Specialized Epilepsy Care Linked to Lower Premature Mortality

Colin B. Josephson, MD, MSc, assistant professor of neurology, University of Calgary

Colin B. Josephson, MD, MSc

New study results have suggested that patient exposure to specialized care—defined as care by a neurologist or comprehensive epilepsy program (CEP) epileptologist—is associated with a lower hazard of premature mortality in individuals with epilepsy.¹

Overall, the standardized mortality rates for those in the care of a CEP epileptologist and neurologist were 6.6% and 3.8%, respectively, lower than that of those in non-specialist settings. As well, the hazard ratio (HR) was lower for those in the care of a neurologist (HR, 0.85; 95% CI, 0.77-0.93; P <.001) and CEP epileptologist (HR, 0.49; 95% CI, 0.38-0.62; P <.001).

Additionally, an older age at index (HR, 1.06; 95% CI, 1.06-1.06) and severity (based on claims; HR, 1.06; 95% CI, 1.05-1.07) were associated with a greater hazard of mortality. The overall risk of dying is 1.6 to 3 times higher in people with epilepsy than in the general population.²

“The association between the level of specialist care and mortality in epilepsy merits further study,” author Colin B. Josephson, MD, MSc, assistant professor of neurology, University of Calgary, and colleagues wrote. “A prospective cohort study could produce valuable information to help further our understanding of the importance of referral propensity, competing risk of death, and other factors associated with mortality in epilepsy.”

In total, the cohort consisted of 23,653 cases (annual incidence of 89 per 100,000), in which 60% (n = 14,099) were not exposed to specialist care, 40% (n = 9554) received care from a neurologist, and 9% (n = 2054) received care from a CEP epileptologist. A case was considered incident if the participant had a minimum of 3 years without any epilepsy claims or epilepsy admissions before the case definition satisfaction.

There were 5755 deaths, of which 71% (n = 4098) occurred in the group which was not exposed to specialist care. Meanwhile 26% (n = 1481) occurred in the care of a neurologist and 3% (n = 176) occurred in CEP care. The mean age at death in the full cohort was 69.1 (interquartile range [IQR], 17.1), and was 69.8 (IQR, 16.8), 67.8 (IQR, 17.4), and 62.8 (IQR, 17.7) in the non-specialist, neurologist, and CEP groups, respectively.

When removing the 2142 deaths (43%) which occurred in the first 2 years of follow-up, the findings remained consistent—neurologist (HR, 0.85; 95% CI, 0.74-0.98) and CEP (HR, 0.49; 95% CI, 0.38-0.62) referrals were associated with incrementally reduced hazards of premature mortality.

The standardized mortality rate was 7.2% for the whole cohort, while the rates for those receiving non-specialist care, neurologist care, and for CEP care were 9.4%, 5.6%, and 2.8%, respectively. The difference between the 3 adjusted survival curves was highly significant (P <.001).

“The level of specialist referral is associated with an incremental reduction in the risk of premature mortality in patients who receive a diagnosis of incident epilepsy, and the greatest benefit is seen in those referred to a comprehensive epilepsy program,” Josephson and colleagues wrote.

When using propensity models, the investigators found that referrals to neurologists and CEP care had accuracy values of 0.55 and 0.52, respectively. Similar to the entire group, in the propensity-matched cohort, the hazard of mortality was lower when receiving neurologist care (HR, 0.85; 95% CI, 0.74-0.98), as well as CEP care (HR, 0.45; 95% CI, 0.37-0.54) compared with those who did not.

Notably, Josephson and colleagues pointed out that a decrease in mortality has been observed to be associated with specialist care in a number of other conditions, including kidney and cardiac disease. “Improved diagnostic performance and access to treatment options not available outside of specialist care may act as potential drivers of this benefit,” they wrote.

They added that the possibility of a more accurate and speedy diagnosis, a higher likelihood of proper medication selection, experience with polytherapy, and access to epilepsy surgery may all contribute to this association between specialist care and lower mortality as well.

REFERENCES

1. Lowerison MW, Josephson CB, Jette N, et al. Association of levels of specialized care with risk of premature mortality in patients with epilepsy. JAMA Neurol. Published online August 5, 2019. doi: 10.1001/jamaneurol.2019.2268.

2. Institute of Medicine. 2012. Epilepsy Across the Spectrum: Promoting Health and Understanding. Washington, DC: The National Academies Press. doi: 10.17226/13379.