Contributions: PLL, NC and AA developed the research idea. DSK, RFG and THM were involved with outcome ascertainment. NM and AA conducted the analysis. PLL drafted the manuscript.

Background Only 50% of atrial fibrillation ( AF ) patients recommended for oral anticoagulation ( OAC ) use these medications, and less than half of them adhere to OAC . In a cohort of Medicare beneficiaries newly diagnosed with AF , we identified groups of patients with similar trajectories of OAC use and adherence, and evaluated patient characteristics affecting group membership. Methods and Results We selected continuously enrolled Medicare Part D beneficiaries with first AF diagnosis in 2014 to 2015 (n=34 898). We calculated the proportion of days covered with OAC over the first 12 months after diagnosis and identified OAC adherence trajectories using group‐based trajectory models. We constructed multinomial logistic regression models to evaluate how demographics, system‐level factors, and clinical characteristics were associated with group membership. We identified 4 trajectories of OAC adherence: patients who never used OAC (43.8%), late OAC initiators (7.6%), early OAC discontinuers (8.9%), and continuously adherent patients (40.1%). Predictors such as sex, black race, residence in the South, or HAS ‐ BLED score were associated with not only OAC use, but also the timing of initiation and the likelihood of discontinuation. For example, HAS ‐ BLED score ≥4 was associated with a higher likelihood of not using OAC (odds ratio 1.35; 95% CI , 1.14–1.62), of late initiation (1.55; 95% CI , 1.11–2.05), and of early discontinuation (odds ratio 1.35; 95% CI , 1.01–1.84). Conclusions We identified 4 distinct trajectories of OAC adherence after first AF diagnosis, with <45% of newly diagnosed AF patients belonging to the trajectory group characterized by continuous OAC adherence. Trajectories were associated not only with demographic and clinical characteristics but also with regional factors.

Background: Atrial fibrillation (AF) is the most common heart rhythm disorder and is associated with a 5-fold increased risk of ischemic stroke. Racial/ethnic minorities and women with AF have higher rates of stroke compared to white individuals and men respectively. Oral anticoagulation reduces the risk of stroke, yet prior research has described racial/ethnic and sexbased variation in its use. We sought to examine the initiation of any oral anticoagulant (warfarin

Background Oral anticoagulants ( OACs ) in patients with atrial fibrillation ( AF ), in addition to reducing stroke risk, could also prevent adverse cognitive outcomes. The purpose of this study was to compare the risk of dementia incidence across patients with AF initiating different OAC s. Methods and Results We identified patients with nonvalvular AF initiating OAC s in 2 US healthcare claim databases, MarketScan (2007–2015) and Optum Clinformatics (2009–2015). Dementia, comorbidities, and use of medications were defined on the basis of inpatient and outpatient claims. We performed head‐to‐head comparisons of warfarin, dabigatran, rivaroxaban, and apixaban in propensity score–matched cohorts. We calculated hazard ratios ( HR s) and 95% confidence intervals ( CI s) of incident dementia for each propensity score–matched cohort and meta‐analyzed database‐specific results. We analyzed 307 099 patients with AF from the MarketScan database and 161 346 from the Optum database, of which 6572 and 4391, respectively, had a diagnosis of incident dementia. The mean follow‐up of each cohort ranged between 0.7 and 2.2 years. Patients initiating direct OACs experienced lower rates of dementia than those initiating warfarin (dabigatran: HR , 0.85; 95% CI , 0.71–1.01; rivaroxaban: HR , 0.85; 95% CI , 0.76–0.94; apixaban: HR , 0.80; 95% CI , 0.65–0.97). There were no differences in rates of dementia comparing direct OAC user groups (dabigatran versus rivaroxaban: HR , 1.02; 95% CI , 0.79–1.32; dabigatran versus apixaban: HR , 0.92; 95% CI , 0.63–1.36; apixaban versus rivaroxaban: HR , 1.01; 95% CI , 0.86–1.19). Conclusions Patients with AF initiating direct OACs experienced lower rates of incident dementia than warfarin users. No obvious benefit was observed for any particular direct OAC in relation to dementia rates.

Background Polypharmacy is highly prevalent in elderly people with chronic conditions, including atrial fibrillation ( AF ). The impact of polypharmacy on adverse outcomes and on treatment effectiveness in elderly patients with AF remains unaddressed. Methods and Results We studied 338 810 AF patients ≥75 years of age enrolled in the MarketScan Medicare Supplemental database in 2007–2015. Polypharmacy was defined as ≥5 active prescriptions at AF diagnosis (defined by the presence of International Classification of Diseases, Ninth Revision, Clinical Modification [ ICD‐9‐CM ] codes) based on outpatient pharmacy claims. AF treatments (oral anticoagulation, rhythm and rate control) and cardiovascular end points (ischemic stroke, bleeding, heart failure) were defined based on inpatient, outpatient, and pharmacy claims. Multivariable Cox models were used to estimate associations of polypharmacy with cardiovascular end points and the interaction between polypharmacy and AF treatments in relation to cardiovascular end points. Prevalence of polypharmacy was 52%. Patients with polypharmacy had increased risk of major bleeding (hazard ratio [ HR ], 1.16; 95% CI, 1.12–1.20) and heart failure ( HR , 1.33; 95% CI , 1.29–1.36) but not ischemic stroke ( HR , 0.96; 95% CI , 0.92–1.00), compared with those not receiving polypharmacy. Polypharmacy status did not consistently modify the effectiveness of oral anticoagulants. Rhythm control (versus rate control) was more effective in preventing heart failure hospitalization in patients not receiving polypharmacy ( HR , 0.87; 95% CI , 0.76–0.99) than among those with polypharmacy ( HR , 0.98; 95% CI , 0.91–1.07; P =0.02 for interaction). Conclusion Polypharmacy is common among patients ≥75 with AF , is associated with adverse outcomes, and may modify the effectiveness of AF treatments. Optimizing management of polypharmacy in AF patients ≥75 may lead to improved outcomes.