Aims: Atrial fibrillation (AF) is generally regarded as a risk factor for dementia, though longitudinal studies assessing the association between AF and dementia have shown inconsistent results. This study aimed to determine the effect of AF on the risk of developing dementia using a longitudinal, community-based, and stroke-free elderly cohort. Methods and results: The association of incident AF with the development of incident dementia was assessed from 2005 to 2012 in 262 611 dementia- and stroke-free participants aged ≥60 years in the Korea National Health Insurance Service-Senior cohort. Incident AF was observed in 10 435 participants over an observational period of 1 629 903 person-years (0.64%/year). During the observational period, the incidence of dementia was 4.1 and 2.7 per 100 person-years in the incident AF and propensity score-matched AF-free groups, respectively. After adjustment, the risk of dementia was significantly increased by incident AF with a hazard ratio (HR) of 1.52 [95% confidence interval (CI) 1.43–1.63], even after censoring for stroke (1.27, 95% CI 1.18–1.37). Incident AF increased the risk of both Alzheimer (HR 1.31, 95% CI 1.20–1.43) and vascular dementia (HR 2.11, 95% CI 1.85–2.41). Among patients with incident AF, oral anticoagulant use was associated with a preventive effect on dementia development (HR 0.61, 95% CI 0.54–0.68), and an increasing CHA2DS2-VASc score was associated with a higher risk of dementia. Conclusion: Incident AF was associated with an increased risk of dementia, independent of clinical stroke in an elderly population. Oral anticoagulant use was linked with a decreased incidence of dementia.

Most data on the clinical epidemiology of atrial fibrillation (AF) are reported from Western populations, and data for Asians are limited. We aimed to investigate the 10-year trends of the prevalence and incidence of non-valvular AF and provide prevalence projections till 2060 in Korea. We also investigated the annual risks of adverse outcomes among patients with AF. Using the Korean National Health Insurance Service database involving the entire Korean population, a total of 679,416 adults with newly diagnosed AF were identified from 2006 to 2015. The incidence and prevalence of AF and risk of adverse outcomes following AF onset were assessed. The prevalence of AF progressively increased by 2.10-fold from 0.73% in 2006 to 1.53% in 2015. The trend of its incidence was flat with a 10-year overall incidence of 1.77 per 1,000 person-years. The prevalence of AF is expected to reach 5.81% (2,290,591 patients with AF) in 2060. For a decade, the risk of all-cause mortality following AF declined by 30% (adjusted hazard ratio [HR]: 0.70, 95% confidence interval [CI]: 0.68-0.72), heart failure by 52% (adjusted HR: 0.48, 95% CI: 0.44-0.51), and ischemic stroke by 9% (adjusted HR: 0.91, 95% CI: 0.88-0.93). The burden of AF among Asian patients is increasing. Although the overall risks of cardiovascular events and death following AF onset have decreased over a decade, the event rates are still high. Optimized management of any associated comorbidities should be part of the holistic management approach for patients with AF.

Aims: Accumulating evidence shows that atrial fibrillation (AF) is associated with an increased risk of dementia. Catheter ablation for AF prolongs the duration of sinus rhythm, thereby improving the quality of life. We investigated the association of catheter ablation for AF with the occurrence of dementia. Methods and results: Using the Korean National Health Insurance Service database, among 194 928 adults with AF treated with ablation or medical therapy (antiarrhythmic or rate control drugs) between 1 January 2005 and 31 December 2015, we studied 9119 patients undergoing ablation and 17 978 patients managed with medical therapy. The time-at-risk was counted from the first medical therapy, and ablation was analysed as a time-varying exposure. Propensity score-matching was used to correct for differences between the groups. During a median follow-up of 52 months, compared with patients with medical therapy, ablated patients showed lower incidence and risk of overall dementia (8.1 and 5.6 per 1000 person-years, respectively; hazard ratio 0.73, 95% confidence interval 0.58–0.93). The associations between ablation and dementia risk were consistently observed after additionally censoring for incident stroke (hazard ratio 0.76, 95% confidence interval 0.61–0.95) and more pronounced in cases of ablation success whereas no significant differences observed in cases of ablation failure. Ablation was associated with lower risks of dementia subtypes including Alzheimer’s disease and vascular dementia. Conclusion: In this nationwide cohort of AF patients treated with catheter ablation or medical therapy, ablation was associated with decreased dementia risk. This relationship was evident after censoring for stroke and adjusting for clinical confounders.

There are a paucity of data on the association of duration of hypertension and blood pressure (BP) level with risk of ischaemic stroke in patients with atrial fibrillation (AF). Our objective was to investigate the association between duration of hypertension and secondly, BP levels with risk of ischaemic stroke among patients with AF. A total of 246 459 oral anticoagulant-naïve non-valvular AF patients were enrolled from Korea National Health Insurance Service (NHIS) database (2005-2015). The risk of ischaemic stroke according to the duration of hypertension and systolic BP (SBP) levels were assessed. One-year increase of hypertension duration continuously increased the adjusted risk of ischaemic stroke (95% confidence interval 1.07-1.09) until 7 years, and reached a plateau with adjusted hazard ratio of 1.6. Risk of ischaemic stroke increased linearly with the increase of hypertension duration in patients younger than 65 years of age, whereas the risk reached a plateau in patients aged 65 years or older. In all baseline and pre-AF average SBP subgroups, longer duration of hypertension before AF was associated with higher ischaemic stroke risk than shorter duration of hypertension (all P-values for trends <0.01). However, the effect of long-term hypertension was not observed in patients with strictly well-controlled pre-AF average SBP of less than 120 mmHg. The increase of hypertension duration was associated with the increased risk of ischaemic stroke. However, this long-term effect of hypertension duration can be attenuated by long-term strict SBP control throughout the entire duration of hypertension.

Background Stroke risk in atrial fibrillation (AF) is often assessed at initial presentation, and risk stratification performed as a ‘one off’. In validation studies of risk prediction, baseline values are often used to ‘predict’ events that occur many years later. Many clinical variables have ‘dynamic’ changes over time, as the patient is followed up. These dynamic changes in risk factors may increase the CHA₂DS₂-VASc score, stroke risk category and absolute ischaemic stroke rate. Objective This article evaluates the ‘dynamic’ changes of CHA₂DS₂-VASc variables and its effect on prediction of stroke risk. Patients and Methods From the Korea National Health Insurance Service database, a total of 167,262 oral anticoagulant-naive non-valvular AF patients aged ≥ 18 years old were enrolled between January 1, 2002, and December 31, 2005. These patients were followed up until December 31, 2015. Results At baseline, the proportions of subjects categorized as ‘low’, ‘intermediate’ or ‘high risk’ by CHA₂DS₂-VASc score were 15.4, 10.6 and 74.0%, respectively. Mean CHA₂DS₂-VASc score increased annually by 0.14, particularly due to age and hypertension. During follow-up of 10 years, 46.6% of ‘low-risk’ patients and 72.0% of ‘intermediate risk’ patients were re-classified to higher stroke risk categories. Among the original ‘low-risk’ patients, annual ischaemic stroke rates were significantly higher in the re-classified ‘intermediate’ (1.17 per 100 person-years, p < 0.001) or re-classified ‘high-risk’ groups (1.44 per 100 person-years, p = 0.048) than consistently ‘low-risk’ group (0.29 per 100 person-years). The most recent CHA₂DS₂-VASc score and the score change with the longest follow-up had the best prediction for ischaemic stroke. Conclusion In AF patients, stroke risk as assessed by the CHA₂DS₂-VASc score is dynamic and changes over time. Rates of ischaemic stroke increased when patients accumulated risk factors, and were re-classified into higher CHA₂DS₂-VASc score categories. Stroke risk assessment is needed at every patient contact, as accumulation of risk factors with increasing CHA₂DS₂-VASc score translates to greater stroke risks over time. Minjae Yoon and Pil-Sung Yang contributed equally to the article. Gregory Y. H. Lip and Boyoung Joung are senior co-authors of the article. M. Yoon and P.S. Yang drafted the manuscript, had full access to all of the data and takes responsibility for the integrity of the data and the accuracy of the data analysis. E. Jang, H.T. Yu, T.H. Kim, J.S. Uhm, J.Y. Kim, H.N. Pak and M.H. Lee contributed to data collection. B. Joung and G.Y.H.L. contributed to data interpretation, critical revision and final approval of the manuscript.