Case-control study developing Scottish Epilepsy Deaths Study Score to predict epilepsy-related death

This study aimed to develop a risk prediction model for epilepsy-related death in adults. In this age- and sex-matched case-control study, we compared adults (aged ≥16 years) who had epilepsy-related death between 2009 and 2016 to living adults with epilepsy in Scotland. Cases were identified from validated administrative national datasets linked to mortality records. ICD-10 cause-of-death coding was used to define epilepsy-related death. Controls were recruited from a research database and epilepsy clinics. Clinical data from medical records were abstracted and used to undertake univariable and multivariable conditional logistic regression to develop a risk prediction model consisting of four variables chosen a priori. A weighted sum of the factors present was taken to create a risk index—the Scottish Epilepsy Deaths Study Score. Odds ratios were estimated with 95% confidence intervals (CIs). Here, 224 deceased cases (mean age 48 years, 114 male) and 224 matched living controls were compared. In univariable analysis, predictors of epilepsy-related death were recent epilepsy-related accident and emergency attendance (odds ratio 5.1, 95% CI 3.2–8.3), living in deprived areas (odds ratio 2.5, 95% CI 1.6–4.0), developmental epilepsy (odds ratio 3.1, 95% CI 1.7–5.7), raised Charlson Comorbidity Index score (odds ratio 2.5, 95% CI 1.2–5.2), alcohol abuse (odds ratio 4.4, 95% CI 2.2–9.2), absent recent neurology review (odds ratio 3.8, 95% CI 2.4–6.1) and generalized epilepsy (odds ratio 1.9, 95% CI 1.2–3.0). Scottish Epilepsy Deaths Study Score model variables were derived from the first four listed before, with Charlson Comorbidity Index ≥2 given 1 point, living in the two most deprived areas given 2 points, having an inherited or congenital aetiology or risk factor for developing epilepsy given 2 points and recent epilepsy-related accident and emergency attendance given 3 points. Compared to having a Scottish Epilepsy Deaths Study Score of 0, those with a Scottish Epilepsy Deaths Study Score of 1 remained low risk, with odds ratio 1.6 (95% CI 0.5–4.8). Those with a Scottish Epilepsy Deaths Study Score of 2–3 had moderate risk, with odds ratio 2.8 (95% CI 1.3–6.2). Those with a Scottish Epilepsy Deaths Study Score of 4–5 and 6–8 were high risk, with odds ratio 14.4 (95% CI 5.9–35.2) and 24.0 (95% CI 8.1–71.2), respectively. The Scottish Epilepsy Deaths Study Score may be a helpful tool for identifying adults at high risk of epilepsy-related death and requires external validation.