen slightly relative to 2011, the estimates generated by our analysis are significantly higher than prevalence figures used by Public Health England for national healthcare planning purposes,” concluded the researchers. “Our findings provide further support for the correlation between the incidence (and prevalence) and social deprivation, with an almost 40% increase in the incidence (and prevalence) from the lowest to the highest deprivation decile.”

Reference

Wigglesworth S, Neligan A, Dickson JM, et al. The incidence and prevalence of epilepsy in the United Kingdom 2013–2018: a retrospective cohort study of UK primary care data. Seizure. 2023 Jan 5;105:37-42. doi:10.1016/j.seizure.2023.01.003