Calculate

This tool analysis epilepsy risk following a first posttraumatic seizure (PTS). The study utilized a register-based cohort design and included 4,239 individuals with a first seizure, of whom 2,286 had a prior traumatic brain injury (TBI) and 1,953 served as non-TBI controls. Data were sourced from Swedish national healthcare and population registers, covering hospitalizations for TBI between 2000 and 2010, with follow-up extending up to 10 years (median: 2.0 years). The median age was 51 years in the TBI group and 67 years in the non-TBI group. High diagnostic accuracy (over 90%) was achieved through the use of validated registry data.

Variables Used:

TBI Severity and Classification:
Participants were categorized into six levels of TBI severity based on ICD-10 diagnostic codes:

1. Non-TBI (Control Group): No history of traumatic brain injury.
2. Mild TBI: Minimal or transient symptoms, coded as S060.
3. Fracture: Skull fractures without direct evidence of brain injury, coded as S020, S021, S027, S029.
4. Extracerebral Injury: External injuries such as scalp or cranial damage, coded as S064, S065, S066.
5. Diffuse Cerebral Injury: Widespread brain injuries, including concussions or cerebral edema, coded as S061, S062, S067-S069.
6. Focal Cerebral Injury: Localized brain injuries, such as contusions or hematomas, coded as S063, associated with the highest risk of epilepsy.

Time Interval in Months:
The time from TBI to the first PTS was categorized into less than two years and more than two years. Earlier seizures (<2 years) were associated with a significantly higher risk of subsequent epilepsy.

Comorbidities:
The analysis also accounted for key co-variates, including stroke, CNS tumors, and CNS infections, which can influence the risk of epilepsy following a first PTS.

Outputs:

Risk of Seizure Recurrence:
This tool provides individualized risk estimates for epilepsy following a first PTS, stratified by TBI severity and the time interval since the injury.
Example: Patients with focal cerebral injuries and seizures occurring within two years post-TBI have a substantially elevated risk of seizure recurrence compared to those with mild TBI or seizures occurring more than two years after the injury.

COSY (Chance of an Occurrence of a Seizure in the next Year):
COSY quantifies the probability of experiencing another seizure within the next year, reflecting dynamic changes in seizure risk over time.
Example: For patients with mild TBI, the probability of another seizure decreases over time, whereas it remains consistently high for individuals with severe injuries, particularly focal cerebral injuries, or seizures occurring shortly after the injury.