Increased Risk of Dementia after Transient Global Amnesia: A Nationwide Population-Based, Longitudinal Follow-Up Study in South Korea.

ABSTRACT

INTRODUCTION: The long-term cognitive outcomes after transient global amnesia (TGA) have been contradictory in the literature. Our study aimed to longitudinally investigate the association between TGA and incident dementia using long-term data from a nationwide population-based cohort in South Korea. METHODS: The study population was recruited between 2002 and 2020 using the International Classification of Diseases (Tenth Revision; ICD-10) codes from the Korean National Health Insurance Service database. The cumulative incidence curve was plotted to compare the incidence of dementia between the TGA (ICD-10 code G45.4; n = 10,276) and non-TGA (n = 27,389) groups, determined using 13 propensity score matching. Using Cox proportional hazard regression models, we obtained crude and adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for the incident dementia in patients with TGA compared to non-TGA controls. To examine independent variables determining dementia in the TGA group, logistic regression analysis was performed, and adjusted odds ratios (aORs) and 95% CIs were calculated. RESULTS: The TGA group had a significantly higher cumulative incidence of dementia than the non-TGA group (p < 0.001, log-rank test). TGA was significantly associated with incident dementia in the univariate and multivariate Cox models (HR 1.34, 95% CI 1.28-1.39 and aHR 1.40, 95% CI 1.34-1.46, respectively). The adjusted logistic regression for incident dementia in the TGA group showed that age (per 1 year, aOR 1.09, 95% CI 1.09-1.10), female sex (aOR 1.31, 95% CI 1.18-1.45), diabetes (aOR 1.21, 95% CI 1.08-1.35), stroke (aOR 1.30, 95% CI 1.16-1.46), depression (aOR 1.53, 95% CI 1.33-1.76), anxiety (aOR 1.24, 95% CI 1.01-1.39), and rural residence (aOR 1.24, 95% CI 1.10-1.41) were independently associated with incident dementia. CONCLUSION: Our results suggest a longitudinal association of TGA with incident dementia.