The Long-Term Risk of Dementia after Transient Global Amnesia: A Population-Based Cohort Study in Taiwan.

Background: Transient global amnesia (TGA) is a clinical syndrome characterized by the sudden onset of larger anterograde and milder retrograde amnesia that lasts up to 24 h. Objectives: We aimed to investigate the long-term risk of dementia up to 8 years in subjects with TGA. Method: We conducted a control cohort study using the Taiwan National Health Insurance Research database from 2005 to 2012 with an 8-year follow-up period. From all potential participants >18 years of age without dementia history, we identified TGA subjects and non-TGA controls with age, gender and comorbidities matched in a 1:3 ratio. The yearly incidence of dementia was compared in TGA and non-TGA cohorts. The cumulative hazard ratio (HR) of dementia was estimated. The risk factors of dementia after TGA were investigated. Results: A total of 181 TGA subjects and 543 non-TGA controls were included in the study. There were 14 dementia cases in the 181 TGA cohorts during the follow-up period with yearly incidence rates of 20.14 per 1,000 person. The adjusted HR for dementia in TGA cohorts was 2.23 (95% CI 1.12-4.44, p = 0.023) compared with non-TGA cohorts after adjusting for age, gender and comorbidities. Age and diabetes were significantly associated with dementia in TGA. Conclusions: TGA increased the long-term risk of dementia. Age and diabetes were notable factors associated with dementia after TGA.