Mortality in people with epilepsy: A statewide retrospective cohort study

People with epilepsy (PWE) have a higher risk of mortality than the general population, because of disparities in the receipt of appropriate epilepsy care, which may be affected by socioeconomic status, race/ethnicity and insurance coverage. Increased epilepsy prevalence has been associated with black race, low educational attainment, unemployment, and low income levels. Rural/urban residence may affect health through individual or environmental factors. Health disparities seen in rural residents are likely amplified in rural PWE because of limited access to specialized care. This analysis aims to examine the risk of mortality attributable to rural residence in the statewide population of South Carolina (SC) after adjusting for potential confounders.

This statewide retrospective cohort study of PWE seen in SC non-federal hospitals and emergency departments from 2000 to 2013 describes the hazard of mortality by rural/urban residential status in addition to other demographic and clinical characteristics. Differences in proportions were assessed by comparison of 95% confidence intervals. The association of rural/urban residence with mortality was further evaluated with Cox proportional hazard regression controlling for demographic and clinical covariables.

62,794 PWE were identified, of whom 21,451 (25.7%) had died. Deceased PWE were more likely to be rural residents, black, older than age 45, Medicare insured, in the middle income group, and have 5 or more comorbid conditions compared with living PWE. After adjustment for all other covariables, the risk of mortality did not differ by rural/urban residence. Blacks had a weak but significantly higher risk than whites (hazard ratio (HR)=1.14; 95% confidence interval (CI)=1.11, 1.18) while PWE of other races had a slightly lower risk of mortality (HR=0.79; 95% CI=0.67, 0.93). Male PWE had higher hazard as did Medicare, Medicaid or commercially insured PWE, those living in zip codes with annual median incomes less than $36,000, and those with 2 or more comorbid conditions.

While other covariables were more strongly associated with mortality after adjustment (older age, insurance coverage, income level of zip code, and number of comorbidities), the finding of a higher hazard in black PWE than white PWE after adjustment for rural/urban residence and other demographic and clinical covariables is a concern. Further, the increased risk of mortality with higher numbers of comorbid conditions warrants regular management of these conditions.