Sudep Risk Is High In Severe Childhood Epilepsies

What was studied

This study combined data from 37 randomized clinical trials and 15 long-term extension studies in people with developmental and epileptic encephalopathies, or DEEs. In total, 3,757 patients were included: 2,221 with Lennox-Gastaut syndrome (LGS), 998 with Dravet syndrome (DS), 369 with infantile epileptic spasms syndrome (IESS), and 169 with other DEEs.

The researchers estimated how often death from any cause happened and how often sudden unexpected death in epilepsy (SUDEP) happened. They used a statistical method called a Bayesian meta-analysis to pool results across studies and estimate rates per 1,000 person-years, which means the number of events expected over time in a group of people.

What they found

Across all included studies, there were 37 deaths. These included 2 definite SUDEP cases, 12 probable SUDEP cases, and 1 possible SUDEP case.

For the overall DEE group, the estimated death rate from any cause was 8.76 per 1,000 person-years, and the estimated SUDEP rate was 4.32 per 1,000 person-years. By syndrome, the estimated all-cause death rate was 7.05 per 1,000 person-years in LGS, 8.0 in DS, and 9.41 in IESS. The estimated SUDEP rate was 3.4 per 1,000 person-years in LGS, 7.59 in DS, and 2.79 in IESS.

SUDEP was estimated to account for about half of deaths in the overall DEE group and in LGS. In DS, SUDEP was estimated to make up a proportionally greater share of deaths.

Limits of the evidence

This study pooled data from clinical trials, not from the general population. People in trials may be followed more closely and may not represent everyone with these syndromes.

The authors note that the rates may be underestimated because features of trial-based datasets could have contributed to lower observed mortality and SUDEP estimates. The number of deaths was also small, which adds uncertainty to the estimates. Because this was a meta-analysis of existing studies, it cannot define the real-world incidence as accurately as prospective population-based studies.

For families and caregivers

For families, this study adds evidence that premature death and SUDEP are important concerns in DEEs, including LGS, DS, and IESS. It also suggests that SUDEP may account for a substantial share of deaths in these trial-based datasets, with a proportionally greater contribution in Dravet syndrome.

At the same time, these numbers come from trial data and may not show the full real-world picture. The study is most useful for understanding overall estimated patterns in these conditions, not for predicting an individual child’s risk.

What to watch next

Prospective population-based studies are needed to more accurately define the real-world incidence of SUDEP in DEEs.

Terms in this summary

developmental and epileptic encephalopathies (DEEs)

A group of severe epilepsy disorders that affect seizures, development, and brain function.

SUDEP

Sudden unexpected death in epilepsy, when a person with epilepsy dies suddenly and no other clear cause is found.

meta-analysis

A study that combines results from many studies to get an overall estimate.

randomized clinical trial

A study that tests treatments by assigning people to groups in a planned way.

open-label extension study

A follow-up study after a trial in which participants usually know what treatment they are getting.

person-years

A way to measure time in a study by combining how many people took part and how long each person was followed.

Bayesian

A statistical approach that combines study data with prior information to estimate likely results.

credible interval

A range that shows the uncertainty around an estimate in a Bayesian analysis.