Development and Validation of the DOAC Score: A Novel Bleeding Risk Prediction Tool for Patients With Atrial Fibrillation on Direct-Acting Oral Anticoagulants.

BACKGROUND: Current clinical decision tools for assessing bleeding risk in individuals with atrial fibrillation (AF) have limited performance and were developed for individuals treated with warfarin. This study develops and validates a clinical risk score to personalize estimates of bleeding risk for individuals with atrial fibrillation taking direct-acting oral anticoagulants (DOACs). METHODS: Among individuals taking dabigatran 150 mg twice per day from 44 countries and 951 centers in this secondary analysis of the RE-LY trial (Randomized Evaluation of Long-Term Anticoagulation Therapy), a risk score was developed to determine the comparative risk for bleeding on the basis of covariates derived in a Cox proportional hazards model. The risk prediction model was internally validated with bootstrapping. The model was then further developed in the GARFIELD-AF registry (Global Anticoagulant Registry in the Field-Atrial Fibrillation), with individuals taking dabigatran, edoxaban, rivaroxaban, and apixaban. To determine generalizability in external cohorts and among individuals on different DOACs, the risk prediction model was validated in the COMBINE-AF (A Collaboration Between Multiple Institutions to Better Investigate Non-Vitamin K Antagonist Oral Anticoagulant Use in Atrial Fibrillation) pooled clinical trial cohort and the Quebec Régie de l'Assurance Maladie du Québec and Med-Echo Administrative Databases (RAMQ) administrative database. The primary outcome was major bleeding. The risk score, termed the DOAC Score, was compared with the HAS-BLED score. RESULTS: Of the 5684 patients in RE-LY, 386 (6.8%) experienced a major bleeding event, within a median follow-up of 1.74 years. The prediction model had an optimism-corrected C statistic of 0.73 after internal validation with bootstrapping and was well-calibrated based on visual inspection of calibration plots (goodness-of-fit P=0.57). The DOAC Score assigned points for age, creatinine clearance/glomerular filtration rate, underweight status, stroke/transient ischemic attack/embolism history, diabetes, hypertension, antiplatelet use, nonsteroidal anti-inflammatory use, liver disease, and bleeding history, with each additional point scored associated with a 48.7% (95% CI, 38.9%-59.3%; P<0.001) increase in major bleeding in RE-LY. The score had superior performance to the HAS-BLED score in RE-LY (C statistic, 0.73 versus 0.60; P for difference <0.001) and among 12 296 individuals in GARFIELD-AF (C statistic, 0.71 versus 0.66; P for difference = 0.025). The DOAC Score had stronger predictive performance than the HAS-BLED score in both validation cohorts, including 25 586 individuals in COMBINE-AF (C statistic, 0.67 versus 0.63; P for difference <0.001) and 11 945 individuals in RAMQ (C statistic, 0.65 versus 0.58; P for difference <0.001). CONCLUSIONS: In individuals with atrial fibrillation potentially eligible for DOAC therapy, the DOAC Score can help stratify patients on the basis of expected bleeding risk.

Brain MRI microbleeds and risk of intracranial hemorrhage in atrial fibrillation patients: A Swedish case-control study.

OBJECTIVES: Our goal was to quantify the independent association of brain microbleeds with future intracranial hemorrhage (ICrH). Microbleed findings on brain magnetic resonance imaging (MRI) may identify distinctive risk factors for ICrH which could inform the anticoagulant therapy decision for atrial fibrillation (AF) patients. Our study design includes patients with MRIs for numerous reasons, not limited to evaluation of stroke. MATERIALS AND METHODS: The source population was all patients with AF from a nationwide Swedish health care register. Case patients had an ICrH between 2006 and 2013 and ≥1 brain MRI for an unrelated condition before the ICrH. Each case was matched to four controls who had a brain MRI without a subsequent ICrH. The MRIs were re-reviewed by neuroradiologists. Associations between MRI findings and subsequent ICrH were assessed using logistic regression, adjusting for comorbidities and antithrombotic medications. RESULTS: A total of 78 cases and 312 matched controls were identified; 29 cases and 79 controls had MRI sequences suitable for analysis of microbleeds. Patients with ≥10 microbleeds had a markedly increased risk of ICrH (adjusted odds ratio 14.56; 95 % confidence interval: 2.86-74.16, p < 0.001). All patients with ≥10 microbleeds had microbleeds in the lobar region and ≥10 lobar microbleeds was associated with intracerebral hemorrhages, univariable OR 8.54 (2.01-36.33), p = 0.004. CONCLUSIONS: Leveraging a nationwide database with brain imaging obtained prior to ICrH, we identified a strong association between ≥10 microbleeds on brain MRI and subsequent ICrH among AF patients. Lobar brain regions were involved whenever there were ≥10 microbleeds. Brain MRIs may help optimize the anticoagulation decision in selected AF patients.

Screening for Atrial Fibrillation in Older Adults at Primary Care Visits: VITAL-AF Randomized Controlled Trial.

BACKGROUND: Undiagnosed atrial fibrillation (AF) may cause preventable strokes. Guidelines differ regarding AF screening recommendations. We tested whether point-of-care screening with a handheld single-lead ECG at primary care practice visits increases diagnoses of AF. METHODS: We randomized 16 primary care clinics 1:1 to AF screening using a handheld single-lead ECG (AliveCor KardiaMobile) during vital sign assessments, or usual care. Patients included were ages ≥65 years. Screening results were provided to primary care clinicians at the encounter. All confirmatory diagnostic testing and treatment decisions were made by the primary care clinician. New AF diagnoses during the 1-year follow-up were ascertained electronically and manually adjudicated. Proportions and incidence rates were calculated. Effect heterogeneity was assessed. RESULTS: Of 30 715 patients without prevalent AF (n=15 393 screening [91% screened], n=15 322 control), 1.72% of individuals in the screening group had new AF diagnosed at 1 year versus 1.59% in the control group (risk difference, 0.13% [95% CI, -0.16 to 0.42]; P=0.38). In prespecified subgroup analyses, new AF diagnoses in the screening and control groups were greater among those aged ≥85 years (5.56% versus 3.76%, respectively; risk difference, 1.80% [95% CI, 0.18 to 3.30]). The difference in newly diagnosed AF between the screening period and the previous year was marginally greater in the screening versus control group (0.32% versus -0.12%; risk difference, 0.43% [95% CI, -0.01 to 0.84]). The proportion of individuals with newly diagnosed AF who were initiated on oral anticoagulants was not different in the screening (n=194, 73.5%) and control (n=172, 70.8%) arms (risk difference, 2.7% [95% CI, -5.5 to 10.4]). CONCLUSIONS: Screening for AF using a single-lead ECG at primary care visits did not affect new AF diagnoses among all individuals aged 65 years or older compared with usual care. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03515057.

Detection of Atrial Fibrillation in a Large Population Using Wearable Devices: The Fitbit Heart Study.

BACKGROUND: Morbidity from undiagnosed atrial fibrillation (AF) may be preventable with early detection. Many consumer wearables contain optical photoplethysmography (PPG) sensors to measure pulse rate. PPG-based software algorithms that detect irregular heart rhythms may identify undiagnosed AF in large populations using wearables, but minimizing false-positive detections is essential. METHODS: We performed a prospective remote clinical trial to examine a novel PPG-based algorithm for detecting undiagnosed AF from a range of wrist-worn devices. Adults aged ≥22 years in the United States without AF, using compatible wearable Fitbit devices and Android or iOS smartphones, were included. PPG data were analyzed using a novel algorithm that examines overlapping 5-minute pulse windows (tachograms). Eligible participants with an irregular heart rhythm detection (IHRD), defined as 11 consecutive irregular tachograms, were invited to schedule a telehealth visit and were mailed a 1-week ambulatory ECG patch monitor. The primary outcome was the positive predictive value of the first IHRD during ECG patch monitoring for concurrent AF. RESULTS: A total of 455 699 participants enrolled (median age 47 years, 71% female, 73% White) between May 6 and October 1, 2020. IHRDs occurred for 4728 (1%) participants, and 2070 (4%) participants aged ≥65 years during a median of 122 (interquartile range, 110-134) days at risk for an IHRD. Among 1057 participants with an IHRD notification and subsequent analyzable ECG patch monitor, AF was present in 340 (32.2%). Of the 225 participants with another IHRD during ECG patch monitoring, 221 had concurrent AF on the ECG and 4 did not, resulting in an IHRD positive predictive value of 98.2% (95% CI, 95.5%-99.5%). For participants aged ≥65 years, the IHRD positive predictive value was 97.0% (95% CI, 91.4%-99.4%). CONCLUSIONS: A novel PPG software algorithm for wearable Fitbit devices exhibited a high positive predictive value for concurrent AF and identified participants likely to have AF on subsequent ECG patch monitoring. Wearable devices may facilitate identifying individuals with undiagnosed AF. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT04380415.

Research Opportunities in Stroke Prevention for Atrial Fibrillation: A Report From a National Heart, Lung, and Blood Institute Virtual Workshop.

Atrial fibrillation (AF) is one of the strongest risk factors for ischemic stroke, which is a leading cause of disability and death. Given the aging population, increasing prevalence of AF risk factors, and improved survival in those with cardiovascular disease, the number of individuals affected by AF will continue increasing over time. While multiple proven stroke prevention therapies exist, important questions remain about the optimal approach to stroke prevention at the population and individual patient levels. Our report summarizes the National Heart, Lung, and Blood Institute virtual workshop focused on identifying key research opportunities related to stroke prevention in AF. The workshop reviewed major knowledge gaps and identified targeted research opportunities to advance stroke prevention in AF in the following areas: (1) improving risk stratification tools for stroke and intracranial hemorrhage; (2) addressing challenges with oral anticoagulants; and (3) delineating the optimal roles of percutaneous left atrial appendage occlusion and surgical left atrial appendage closure/excision. This report aims to promote innovative, impactful research that will lead to more personalized, effective use of stroke prevention strategies in people with AF.

Accuracy and variability of cardiologist interpretation of single lead electrocardiograms for atrial fibrillation: The VITAL-AF trial.

BACKGROUND: Screening for atrial fibrillation (AF) using consumer-based devices capable of producing a single lead electrocardiogram (1L ECG) is increasing. There are limited data on the accuracy of physician interpretation of these tracings. The goal of this study is to assess the sensitivity, specificity, confidence, and variability of cardiologist interpretation of point-of-care 1L ECGs. METHODS: Fifteen cardiologists reviewed point-of-care handheld 1L ECGs collected from patients aged 65 years or older enrolled in the VITAL-AF clinical trial [NCT035115057] who underwent cardiac rhythm assessments with a 1L ECG using an AliveCor KardiaMobile device. Random sampling of 1L ECGs for cardiologist review was stratified by the AliveCor algorithm interpretation. A 12L ECG performed on the same day for clinical purposes was used as the gold standard. Cardiologists each reviewed a common sample of 200 1L ECG tracings and completed a survey associated with each tracing. Cardiologists were blinded to both the AliveCor algorithm and same day 12L ECG interpretation. For each tracing, study cardiologists were asked to assess the rhythm (sinus rhythm, AF, unclassifiable), report their assessment of the quality of the tracing, and rate their confidence in rhythm interpretation. The outcomes included the sensitivity, specificity, variability, and confidence in physician interpretation. Variables associated with each measure were identified using multivariable regression. RESULTS: The average sensitivity for AF was 77.4% (range 50%-90.6%, standard deviation [SD]=11.4%) and the average specificity was 73.0% (range 41.3%-94.6%, SD = 15.4%). The mean variability was 30.8% (range 0%-76.2%, SD = 23.2%). The average reviewer confidence of 1L ECG rhythm assessment was 3.6 out of 5 (range 2.5-4.2, SD = 0.6). Patient and tracing factors associated with sensitivity, specificity, variability, and confidence were identified and included age, body mass index, and presence of artifact. CONCLUSION: Cardiologist interpretation of point-of-care handheld 1L ECGs has modest diagnostic sensitivity and specificity with substantial variability for AF classification despite high confidence. Variability in cardiologist interpretation of 1L ECGs highlights the importance of confirmatory testing for diagnosing AF.

Can Treatment Support Mitigate Nicotine Metabolism-Based Disparities in Smoking Abstinence? Secondary Analysis of the Helping HAND 4 Trial.

INTRODUCTION: The nicotine metabolite ratio (NMR), a biomarker of CYP2A6-mediated nicotine metabolism, predicts the efficacy of nicotine replacement therapy (NRT), with fast metabolizers benefiting less than slow metabolizers. Whether treatment support to optimize NRT use (henceforth "treatment support") modifies this pharmacogenetic relationship is unknown. METHODS: Hospitalized adult daily smokers were assigned to one of two post-discharge smoking cessation interventions offering NRT and counseling: (1) Transitional Tobacco Care Management, which delivered enhanced treatment support via free combination NRT at discharge and automated counseling, and (2) a quitline-based approach representing usual care (UC). The primary outcome was biochemically verified 7-day point prevalence abstinence 6 months after discharge. Secondary outcomes were the use of NRT and counseling during the 3-month intervention period. Logistic regression models tested for interactions between NMR and intervention, controlling for sex, race, alcohol use, and BMI. RESULTS: Participants (N = 321) were classified as slow (n = 80) or fast (n = 241) metabolizers relative to the first quartile of NMR (0.012-0.219 vs. 0.221-3.455, respectively). Under UC, fast (vs. slow) metabolizers had lower odds of abstinence at 6 months (aOR 0.35, 95% CI 0.13-0.95) and similar odds of NRT and counseling use. Compared to UC, enhanced treatment support increased abstinence (aOR 2.13, 95% CI 0.98-4.64) and use of combination NRT (aOR 4.62, 95% CI 2.57-8.31) in fast metabolizers, while reducing abstinence in slow metabolizers (aOR 0.21, 95% CI 0.05-0.87; NMR-by-intervention interaction p = .004). CONCLUSIONS: Treatment support increased abstinence and optimal use of NRT among fast nicotine metabolizers, thereby mitigating the gap in abstinence between fast and slow metabolizers. IMPLICATIONS: In this secondary analysis of two smoking cessation interventions for recently hospitalized smokers, fast nicotine metabolizers quit at lower rates than slow metabolizers, but providing fast metabolizers with enhanced treatment support doubled the odds of quitting in this group and mitigated the disparity in abstinence between fast and slow metabolizers. If validated, these findings could lead to personalized approaches to smoking cessation treatment that improve outcomes by targeting treatment support to those who need it most.

Management of Adults with Newly Diagnosed Atrial Fibrillation with and without CKD.

BACKGROUND: Atrial fibrillation (AF) is highly prevalent in CKD and is associated with worse cardiovascular and kidney outcomes. Limited data exist on use of AF pharmacotherapies and AF-related procedures by CKD status. We examined a large "real-world" contemporary population with incident AF to study the association of CKD with management of AF. METHODS: We identified patients with newly diagnosed AF between 2010 and 2017 from two large, integrated health care delivery systems. eGFR (≥60, 45-59, 30-44, 15-29, <15 ml/min per 1.73 m2) was calculated from a minimum of two ambulatory serum creatinine measures separated by ≥90 days. AF medications and procedures were identified from electronic health records. We performed multivariable Fine-Gray subdistribution hazards regression to test the association of CKD severity with receipt of targeted AF therapies. RESULTS: Among 115,564 patients with incident AF, 34% had baseline CKD. In multivariable models, compared with those with eGFR >60 ml/min per 1.73 m2, patients with eGFR 30-44 (adjusted hazard ratio [aHR] 0.91; 95% CI, 0.99 to 0.93), 15-29 (aHR, 0.78; 95% CI, 0.75 to 0.82), and <15 ml/min per 1.73 m2 (aHR, 0.64; 95% CI, 0.58-0.70) had lower use of any AF therapy. Patients with eGFR 15-29 ml/min per 1.73 m2 had lower adjusted use of rate control agents (aHR, 0.61; 95% CI, 0.56 to 0.67), warfarin (aHR, 0.89; 95% CI, 0.84 to 0.94), and DOACs (aHR, 0.23; 95% CI, 0.19 to 0.27) compared with patients with eGFR >60 ml/min per 1.73 m2. These associations were even stronger for eGFR <15 ml/min per 1.73 m2. There was also a graded association between CKD severity and receipt of AF-related procedures (vs eGFR >60 ml/min per 1.73 m2): eGFR 30-44 ml/min per 1.73 (aHR, 0.78; 95% CI, 0.70 to 0.87), eGFR 15-29 ml/min per 1.73 m2 (aHR, 0.73; 95% CI, 0.61 to 0.88), and eGFR <15 ml/min per 1.73 m2 (aHR, 0.48; 95% CI, 0.31 to 0.74). CONCLUSIONS: In adults with newly diagnosed AF, CKD severity was associated with lower receipt of rate control agents, anticoagulation, and AF procedures. Additional data on efficacy and safety of AF therapies in CKD populations are needed to inform management strategies.

Research Priorities in Atrial Fibrillation Screening: A Report From a National Heart, Lung, and Blood Institute Virtual Workshop.

Clinically recognized atrial fibrillation (AF) is associated with higher risk of complications, including ischemic stroke, cognitive decline, heart failure, myocardial infarction, and death. It is increasingly recognized that AF frequently is undetected until complications such as stroke or heart failure occur. Hence, the public and clinicians have an intense interest in detecting AF earlier. However, the most appropriate strategies to detect undiagnosed AF (sometimes referred to as subclinical AF) and the prognostic and therapeutic implications of AF detected by screening are uncertain. Our report summarizes the National Heart, Lung, and Blood Institute's virtual workshop focused on identifying key research priorities related to AF screening. Global experts reviewed major knowledge gaps and identified critical research priorities in the following areas: (1) role of opportunistic screening; (2) AF as a risk factor, risk marker, or both; (3) relationship between AF burden detected with long-term monitoring and outcomes/treatments; (4) designs of potential randomized trials of systematic AF screening with clinically relevant outcomes; and (5) role of AF screening after ischemic stroke. Our report aims to inform and catalyze AF screening research that will advance innovative, resource-efficient, and clinically relevant studies in diverse populations to improve the diagnosis, management, and prognosis of patients with undiagnosed AF.

ReducinG stroke by screening for UndiAgnosed atRial fibrillation in elderly inDividuals (GUARD-AF): Rationale and design of the GUARD-AF randomized trial of screening for atrial fibrillation with a 14-day patch-based continuous ECG monitor.

BACKGROUND: Screening for atrial fibrillation (AF) is attractive because AF independently raises the risk of ischemic stroke, this risk is largely reversible by long-term oral anticoagulant therapy (OAC), and many patients with AF remain undiagnosed and untreated. Recent trials of one-time brief screening for AF have not produced a significant increase in the proportion of patients diagnosed with AF. Trials of longer-term screening have demonstrated an increase in AF diagnoses, primarily paroxysmal AF. To date, however, no trials have demonstrated that screening for AF results in lower rates of stroke. Clinical practice guidelines conflict in their level of support for screening for AF. METHODS: The GUARD-AF individually randomized trial is designed to test whether screening for AF in individuals age 70 years or greater using a 2-week single-lead electrocardiographic patch monitor can identify patients with undiagnosed AF and lead to treatment with OAC, resulting in a reduced rate of stroke in the screened population. The trial's efficacy end point is hospitalization for stroke (either ischemic or hemorrhagic) and the trial's safety end point is hospitalization for a bleeding event. End points will be ascertained via Medicare claims or electronic health records at 2.5 years after study start. Enrollment is based in primary care practices and the OAC decision for screen-detected cases is left to the patient and their physician. The initial planned target sample size was 52,000, with 26,000 allocated to either screening or to usual care. RESULTS: Trial enrollment was severely hampered by the novel coronavirus disease 2019 (COVID-19) pandemic and stopped at a total enrollment of 11,931 participants. Of 5,965 randomized to the screening arm, 5,713 patients (96%) returned monitors with analyzable results. Incidence of screen-detected and clinically detected AF and associated stroke and bleeding outcomes will be ascertained. CONCLUSIONS: GUARD-AF is the largest AF screening randomized trial using a longer-term patch-based continuous electrocardiographic monitor. The results will contribute important information on the yield of patch-based AF screening, the "burden" of AF detected (percent time in AF, longest episode), and physicians' OAC decisions as a function of AF burden. GUARD-AF's stroke and bleed results will contribute to pooled trial analyses of AF screening, thereby informing future studies and guidelines.

Profile of Patients with Isolated Distal Deep Vein Thrombosis versus Proximal Deep Vein Thrombosis or Pulmonary Embolism: RE-COVERY DVT/PE Study.

Isolated distal deep vein thrombosis (IDDVT) is presumed to be more benign than proximal DVT (PDVT) or pulmonary embolism (PE), suggesting a need for different management approaches. This subgroup analysis of the RE-COVERY DVT/PE global, observational study investigated patient characteristics, hospitalization details, and anticoagulant therapy in patients with IDDVT in real-world settings in 34 countries enrolled from January 2016 to May 2017. Data were analyzed descriptively according to the type and location of the index venous thromboembolism (VTE): IDDVT, PDVT ± distal DVT (DDVT), and PE ± DVT. Of the 6,095 eligible patients, 323 with DVT located outside the lower limb and no PE were excluded. Of the remaining 5,772 patients, 17.6% had IDDVT, 39.9% had PDVT ± DDVT, and 42.5% had PE ± DVT. IDDVT patients were younger and had fewer risk factors for VTE than the other groups. Other comorbidities were less frequent in the IDDVT group, except for varicose veins, superficial thrombophlebitis, and venous insufficiency. IDDVT patients were less likely to be diagnosed in an emergency department (22.3 vs. 29.7% for PDVT ± DDVT and 45.4% for PE ± DVT) or hospitalized for VTE (29.2 vs. 48.5% for PDVT ± DDVT and 75.0% for PE ± DVT). At hospital discharge or 14 days after diagnosis (whichever was later), non-vitamin K antagonist oral anticoagulants were the most commonly used anticoagulants (55.6% for IDDVT, 54.7% for PDVT ± DDVT, and 52.8% for PE ± DVT). Although differences in patient characteristics, risk factors, and clinical management were identified, anticoagulant treatment of IDDVT was almost equal to that of PDVT or PE. Prospective studies should investigate whether, in a global perspective, this is an appropriate use of anticoagulants.

Safety and effectiveness of dabigatran in routine clinical practice: the RE-COVERY DVT/PE study.

RE-COVERY DVT/PE is a two-phase, international, observational study of anticoagulant therapy in patients with deep vein thrombosis and/or pulmonary embolism (DVT/PE). The objective of the second phase was to compare the safety and effectiveness of dabigatran versus a vitamin K antagonist (VKA) over 1 year of follow-up. Primary safety and effectiveness outcomes were major or clinically relevant nonmajor bleeding events (MBE/CRNMBEs) and symptomatic recurrent venous thromboembolism (VTE) (including deaths related to recurrent VTE). To minimize bias due to unbalanced patient characteristics, only patients in an overlapping range of estimated propensity scores were included (analytic set), and propensity score weighting was applied to compare outcomes. Outcome analysis used an as-treated approach, censoring patients after they stopped or switched their initial anticoagulant. Overall, 3009 patients enrolled from 2016 to 2018 were eligible: 60% were diagnosed with DVT alone, 21% with PE alone, and 19% with DVT plus PE. The analytic set consisted of 2969 patients. The incidence rate in %/year (95% confidence interval [CI]) of MBE/CRNMBEs was 2.63 (1.79-3.74) with dabigatran versus 4.48 (3.23-6.06) with warfarin; hazard ratio 0.63 (95% CI 0.32-1.25). For symptomatic recurrent nonfatal or fatal VTE the incidence rate was 1.53 (0.91-2.42) with dabigatran versus 2.01 (1.21-3.14) with VKAs; hazard ratio 0.78 (95% CI 0.30-2.02). In conclusion, we found lower annualized rates of MBE/CRNMBEs with dabigatran than VKA, although the difference was not statistically significant. Annualized rates of symptomatic VTE or related mortality were similar with dabigatran and VKA. These observational results with 1 year of follow-up reflect those of the randomized clinical trials. Trial registration: ClinicalTrials.gov identifier NCT02596230, first registered November 4, 2015.

Automated Electronic Phenotyping of Cardioembolic Stroke.

BACKGROUND AND PURPOSE: Oral anticoagulation is generally indicated for cardioembolic strokes, but not for other stroke causes. Consequently, subtype classification of ischemic stroke is important for risk stratification and secondary prevention. Because manual classification of ischemic stroke is time-intensive, we assessed the accuracy of automated algorithms for performing cardioembolic stroke subtyping using an electronic health record (EHR) database. METHODS: We adapted TOAST (Trial of ORG 10172 in Acute Stroke Treatment) features associated with cardioembolic stroke for derivation in the EHR. Using administrative codes and echocardiographic reports within Mass General Brigham Biobank (N=13 079), we iteratively developed EHR-based algorithms to define the TOAST cardioembolic stroke features, revising regular expression algorithms until achieving positive predictive value ≥80%. We compared several machine learning-based statistical algorithms for discriminating cardioembolic stroke using the feature algorithms applied to EHR data from 1598 patients with acute ischemic strokes from the Massachusetts General Hospital Ischemic Stroke Registry (2002-2010) with previously adjudicated TOAST and Causative Classification of Stroke subtypes. RESULTS: Regular expression-based feature extraction algorithms achieved a mean positive predictive value of 95% (range, 88%-100%) across 11 echocardiographic features. Among 1598 patients from the Massachusetts General Hospital Ischemic Stroke Registry, 1068 had any cardioembolic stroke feature within predefined time windows in proximity to the stroke event. Cardioembolic stroke tended to occur at an older age, with more TOAST-based comorbidities, and with atrial fibrillation (82.3%). The best model was a random forest with 92.2% accuracy and area under the receiver operating characteristic curve of 91.1% (95% CI, 87.5%-93.9%). Atrial fibrillation, age, dilated cardiomyopathy, congestive heart failure, patent foramen ovale, mitral annulus calcification, and recent myocardial infarction were the most discriminatory features. CONCLUSIONS: Machine learning-based identification of cardioembolic stroke using EHR data is feasible. Future work is needed to improve the accuracy of automated cardioembolic stroke identification and assess generalizability of electronic phenotyping algorithms across clinical settings.

Rationale and design of a large population study to validate software for the assessment of atrial fibrillation from data acquired by a consumer tracker or smartwatch: The Fitbit heart study.

BACKGROUND: Early detection of atrial fibrillation or flutter (AF) may enable prevention of downstream morbidity. Consumer wrist-worn wearable technology is capable of detecting AF by identifying irregular pulse waveforms using photoplethysmography (PPG). The validity of PPG-based software algorithms for AF detection requires prospective assessment. METHODS: The Fitbit Heart Study (NCT04380415) is a single-arm remote clinical trial examining the validity of a novel PPG-based software algorithm for detecting AF. The proprietary Fitbit algorithm examines pulse waveform intervals during analyzable periods in which participants are sufficiently stationary. Fitbit consumers with compatible wrist-worn trackers or smartwatches were invited to participate. Enrollment began May 6, 2020 and as of October 1, 2020, 455,699 participants enrolled. Participants in whom an irregular heart rhythm was detected were invited to attend a telehealth visit and eligible participants were then mailed a one-week single lead electrocardiographic (ECG) patch monitor. The primary study objective is to assess the positive predictive value of an irregular heart rhythm detection for AF during the ECG patch monitor period. Additional objectives will examine the validity of irregular pulse tachograms during subsequent heart rhythm detections, self-reported AF diagnoses and treatments, and relations between irregular heart rhythm detections and AF episode duration and time spent in AF. CONCLUSIONS: The Fitbit Heart Study is a large-scale remote clinical trial comprising a unique software algorithm for detection of AF. The study results will provide critical insights into the use of consumer wearable technology for AF detection, and for characterizing the nature of AF episodes detected using consumer-based PPG technology.

Rivaroxaban versus warfarin in patients with atrial fibrillation enrolled in Latin America: Insights from ROCKET AF.

BACKGROUND: ROCKET AF demonstrated the efficacy and safety of rivaroxaban compared with warfarin for the prevention of stroke and systemic embolism (SE) in patients with atrial fibrillation (AF). We examined baseline characteristics and outcomes in patients enrolled in Latin America compared with the rest of the world (ROW). METHODS: ROCKET AF enrolled 14,264 patients from 45 countries. Of these, 1,878 (13.2%) were from 7 Latin American countries. The clinical characteristics and outcomes (adjusted by baseline characteristics) of these patients were compared with 12,293 patients from the ROW. Treatment outcomes of rivaroxaban compared with warfarin were also stratified by region. RESULTS: The annual rate of stroke/SE was similar in those from Latin American and ROW (P= .63), but all-cause and vascular death were significantly higher than in ROW (HR 1.40, 95% CI 1.20-1.64; HR 1.38, 95% CI 1.14-1.68; P< .001). Rates of major or nonmajor clinically relevant bleeding tended to be lower in Latin America (HR 0.89, 95% CI 0.80-1.0; P= .05). Rates of stroke and/or SE were similar with rivaroxaban and warfarin in patients from Latin America and ROW (HR 0.83, 95% CI 0.54-1.29 vs HR 0.89, 95% CI 0.75-1.07; interaction P= .77). CONCLUSIONS: Patients with AF in Latin America had similar rates of stroke and/or SE, higher rates of vascular death, and lower rates of bleeding compared with patients in the ROW. The effect of rivaroxaban compared with warfarin in Latin America was similar to the ROW. Further studies analyzing patient- and country-specific determinants of these regional differences in Latin America are warranted.

Cigarette Smoking and Risk Perceptions During the COVID-19 Pandemic Reported by Recently Hospitalized Participants in a Smoking Cessation Trial.

BACKGROUND: Cigarette smoking is a risk factor for severe COVID-19 disease. Understanding smokers' responses to the pandemic will help assess its public health impact and inform future public health and provider messages to smokers. OBJECTIVE: To assess risk perceptions and change in tobacco use among current and former smokers during the COVID-19 pandemic. DESIGN: Cross-sectional survey conducted in May-July 2020 (55% response rate) PARTICIPANTS: 694 current and former daily smokers (mean age 53, 40% male, 78% white) who had been hospitalized pre-COVID-19 and enrolled into a smoking cessation clinical trial at hospitals in Massachusetts, Pennsylvania, and Tennessee. MAIN MEASURES: Perceived risk of COVID-19 due to tobacco use; changes in tobacco consumption and interest in quitting tobacco use; self-reported quitting and relapse since January 2020. KEY RESULTS: 68% (95% CI, 65-72%) of respondents believed that smoking increases the risk of contracting COVID-19 or having a more severe case. In adjusted analyses, perceived risk was higher in Massachusetts where COVID-19 had already surged than in Pennsylvania and Tennessee which were pre-surge during survey administration (AOR 1.56, 95% CI, 1.07-2.28). Higher perceived COVID-19 risk was associated with increased interest in quitting smoking (AOR 1.72, 95% CI 1.01-2.92). During the pandemic, 32% (95% CI, 27-37%) of smokers increased, 37% (95% CI, 33-42%) decreased, and 31% (95% CI, 26-35%) did not change their cigarette consumption. Increased smoking was associated with higher perceived stress (AOR 1.49, 95% CI 1.16-1.91). Overall, 11% (95% CI, 8-14%) of respondents who smoked in January 2020 (pre-COVID-19) had quit smoking at survey (mean, 6 months later) while 28% (95% CI, 22-34%) of former smokers relapsed. Higher perceived COVID-19 risk was associated with higher odds of quitting and lower odds of relapse. CONCLUSIONS: Most smokers believed that smoking increased COVID-19 risk. Smokers' responses to the pandemic varied, with increased smoking related to stress and increased quitting associated with perceived COVID-19 vulnerability.

Profile of patients diagnosed with acute venous thromboembolism in routine practice according to age and renal function: RE-COVERY DVT/PE study.

In randomized clinical trials (RCTs) of nonvitamin K antagonist oral anticoagulants (NOACs) for acute venous thromboembolism (VTE), ~ 12-13% of patients were elderly and ~ 26% had mild-to-moderate renal impairment. Observational studies are not restricted by the selection and treatment criteria of RCTs. In this ancillary analysis of the RE-COVERY DVT/PE global observational study, we aimed to describe patient characteristics, comorbidities, and anticoagulant therapy for subgroups of age (< or ≥ 75 years) and renal impairment (creatinine clearance [CrCl; estimated with Cockcroft-Gault formula] < 30 [severe], 30 to < 50 [moderate], 50 to < 80 [mild], ≥ 80 [normal] mL/min). Of 6095 eligible patients, 25.3% were aged ≥ 75 years; 38.2% (1605/4203 with CrCl values) had mild-to-moderate renal impairment. Comorbidities were more common in older patients (73.9% aged ≥ 75 vs. 58.1% < 75 years) and in those with mild or moderate versus no renal impairment (75.9%, 80.9%, and 59.3%, respectively). At hospital discharge or 14 days after diagnosis (whichever was later), most patients (53.7% and 55.1%, respectively) in both age groups received NOACs; 20.8% and 23.4%, respectively, received vitamin K antagonists, 19.0% and 21.8% parenteral therapy, 2.3% and 3.8% other anticoagulant treatments. Use of NOACs decreased with worsening renal impairment (none 58.5%, moderate 49.6%, severe 25.7%) and, in younger versus older patients with moderate renal impairment (33.1% vs. 56.1%). In routine practice, there are more elderly and renally impaired patients with VTE than represented in RCTs. Decreasing renal function, but not older age, was associated with less NOAC use. Clinical Trial Registration: http://www.clinicaltrials.gov . Unique identifier: NCT02596230. Decreasing renal function, particularly in the subgroup with CrCl < 30 mL/min, but not older age, was associated with less use of nonvitamin K antagonist oral anticoagulants (NOACs). Nevertheless, more than half of the older patients with moderate renal impairment received a NOAC as their oral anticoagulant.

Risk of major cardiovascular and neurologic events with obstructive sleep apnea among patients with atrial fibrillation.

BACKGROUND: Obstructive sleep apnea (OSA) is a known risk factor for atrial fibrillation (AF). However, it remains unclear whether OSA is independently associated with worse cardiovascular and neurological outcomes in patients with AF. METHODS: We used the ORBIT-AF I and ORBIT-AF II to conduct a retrospective cohort study of 22,760 patients with AF with and without OSA. Adjusted multivariable Cox proportional hazards models was used to determine whether OSA was associated with increased risk for major adverse cardiac and neurologic events (MACNEs) (cardiovascular death, myocardial infarction, stroke/transient ischemic attack/non-central nervous system embolism (stroke/SE), and new-onset heart failure], combined and individually. RESULTS: A total of 4,045 (17.8%) patients had OSA at baseline. Median follow-up time was 1.5 (interquartile range: 1-2.2) years, and 1,895 patients experienced a MACNE. OSA patients were younger (median [interquartile range] 68 [61-75] years vs 74 [66-81] years), were more likely male (70.7% vs 55.3%), and had increased body mass index (median 34.6 kg/m2 [29.8-40.2] vs 28.7 kg/m2 [25.2-33.0]). Those with OSA had a higher prevalence of concomitant comorbidities such as diabetes, chronic obstructive pulmonary disease, and heart failure. OSA patients had higher use of antithrombotic therapy. After adjustment, the presence of OSA was significantly associated with MACNE (hazard ratio: 1.16 [95% CI: 1.03-1.31], P = .011). OSA was also an independent risk factor for stroke/SE beyond the CHA2DS2-VASc risk factors (HR: 1.38 [95% CI 1.12-1.70], P = .003) but not cardiovascular death, myocardial infarction, new-onset heart failure, or major bleeding. CONCLUSIONS: Among patients with AF, OSA is an independent risk factor for MACNE and, more specifically, stroke/SE.

Patterns of amiodarone use and outcomes in clinical practice for atrial fibrillation.

BACKGROUND: Amiodarone is the most effective antiarrhythmic drug (AAD) for atrial fibrillation (AF), but it has a high incidence of adverse effects. METHODS: Using the ORBIT AF registry, patients with AF on amiodarone at enrollment, prescribed amiodarone during follow-up, or never on amiodarone were analyzed for the proportion treated with a guideline-based indication for amiodarone, the variability in amiodarone use across sites, and the outcomes (mortality, hospitalization, and stroke) among patients treated with amiodarone. Hierarchical logistic regression modeling with site-specific random intercepts compared rates of amiodarone use across 170 sites. A logistic regression model for propensity to receive amiodarone created a propensity-matched cohort. Cox proportional hazards modeling, stratified by matched pairs evaluated the association between amiodarone and outcomes. RESULTS: Among 6,987 AF patients, 867 (12%) were on amiodarone at baseline and 451 (6%) started on incident amiodarone during the 3-year follow-up. Use of amiodarone varied among sites from 3% in the lowest tertile to 21% in the highest (p<0.0001). Among those treated, 32% had documented contraindications to other AADs or had failed another AAD in the past. Mortality, cardiovascular hospitalization, and stroke were similar among matched patients on and not on amiodarone at baseline, while incident amiodarone use in matched patients was associated with higher all-cause mortality (adjusted HR 2.06, 95% CI 1.35-3.16). CONCLUSIONS: Use of amiodarone among AF patients in community practice is highly variable. More than 2 out of 3 patients treated with amiodarone appeared to be eligible for a different AAD.

Guideline-directed therapies for comorbidities and clinical outcomes among individuals with atrial fibrillation.

BACKGROUND: Comorbidities are common in patients with atrial fibrillation (AF) and affect prognosis, yet are often undertreated. However, contemporary rates of use of guideline-directed therapies (GDT) for non-AF comorbidities and their association with outcomes are not well described. METHODS: We used the Outcomes Registry for Better Informed Treatment of AF (ORBIT-AF) to test the association between GDT for non-AF comorbidities and major adverse cardiac or neurovascular events (MACNE; cardiovascular death, myocardial infarction, stroke/thromboembolism, or new-onset heart failure), all-cause mortality, new-onset heart failure, and AF progression. Adjustment was performed using Cox proportional hazards models and logistic regression. RESULTS: Only 6,782 (33%) of the 20,434 patients eligible for 1 or more GDT for non-AF comorbidities received all indicated therapies. Use of all comorbidity-specific GDT was highest for patients with hyperlipidemia (75.6%) and lowest for those with diabetes mellitus (43.1%). Use of "all eligible" GDT was associated with a nonsignificant trend toward lower rates of MACNE (HR 0.90 [0.79-1.02]) and all-cause mortality (HR 0.90 [0.80-1.01]). Use of GDT for heart failure was associated with a lower risk of all-cause mortality (HR 0.77 [0.67-0.89]), and treatment of obstructive sleep apnea was associated with a lower risk of AF progression (OR 0.75 [0.62-0.90]). CONCLUSIONS: In AF patients, there is underuse of GDT for non-AF comorbidities. The association between GDT use and outcomes was strongest in heart failure and obstructive sleep apnea patients where use of GDT was associated with lower mortality and less AF progression.