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Background A higher risk of developing dementia is observed in patients with atrial fibrillation (AF). Results are inconsistent regarding the risk of dementia when patients with AF use different anticoagulants. We aimed to investigate the risk of dementia in patients with AF receiving non‐vitamin K antagonist oral anticoagulants (NOACs) compared with those receiving warfarin. Methods and Results We conducted a nationwide population‐based cohort study of incident cases using the Taiwan National Health Insurance Research Database. We initially enlisted all incident cases of AF and then selected those treated with either NOACs or warfarin for at least 90 days between 2012 and 2016. First‐ever diagnosis of dementia was the primary outcome. We performed propensity score matching to minimize the difference between each cohort. We used the Fine and Gray competing risk regression model to calculate the hazard ratio (HR) for dementia. We recruited 12 068 patients with AF (6034 patients in each cohort). The mean follow‐up time was 3.27 and 3.08 years in the groups using NOACs and warfarin, respectively. Compared with the HR for the group using warfarin, the HR for dementia was 0.82 (95% CI, 0.73–0.92; P =0.0004) in the group using NOACs. Subgroup analysis demonstrated that users of NOAC aged 65 to 74 years, with a high risk of stroke or bleeding were associated with a lower risk of dementia than users of warfarin with similar characteristics. Conclusions Patients with AF using NOACs were associated with a lower risk of dementia than those using warfarin. Further randomized clinical trials are greatly needed to prove these findings.

Background Warfarin, a vitamin K antagonist, has been shown to affect bone mineral density and cause osteoporosis. However, studies investigating the relationship between non–vitamin K antagonist oral anticoagulants ( NOAC s) and osteoporosis are limited. We thus compared the risk of osteoporosis in patients with atrial fibrillation treated with either NOAC s or warfarin. Methods and Results This nationwide, retrospective cohort study used Taiwan's National Health Insurance Research Database. All adult patients in Taiwan who were newly diagnosed with atrial fibrillation and treated with NOAC s or warfarin between January 2012 and December 2015 were included and classified into their respective cohorts. Patients who received NOAC s were subcategorized into the rivaroxaban, dabigatran, and apixaban subgroups. Propensity score matching was performed for each head‐to‐head comparison. Adjusted hazard ratios ( aHR s) for the risk of osteoporosis were calculated using Cox proportional hazards regression models, with adjustment for confounders. Overall, 17 008 patients were included, with 8504 in each cohort. NOAC s were associated with a lower osteoporosis risk than warfarin ( aHR =0.82; 95% CI=0.68–0.97). A subgroup effect of treatment duration was identified (namely, the lower osteoporosis risk with NOAC compared with warfarin became stronger in those with longer treatment duration [ P for interaction aHR =0.68; 95% CI =0.55–0.83) and apixaban ( aHR =0.38; 95% CI =0.22–0.66) subgroups, but not in the dabigatran subgroup ( aHR =1.04; 95% CI =0.85–1.27). Conclusions Compared with warfarin, rivaroxaban and apixaban were associated with a significantly lower risk of osteoporosis in patients with atrial fibrillation.

Background The effect of holiday season admission for stroke on mortality has not been investigated. Thus, we aimed to evaluate whether “holiday season” and “weekend” effects exist on mortality risk for stroke admission. Methods and Results A nationwide cohort study was conducted using Taiwan's National Health Insurance Research Database. We identified all patients admitted for stroke between 2011 and 2015 in Taiwan, and categorized them according to the admission date: holiday season (at least 4 days off) (n=3908), weekend (n=13 774), and weekday (n=49 045). We analyzed in‐hospital, 7‐day, and 30‐day mortality using multivariable logistic regression, adjusting for stroke severity and other confounders. Compared with weekday admissions, holiday season admission for stroke was significantly associated with a 20%, 33%, and 21% increase in in‐hospital, 7‐day, and 30‐day mortality, respectively. Compared with weekend admissions, holiday season admissions were associated with a 24%, 30%, and 22% increased risk of in‐hospital, 7‐day, and 30‐day mortality, respectively. However, mortality did not differ significantly between weekend and weekday admissions. Subanalyses after stratification for age, sex, and stroke type also revealed similar trends. Conclusions We report for the first time a “holiday season effect” on stroke mortality. Patients admitted during holiday seasons had higher mortality risks than those admitted on weekends and weekdays. This holiday season effect persisted even after adjusting for stroke severity and other important confounders. These findings highlight the need for healthcare delivery systems with a consistent quality of round‐the‐clock care for patients admitted for stroke.