‘Landmark’ study confirms aetiology effect on epilepsy mortality risk

By Eleanor McDermid, Senior medwireNews Reporter

A “landmark” meta-analysis confirms the increased mortality risk in patients who have symptomatic or cryptogenic epilepsy.

The study by Olli Nevalainen (University of Tampere, Finland) and colleagues included data for 165,879 patients from 38 epilepsy cohorts studied over the past 40 years, the majority (79.6%) of whom were from Nordic countries.

Overall, patients’ mortality risk was elevated about threefold relative to the general population, the team reports in Neurology.

However, the risk varied according to the aetiology. Patients with idiopathic epilepsy did not have a significantly increased mortality risk, whereas it was elevated 1.75-fold among patients with cryptogenic epilepsy.

Mortality risk was not elevated among patients with incident epilepsy who achieved freedom from seizures or 5-year terminal remission. There was significant 1.56-fold increase when prevalent cases were included and the risk increase was markedly higher among patients with frequent seizures, at 4.65-fold.

Patients with symptomatic epilepsy had a similar elevation in mortality risk, at 4.48-fold, but the highest risk was for patients who had congenital or developmental causes of epilepsy, at a 10.27-fold increase.

The included patients ranged from infants to the elderly, and the association between aetiology and mortality risk was consistent at all ages.

None of the studies, including the more recent ones, classified epilepsy patients according to the 1989 International League Against Epilepsy (ILAE) proposals, and just two cohorts were based in countries with a low UN Human Development Index.

In an editorial, Patrick Kwan (Royal Melbourne Hospital, Victoria, Australia) and Dennis Dlugos (The Children’s Hospital of Philadelphia, Pennsylvania, USA) say that the field should move on, now that “this landmark meta-analysis has conclusively summarized 4 decades of epidemiology research in the population mortality of epilepsy.”

Future research should focus on the risk factors and mechanisms underlying excess mortality in epilepsy patients, in a bid to develop preventative strategies, they say.

The editorialists believe that future studies should conform to the ILAE definitions, to more accurately define patients with cryptogenic epilepsy, with or without an associated disorder, and should address the role of antiepileptic drugs and gather more data from the developing world.

They suggest that researchers should now harness social media and crowdsourcing to help “to better understand the mechanisms of excess mortality in epilepsy, ultimately leading to effective preventive strategies.”

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