Abstracts

RATIONALE: To determine mortality and factors influencing it in the long term in a population based cohort with epilepsy METHODS: Methods The UK National General Practice Study of Epilepsy(NGPSE) is a prospective study of 792 patients with epilepsy followed for >11 yrs(median follow-up [25th, 75th centiles] is 11.8 yrs[10.6-11.7]). Standardized mortality ratios(SMRs) were estimated. Multivariate Cox regression and time dependent co-variate analyses were utilised for the first time in a study of mortality in epilepsy RESULTS: Mortality was twice that of the general population(SMR 2.1[95%CI=1.8,2.4]). Patients with acute symptomatic (SMR 3.0[95%CI=2.0,4.3]), remote symptomatic (SMR 3.7,[95%CI 2.9,4.6]) and epilepsy due to congenital neurological deficits(SMR 25[95%CI=5.1,73.1]) had increased mortality whilst patients with idiopathic epilepsy did not(SMR 1.3[95%CI=0.9,1.9]). Patients with tonic clonic seizures had an increased mortality(hazard ratio or HR 6.2[95%CI=1.4,27.7; p=0.049]). Cerebrovascular disease(HR 2.4[95%C=1.7,3.4;p<0.0001]), CNS tumor (HR 12.0 [95%CI=7.9,18.2;p<0.0001]), alcohol (HR 2.9[95%CI=1.5,5.7;p=0.004) and congenital neurological deficits (HR 10.9[95%CI=3.2,36.1;p=0.003]); and older age at index seizure (HR 1.9[95%CI=1.7,2.0; p<0.0001]) also increased mortality. Time dependent co-variate analysis examined seizure recurrence (HR 1.30[95%CI=0.84,2.01]) and AED treatment (HR 0.97 [95%CI=0.67,1.38]); both did not influence mortality. There were only 5 epilepsy related deaths CONCLUSIONS: Mortality in epilepsy in the long term is significantly elevated. Epilepsy due to congenital neurological deficits may carry almost the same risk of mortality as epilepsy due to CNS tumors, and epileptic seizures subsequent to alcohol abuse almost the same risk as epilepsy due to cerebrovascular disease. Tonic clonic seizures may carry an independent risk of mortality whilst seizure recurrence and drug treatment do not appear to influence mortality. This may be a reflection of the heterogeneity of seizure syndromes. Mortality directly due to epileptic seizures is uncommon in a population based cohort