P2-527: prevalence and incidence of seizures and epilepsy in the oldest-old with and without dementia: the monzino 80-plus population-based study

Population-based studies investigating the association of dementia and seizures/epilepsy are rare. Estimates are needed for rational management and prevention strategies for seizures in dementia. Aim of the study was to estimate the prevalence and incidence of seizures/epilepsy among the 80-years and older residents in Varese province, Italy, participating in the Monzino 80-plus prospective population-based study. At each visit, history of seizures and epilepsy, and anti-epileptic drug use (AEDs) was ascertained administering a standardized questionnaire to the participant and primary informant, usually a family member. Diagnosis of dementia was made according to DSM-IV criteria. At first visit, information on history of seizures/epilepsy was available from 2,192 80 years and older participants (mean age: 90.2 years; mean education: 5.1 years; women 72.8%: in institution: 16.2%). Prevalence of seizures and epilepsy in the overall population was very similar: 1.6% (95%CI: 1.1−2.1; n=34) and 1.3% (95%CI: 0.8−1.8; n=28), respectively. Prevalence was significantly higher in oldest-old with dementia (2.8% [95%CI: 1.7−3.9; n=23] and 2.2% [95%CI: 1.2−3.2; n=18]) than in those without (0.8% [95%CI: 0.3−1.3; n=11] and 0.7% [95%CI: 0.3−1.1; n=10]; OR adjusted for age, sex and education: 5.0, 95%CI: 2.3−11.0, p<0.0001 for seizures; 4.8, 95%CI: 2.1−11.2, p=0.0003 for epilepsy). Among persons with dementia and a history of seizures, 11 (47.8%) were in a severe, 10 (43.5%) in a moderate, and 2 (8.7%) in a mild stage. Twenty out 34 participants with seizures/epilepsy were taking AEDs (7 without and 13 with dementia, adjusted OR: 4.9, 95%CI: 1.8−13.4, p=0.0021). Among the 1,984 participants without seizures/epilepsy and not taking AEDs at baseline, and with at least one follow-up available (726 with and 1,258 without dementia), annual incidence of seizures during the following 15 years (on average: 2.4 and 5.1 years, respectively for individuals with and without dementia) was: 0.6‰ in oldest-old with dementia (1 case, 1,747 person-years) and 1.3‰ in those without (8 cases, 6,364 person-years). Among 80-years and older participants in the present prospective population-based study, prevalence of seizures/epilepsy was significantly higher in oldest-old with dementia than in those without. During 15 years of follow-up, incidence of seizures was uncommon in both groups.