Incidence and risk of seizures in Alzheimer's disease: A nationwide population-based cohort study

Abstract

The reported incidence and risk factors mediating seizures in Alzheimer's disease (AD) have been extremely inconsistent and relevant data is lacking in Asia. We investigated the incidence rate and risk of seizures in AD and in a large, nationwide cohort from Han Chinese. A retrospective population-based study was conducted on the data from Taiwan's National Health Insurance Research Database from 2000 to 2010. To reduce selection bias, we applied propensity scores, wherein 981 patients with AD were matched to 3835 non-AD controls from a pool of 1000,000 randomly sampled cohort dataset. This approach was based on age, sex, comorbidities and previous brain conditions. Incidence rate, cumulative incidence and hazard ratios (HRs) were estimated. During the 10-year follow-up period (mean follow-up time, 4.02 years), 44 out of 937 AD patients (4.7%) developed seizures. The incidence rate in the AD cohort (11.9 per 1000 person-years) was higher than that in the matched cohort (5.7 per 1000 person-years), with an adjusted HR of 1.85 (95% confidence interval [CI], 1.20-2.83, p=0.005). The mean duration from the diagnosis of AD to the occurrence of seizure is 3.6 years. The Cox regression analysis revealed that AD itself is a significant predictor after adjustment for confounders (HR=2.01, 95% CI, 1.40-2.90, p<0.001). Moreover, age is an independent predictor, with an adjusted HR of 1.03 (95% CI, 1.00-1.05, p=0.019). In conclusion, seizure occurrence in AD is more common than in the matched cohort. Notably, advanced age carries a higher risk for development of seizures in patients with AD.

Keywords: Alzheimer's disease; Asia; Incidence; Seizures.