Clinical Outcomes in Older Patients with Atrial Fibrillation: Insights from the GARFIELD-AF Registry.

BACKGROUND: Oral anticoagulants (OAC) are underutilized in older patients with atrial fibrillation, despite proven clinical benefits. Our objective was to investigate baseline characteristics, treatment patterns, and impact of anticoagulation upon clinical outcomes with respect to age. METHODS: Adults with newly diagnosed atrial fibrillation were recruited into the prospective observational registry, GARFIELD-AF, and followed up for 24 months. Adjusted hazard ratios (HR) were obtained via Cox proportional-hazards models with applied weights, to quantify the association of age with clinical outcomes. Comparative effectiveness of OAC vs No OAC and non-vitamin K oral anticoagulants (NOAC) vs vitamin K antagonists (VKA) were assessed using a propensity score with an overlap weighting scheme. RESULTS: Of 52,018 patients, 32.6% were 65-74 years of age, 29.3% were 75-84 years, and 7.9% were ≥85 years. OAC treatment was associated with a numerical reduction in all-cause mortality among those aged 65-74 years (HR; 95% confidence interval) (0.86; 0.69-1.06) and aged 75-84 years (0.89; 0.75-1.05) and a significant reduction in patients ≥85 years (0.77; 0.63-0.95) vs no OAC. Similarly, OACs were associated with a decrease in stroke: 65-74 (0.51; 0.35-0.76) and ≥85 years (0.58; 0.34-0.99) and a numerical decrease in 75-84 years (0.84; 0.59-1.18). No increase in major bleeding was observed in patients aged ≥85 treated with OACs. Compared with VKA, NOACs were associated with a significant reduction in all-cause mortality in patients aged <65 and 65-74, with numerical reductions in those aged 75-84 and ≥85 years. CONCLUSIONS: Older patients using OACs saw lower all-cause mortality and stroke risk; NOACs had less mortality and major bleeding compared with VKAs.

Country and health expenditure are major predictors of withholding anticoagulation in atrial fibrillation patients at high risk of stroke.

BACKGROUND: Guidelines for patients with atrial fibrillation (AF) at high thromboembolic risk recommend oral anticoagulants (OACs) for preventing stroke and systemic embolism (SE). The reasons for guideline non-adherence are still unclear. AIM: The aim is to identify clinical, demographic and non-patient characteristics associated with withholding OAC in patients with AF at high stroke risk. METHODS: Patients in the Global Anticoagulant Registry in the FIELD-AF, newly diagnosed with AF between March 2010 and August 2016, and with CHA2DS2-VASc Score≥2 (excluding sex), were grouped by OAC treatment at enrolment. Factors associated with OAC non-use were analysed by multivariable logistic regression. RESULTS: Of 40 416 eligible patients, 12 126 (30.0%) did not receive OACs at baseline. Globally, OAC prescription increased over time, from 60.4% in 2010-2011 to 74.7% in 2015-2016. Country of enrolment was the major predictor for OAC withholding (χ2-df=2576). Clinical predictors of OAC non-use included type of AF (χ2-df=404), history of bleeding (χ2-df=263) and vascular disease (χ2-df=99). OACs were used most frequently around the age of 75 years and decreasingly with younger as well as older age beyond 75 years (χ2-df=148). Non-cardiologists (χ2-df=201) and emergency room physicians (χ2-df=14) were less likely to prescribe OACs. OAC prescription correlated positively with country health expenditure. CONCLUSIONS: Approximately one out of three AF patients did not receive OAC, while eligible according to the guidelines. Country of enrolment was the major determinant of anticoagulation strategy, while higher country health expenditure was associated with lower likelihood of withholding anticoagulation.

Rhythm versus rate control in patients with newly diagnosed atrial fibrillation - Observations from the GARFIELD-AF registry.

Background: Investigate real-world outcomes of early rhythm versus rate control in patients with recent onset atrial fibrillation. Methods: The Global Anticoagulant Registry in the FIELD-AF (GARFIELD-AF) is an international multi-centre, non-interventional prospective registry of newly diagnosed (≤6 weeks' duration) atrial fibrillation patients at risk for stroke. Patients were stratified according to treatment initiated at baseline (≤48 days post enrolment), and outcome risks evaluated by overlap propensity weighted Cox proportional-hazards models. Results: Of 45,382 non-permanent atrial fibrillation patients, 23,858 (52.6 %) received rhythm control and 21,524 (47.4 %) rate control. Rhythm-controlled patients had lower median age (68.0 [Q1;Q3: 60.0;76.0] versus 73.0 [65.0;79.0]), fewer histories of stroke/transient ischemic attack/systemic embolism (9.4 % versus 13.0 %), and lower expected probabilities of death (median GARFIELD-AF death score 4.0 [2.3;7.5] versus 5.1 [2.8;9.2]). The two groups had the same median CHA2DS2-VASc scores (3.0 [2.0;4.0]) and similar proportions of anticoagulated patients (rhythm control: 66.0 %, rate control: 65.5 %). The propensity-score-weighted hazard ratios of rhythm vs rate control (reference) were 0.85 (95 % CI: 0.79-0.92, p-value < 0.0001) for all-cause mortality, 0.84 (0.72-0.97, p-value 0.020) for non-haemorrhagic stroke/systemic embolism and 0.90 (0.78-1.04, p-value 0.164) for major bleeding. Conclusion: Rhythm control strategy was initiated in about half of the patients with newly diagnosed non-valvular non-permanent atrial fibrillation. After balancing confounders, significantly lower risks of all-cause mortality and non-haemorrhagic stroke were observed in patients who received early rhythm control.

Outcomes of Oral Anticoagulation in Atrial Fibrillation Patients With or Without Comorbid Vascular Disease: Insights From the GARFIELD-AF Registry.

BACKGROUND: Many patients with atrial fibrillation suffer from comorbid vascular disease. The comparative efficacy and safety of different types of oral anticoagulation (OAC) in this patient group have not been widely studied. METHODS: Adults with newly diagnosed atrial fibrillation were recruited into the prospective observational registry, GARFIELD-AF, and followed for 24 months. Associations of vascular disease with clinical outcomes were analyzed using adjusted hazard ratios (HR) obtained via Cox proportional-hazard modeling. Outcomes of OAC vs no OAC, and of non-vitamin K antagonist OAC (NOAC) vs vitamin K antagonist (VKA) treatment, were compared by overlap propensity-weighted Cox proportional-hazard models. RESULTS: Of 51,574 atrial fibrillation patients, 25.9% had vascular disease. Among eligible atrial fibrillation patients, those with vascular disease received OAC less frequently than those without (63% vs 73%). Over 2-year follow-up, patients with vascular disease showed a higher risk of all-cause mortality (HR 1.30; 95% confidence interval [CI], 1.16-1.47) and cardiovascular mortality (HR 1.59; 95% CI, 1.28-1.97). OAC was associated with a significant decrease in all-cause mortality and non-hemorrhagic stroke, and increased risk of major bleeding in non-vascular disease. In vascular disease, similar but non-significant trends existed for stroke and major bleeding. A significantly lower risk of all-cause mortality (HR 0.74; 95% CI, 0.61-0.90) and major bleeding (HR 0.45; 95% CI, 0.29-0.70) was observed in vascular disease patients treated with NOACs, compared with VKAs. CONCLUSIONS: Atrial fibrillation patients with a history of vascular disease have worse long-term outcomes than those without. The association of NOACs vs VKA with clinical outcomes was more evident in atrial fibrillation patients with vascular disease.

Enoxaparin for symptomatic COVID-19 managed in the ambulatory setting: An individual patient level analysis of the OVID and ETHIC trials.

BACKGROUND: Antithrombotic treatment may improve the disease course in non-critically ill, symptomatic COVID-19 outpatients. METHODS: We performed an individual patient-level analysis of the OVID and ETHIC randomized controlled trials, which compared enoxaparin thromboprophylaxis for either 14 (OVID) or 21 days (ETHIC) vs. no thromboprophylaxis for outpatients with symptomatic COVID-19 and at least one additional risk factor. The primary efficacy outcome included all-cause hospitalization and all-cause death within 30 days from randomization. Both studies were prematurely stopped for futility. Secondary efficacy outcomes were major symptomatic venous thromboembolic events, arterial cardiovascular events, or their composite occurring within 30 days from randomization. The same outcomes were assessed over a 90-day follow-up. The primary safety outcome was major bleeding (ISTH criteria). RESULTS: A total of 691 patients were randomized: 339 to receive enoxaparin and 352 to the control group. Over 30-day follow-up, the primary efficacy outcome occurred in 6.0 % of patients in the enoxaparin group vs. 5.8 % of controls for a risk ratio (RR) of 1.05 (95%CI 0.57-1.92). The incidence of major symptomatic venous thromboembolic events and arterial cardiovascular events was 0.9 % vs. 1.8 %, respectively (RR 0.52; 95%CI 0.13-2.06). Most cardiovascular thromboembolic events were represented by symptomatic venous thromboembolic events, occurring in 0.6 % vs. 1.5 % of patients, respectively. A similar distribution of outcomes between the treatment groups was observed over 90 days. No major bleeding occurred in the enoxaparin group vs. one (0.3 %) in the control group. CONCLUSIONS: We found no evidence for the clinical benefit of early administration of enoxaparin thromboprophylaxis in outpatients with symptomatic COVID-19. These results should be interpreted taking into consideration the relatively low occurrence of events.

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.

Predictors of intracranial hemorrhage in patients with atrial fibrillation treated with oral anticoagulants: Insights from the GARFIELD-AF and ORBIT-AF registries.

BACKGROUND: An unmet need exists to reliably predict the risk of intracranial hemorrhage (ICH) in patients with atrial fibrillation (AF) treated with oral anticoagulants (OACs). HYPOTHESIS: An externally validated model improves ICH risk stratification. METHODS: Independent factors associated with ICH were identified by Cox proportional hazard modeling, using pooled data from the GARFIELD-AF (Global Anticoagulant Registry in the FIELD-Atrial Fibrillation) and ORBIT-AF (Outcomes Registry for Better Informed Treatment of Atrial Fibrillation) registries. A predictive model was developed and validated by bootstrap sampling and by independent data from the Danish National Patient Register. RESULTS: In the combined training data set, 284 of 53 878 anticoagulated patients had ICH over a 2-year period (0.31 per 100 person-years; 95% confidence interval [CI]: 0.28-0.35). Independent predictors of ICH included: older age, prior stroke or transient ischemic attack, concomitant antiplatelet (AP) use, and moderate-to-severe chronic kidney disease (CKD). Vitamin K antagonists (VKAs) were associated with a significantly higher risk of ICH compared with non-VKA oral anticoagulants (NOACs) (adjusted hazard ratio: 1.61; 95% CI: 1.25-2.08; p = .0002). The ability of the model to discriminate individuals in the training set with and without ICH was fair (optimism-corrected C-statistic: 0.68; 95% CI: 0.65-0.71) and outperformed three previously published methods. Calibration between predicted and observed ICH probabilities was good in both training and validation data sets. CONCLUSIONS: Age, prior ischemic events, concomitant AP therapy, and CKD were important risk factors for ICH in anticoagulated AF patients. Moreover, ICH was more frequent in patients receiving VKA compared to NOAC. The new validated model is a step toward mitigating this potentially lethal complication.

Oral anticoagulation across diabetic subtypes in patients with newly diagnosed atrial fibrillation: A report from the GARFIELD-AF registry.

AIMS: This study aims to describe both management and prognosis of patients with diabetes mellitus (DM) and newly diagnosed atrial fibrillation (AF), overall as well as by antidiabetic treatment, and to assess the influence of oral anticoagulation (OAC) on outcomes by DM status. METHODS: The study population comprised 52 010 newly diagnosed patients with AF, 11 542 DM and 40 468 non-DM, enrolled in the GARFIELD-AF registry. Follow-up was truncated at 2 years after enrolment. Comparative effectiveness of OAC versus no OAC was assessed by DM status using a propensity score overlap weighting scheme and weights were applied to Cox models. RESULTS: Patients with DM [39.3% oral antidiabetic drug (OAD), 13.4% insulin ± OAD, 47.2% on no antidiabetic drug] had higher risk profile, OAC use, and rates of clinical outcomes compared with patients without DM. OAC use was associated in patients without DM and patients with DM with lower risk of all-cause mortality [hazard ratio 0.75 (0.69-0.83), 0.74 (0.64-0.86), respectively] and stroke/systemic embolism (SE) [0.69 (0.58-0.83), 0.70 (0.53-0.93), respectively]. The risk of major bleeding with OAC was similarly increased in patients without DM and those with DM [1.40 (1.14-1.71), 1.37 (0.99-1.89), respectively]. Patients with insulin-requiring DM had a higher risk of all-cause mortality and stroke/SE [1.91 (1.63-2.24)], [1.57 (1.06-2.35), respectively] compared with patients without DM, and experienced significant risk reductions of all-cause mortality and stroke/SE with OAC [0.73 (0.53-0.99); 0.50 (0.26-0.97), respectively]. CONCLUSIONS: In both patients with DM and patients without DM with AF, OAC was associated with lower risk of all-cause mortality and stroke/SE. Patients with insulin-requiring DM derived significant benefit from OAC.

Guideline-directed medical therapies for comorbidities among patients with atrial fibrillation: results from GARFIELD-AF.

Aims: This study aimed to identify relationships in recently diagnosed atrial fibrillation (AF) patients with respect to anticoagulation status, use of guideline-directed medical therapy (GDMT) for comorbid cardiovascular conditions (co-GDMT), and clinical outcomes. The Global Anticoagulant Registry in the FIELD (GARFIELD)-AF is a prospective, international registry of patients with recently diagnosed non-valvular AF at risk of stroke (NCT01090362). Methods and results: Guideline-directed medical therapy was defined according to the European Society of Cardiology guidelines. This study explored co-GDMT use in patients enrolled in GARFIELD-AF (March 2013-August 2016) with CHA2DS2-VASc ≥ 2 (excluding sex) and ≥1 of five comorbidities-coronary artery disease, diabetes mellitus, heart failure, hypertension, and peripheral vascular disease (n = 23 165). Association between co-GDMT and outcome events was evaluated with Cox proportional hazards models, with stratification by all possible combinations of the five comorbidities. Most patients (73.8%) received oral anticoagulants (OACs) as recommended; 15.0% received no recommended co-GDMT, 40.4% received some, and 44.5% received all co-GDMT. At 2 years, comprehensive co-GDMT was associated with a lower risk of all-cause mortality [hazard ratio (HR) 0.89 (0.81-0.99)] and non-cardiovascular mortality [HR 0.85 (0.73-0.99)] compared with inadequate/no GDMT, but cardiovascular mortality was not significantly reduced. Treatment with OACs was beneficial for all-cause mortality and non-cardiovascular mortality, irrespective of co-GDMT use; only in patients receiving all co-GDMT was OAC associated with a lower risk of non-haemorrhagic stroke/systemic embolism. Conclusion: In this large prospective, international registry on AF, comprehensive co-GDMT was associated with a lower risk of mortality in patients with AF and CHA2DS2-VASc ≥ 2 (excluding sex); OAC therapy was associated with reduced all-cause mortality and non-cardiovascular mortality, irrespective of co-GDMT use. Clinical Trial Registration: Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362.

Determinants and clinical outcomes of patients who refused anticoagulation: findings from the global GARFIELD-AF registry.

OBJECTIVE: There is a substantial incidence of stroke in patients with atrial fibrillation (AF) not receiving anticoagulation. The reasons for not receiving anticoagulation are generally attributed to clinician's choice, however, a proportion of AF patients refuse anticoagulation. The aim of our study was to investigate factors associated with patient refusal of anticoagulation and the clinical outcomes in these patients. METHODS: Our study population comprised patients in the Global Anticoagulant Registry in the FIELD (GARFIELD-AF) registry with CHA2DS2-VASc≥2. A logistic regression was developed with predictors of patient anticoagulation refusal identified by least absolute shrinkage and selection operator methodology. Patient demographics, medical and cardiovascular history, lifestyle factors, vital signs (body mass index, pulse, systolic and diastolic blood pressure), type of AF and care setting at diagnosis were considered as potential predictors. We also investigated 2-year outcomes of non-haemorrhagic stroke/systemic embolism (SE), major bleeding and all-cause mortality in patients who refused versus patients who received and patients who did not receive anticoagulation for other reasons. RESULTS: Out of 43 154 AF patients, who were at high risk of stroke, 13 283 (30.8%) did not receive anticoagulation at baseline. The reason for not receiving anticoagulation was unavailable for 38.7% (5146/13 283); of the patients with a known reason for not receiving anticoagulation, 12.5% (1014/8137) refused anticoagulation. Diagnosis in primary care/general practitioner, Asian ethnicity and presence of vascular disease were strongly associated with a higher risk of patient refusal of anticoagulation. Patient refusal of anticoagulation was associated with a higher risk of non-haemorrhagic stroke/SE (adjusted HR (aHR) 1.16 (95% CI 0.77 to 1.76)) but lower all-cause mortality (aHR 0.59 (95% CI 0.43 to 0.80)) compared with patients who received anticoagulation. The GARFIELD-AF mortality score corroborated this result. CONCLUSION: The data suggest patient refusal of anticoagulation is a missed opportunity to prevent AF-related stroke. Further research is required to understand the patient profile and mortality outcome of patients who refuse anticoagulation.

Healthcare Resource Utilization in Patients with Newly Diagnosed Atrial Fibrillation: A Global Analysis from the GARFIELD-AF Registry.

The management of atrial fibrillation (AF), the most common sustained arrhythmia, impacts healthcare resource utilization (HCRU). This study aims to estimate global resource use in AF patients, using the GARFIELD-AF registry. A prospective cohort study was conducted to characterize HCRU in AF patients enrolled in sequential cohorts from 2012 to 2016 in 35 countries. Components of HCRU studied were hospital admissions, outpatient care visits, and diagnostic and interventional procedures occurring during follow-up. AF-related HCRU was reported as the percentage of patients demonstrating at least one event and was quantified as rate-per-patient-per-year (PPPY) over time. A total of 49,574 patients was analyzed, having an overall median follow-up of 719 days. Almost all patients (99.5%) had at least one outpatient care visit, while hospital admissions were the second most frequent medical contact, with similar proportions in North America (37.5%) and Europe (37.2%), and slightly higher in the other GARFIELD-AF countries (42.0%; namely Australia, Egypt, and South Africa). Asia and Latin America showed lower percentages of hospitalizations, outpatient care visits, and diagnostic and interventional procedures. Analyses of GARFIELD-AF highlighted the vast AF-related HCRU, underlying significant geographical differences in the type, quantity, and frequency of AF-related HCRU. These differences were likely attributable to health service availability and differing models of care.

GARFIELD-AF: risk profiles, treatment patterns and 2-year outcomes in patients with atrial fibrillation in Germany, Austria and Switzerland (DACH) compared to 32 countries in other regions worldwide.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is a worldwide non-interventional study of stroke prevention in patients with non-valvular AF. METHODS AND RESULTS: 52,080 patients with newly diagnosed AF were prospectively enrolled from 2010 to 2016. 4121 (7.9%) of these patients were recruited in DACH [Germany (n = 3567), Austria (n = 465) and Switzerland (n = 89) combined], and 47,959 patients were from 32 countries in other regions worldwide (ORW). Hypertension was most prevalent in DACH and ORW (85.3% and 75.6%, respectively). Diabetes, hypercholesterolaemia, carotid occlusive disease and vascular disease were more prevalent in DACH patients vs ORW (27.6%, 49.4%, 5.8% and 29.0% vs 21.7%, 40.9%, 2.8% and 24.5%). The use of non-vitamin K antagonist oral anticoagulants (NOACs) increased more in DACH over time. Management of vitamin K antagonists was suboptimal in DACH and ORW (time in therapeutic range of INR ≥ 65% in 44.6% and 44.4% of patients or ≥ 70% in 36.9% and 36.0% of patients, respectively). Adjusted rates of cardiovascular mortality and MI/ACS were higher in DACH while non-haemorrhagic stroke/systemic embolism was lower after 2-year follow-up. CONCLUSIONS: Similarities and dissimilarities in AF management and clinical outcomes are seen in DACH and ORW. The increased use of NOAC was associated with a mismatch of risk-adapted anticoagulation (over-and-undertreatment) in DACH. Suboptimal control of INR requires educational activities in both regional groups. Higher rates of cardiovascular death in DACH may reflect the higher risk profile of these patients and lower rates of non-haemorrhagic stroke could be associated with increased NOAC use.

Thromboprophylactic low-molecular-weight heparin versus standard of care in unvaccinated, at-risk outpatients with COVID-19 (ETHIC): an open-label, multicentre, randomised, controlled, phase 3b trial.

BACKGROUND: COVID-19 is associated with inflammation and an increased risk of thromboembolic complications. Prophylactic doses of low-molecular-weight heparin have been used in hospitalised and non-critically ill patients with COVID-19. We aimed to evaluate the efficacy and safety of prophylactic low-molecular-weight heparin (enoxaparin) versus standard of care (no enoxaparin) in at-risk outpatients with COVID-19. METHODS: This open-label, multicentre, randomised, controlled, phase 3b trial (ETHIC) was done at 15 centres in six countries (Belgium, Brazil, India, South Africa, Spain, and the UK). We consecutively enrolled participants aged at least 30 years who had not received a COVID-19 vaccine and had symptomatic, confirmed COVID-19 in the outpatient setting plus at least one risk factor for severe disease. Within 9 days of symptom onset and by use of a web-based random block design (block size either 2 or 4), eligible participants were randomly assigned (1:1) to receive either subcutaneous enoxaparin for 21 days (40 mg once daily if they weighed <100 kg and 40 mg twice daily if they weighed ≥100 kg) or standard of care (without enoxaparin). The primary efficacy endpoint was the composite of all-cause hospitalisation and all-cause mortality at 21 days after randomisation and, in our main analysis, was analysed in the intention-to-treat population, which comprised all patients who were randomly assigned. Safety was also analysed in the intention-to-treat population for our main analysis. This trial is registered with ClinicalTrials.gov, NCT04492254, and is complete. FINDINGS: Following the advice of the Data and Safety Monitoring Board, this study was terminated early due to slow enrolment and a lower-than-expected event rate. Between Oct 27, 2020, and Nov 8, 2021, 230 patients with COVID-19 were assessed for eligibility, of whom 219 were enrolled and randomly assigned to receive standard of care (n=114) or enoxaparin (n=105). 96 (44%) patients were women, 122 (56%) were men, and one patient had missing sex data. 141 (65%) of 218 participants with data on race and ethnicity were White, 60 (28%) were Asian, and 16 (7%) were Black, mixed race, or Arab or Middle Eastern. Median follow-up in both groups was 21 days (IQR 21-21). There was no difference in the composite of all-cause mortality and hospitalisation at 21 days between the enoxaparin group (12 [11%] of 105 patients) and the standard-of-care group (12 [11%] of 114 patients; unadjusted hazard ratio 1·09 [95% CI 0·49-2·43]; log-rank p=0·83). At 21 days, two (2%) of 105 patients in the enoxaparin group (one minor bleed and one bleed of unknown severity) and one (1%) of 114 patients in the standard-of-care group (major abnormal uterine bleeding) had a bleeding event. 22 (21%) patients in the enoxaparin group and 13 (11%) patients in the standard-of-care group had adverse events. The most common adverse event in both groups was COVID-19-related pneumonia (six [6%] patients in the enoxaparin group and five [4%] patients in the standard-of-care group). One patient in the enoxaparin group died and their cause of death was unknown. INTERPRETATION: The ETHIC trial results suggest that prophylaxis with low-molecular-weight heparin had no benefit for at-risk outpatients with COVID-19. Although the trial was terminated early, our data, combined with data from similar studies, provide further insights to inform international guidelines and influence clinical practice. FUNDING: The Thrombosis Research Institute and Sanofi UK.

Two-year outcomes of UK patients newly diagnosed with atrial fibrillation: findings from the prospective observational cohort study GARFIELD-AF.

BACKGROUND: The outcomes of patients newly diagnosed with atrial fibrillation (AF) following the introduction of direct-acting oral anticoagulants are not well known. AIM: To determine the 2-year outcomes of patients newly diagnosed with AF, and the effectiveness of oral anticoagulants in everyday practice. DESIGN AND SETTING: This was a prospective observational cohort study in UK primary care. METHOD: In total, 3574 patients aged ≥18 years with a new AF diagnosis were enrolled. A propensity score was applied using an overlap weighting scheme to obtain unbiased estimates of the treatment effect of anticoagulation versus no anticoagulation on the occurrence of death, non-haemorrhagic stroke/systemic embolism, and major bleeding within 2 years of diagnosis. RESULTS: Overall, 65.8% received anticoagulant therapy, 20.8% received an antiplatelet only, and 13.4% received neither. During the study period, the overall incidence rates of all-cause mortality, non-haemorrhagic stroke/systemic embolism, and major bleeding were 4.15 (95% confidence interval [CI] = 3.69 to 4.65), 1.45 (95% CI = 1.19 to 1.77), and 1.21 (95% CI = 0.97 to 1.50) per 100 person-years, respectively. Anticoagulation treatment compared with no anticoagulation treatment was associated with significantly lower all-cause mortality adjusted hazard ratio (aHR) 0.70 (95% CI = 0.53 to 0.93), significantly lower risk of non-haemorrhagic stroke/systemic embolism (aHR 0.39, 95% CI = 0.24 to 0.62), and a non-significant higher risk of major bleeding (aHR 1.31, 95% CI = 0.77 to 2.24). CONCLUSION: The data support a benefit of anticoagulation in reducing stroke and death, without an increased risk of a major bleed in patients with new-onset AF. Anticoagulation treatment in patients at high risk of stroke who are not receiving anticoagulation may further improve outcomes.

Validating risk models versus age alone for atrial fibrillation in a young Dutch population cohort: should atrial fibrillation risk prediction be expanded to younger community members?

BACKGROUND: Advancing age is the primary selection criterion for community screening for atrial fibrillation (AF), with selection often restricted to those aged ≥65 years. If multivariable models were shown to have considerable additional value over age alone in predicting AF risk among younger individuals, AF screening could be expanded to patients with lower age, but with high AF risk as per a validated risk model. METHODS: We validated risk models CHARGE-AF (Cohorts for Heart and Aging Research in Genomic Epidemiology model for AF) and FHS-AF (Framingham Heart Study model for AF), and risk scores CHA2DS2-VASc and CHA2DS2-VA, and presented their predictive abilities for 5-year and 10-year AF risk versus that of age alone in a young Dutch population cohort (PREVEND) free from AF at baseline. We assessed discrimination by the C-statistic and calibration by the calibration plot and stratified Kaplan-Meier plot using survey-weighted Cox models. RESULTS: During 5-year and 10-year follow-up there were n=98 (2.46/1000 person-years) and n=249 (3.29/1000 person-years) new AF cases, respectively, among 8265 participants with mean age 49±13 years. CHARGE-AF and FHS-AF both showed good discrimination for 5-year and 10-year AF (C-statistic range 0.83-0.86) with accurate calibration for 5-year AF, but overestimation of 10-year AF risk in highest-risk individuals. CHA2DS2-VASc and CHA2DS2-VA relatively underperformed. Age alone showed similar discrimination to that of CHARGE-AF and FHS-AF both in the overall, young PREVEND cohort and in subgroups for lower age and lower stroke risk. CONCLUSION: Multivariable models accurately discriminate for 5-year and 10-year AF risk among young European community-dwelling individuals. However, their additional discriminatory value over age alone was limited. Selection strategies for primary AF screening using multivariable models should not be expanded to younger individuals.

Do baseline characteristics and treatments account for geographical disparities in the outcomes of patients with newly diagnosed atrial fibrillation? The prospective GARFIELD-AF registry.

OBJECTIVE: In patients with newly diagnosed atrial fibrillation (AF), do baseline risk factors and stroke prevention strategies account for the geographically diverse outcomes. DESIGN: Global Anticoagulant Registry in the FIELD-Atrial Fibrillation is a prospective multinational non-interventional registry of patients with newly diagnosed AF (n=52 018 patients). SETTING: Investigator sites (n=1317) were representative of the care settings/locations in each of the 35 participating countries. Treatment decisions were all determined by the local responsible clinicians. PARTICIPANTS: The patients (18 years and over) with newly diagnosed AF had at least 1 investigator-determined stroke risk factor and patients were not required to meet specific thresholds of risk score for anticoagulant treatment. MAIN OUTCOMES AND MEASURES: Observed 1-year event rates and risk-standardised rates were derived. RESULTS: Rates of death, non-haemorrhagic stroke/systemic embolism and major bleeding varied more than three-to-four fold across countries even after adjustment for baseline factors and antithrombotic treatments. Rates of anticoagulation and antithrombotic treatment varied widely. Patients from countries with the highest rates of cardiovascular mortality and stroke were among the least likely to receive oral anticoagulants. Beyond anticoagulant treatment, variations in the treatment of comorbidities and lifestyle factors may have contributed to the variations in outcomes. Countries with the lowest healthcare Access and Quality indices (India, Ukraine, Argentina, Brazil) had the highest risk-standardised mortality. CONCLUSION: The variability in outcomes across countries for patients with newly diagnosed AF is not accounted for by baseline characteristics and antithrombotic treatments. Residual mortality rates were correlated with Healthcare Access and Quality indices. The findings suggest the management of patients with AF needs to not only address guideline indicated and sustained anticoagulation, but also the treatment of comorbidities and lifestyle factors. TRIAL REGISTRATION NUMBER: NCT01090362.

Universal Clinician Device for improving risk prediction and management of patients with atrial fibrillation: an assumed benefit analysis.

Aim: Atrial fibrillation (AF) management guidelines advise using risk tools to optimize AF treatment. This study aims to develop a dynamic and clinically applicable digital device to assess stroke and bleeding risk, and to facilitate outcome improvements in AF patients. The device will provide tailored treatment recommendations according to easily attainable individual patient data. Methods and Results: This Universal Clinician Device (UCD) was created using the GARFIELD-AF registry using a split sample approach. The GARFIELD-AF risk tool was adapted with two modifications. First, predictors with ≥1000 missing data points were separated, allowing expected risks estimation. Second, recommendations for modifiable risk factors and associated 2-year outcome estimates were incorporated. Outcomes of interest were all-cause mortality, non-haemorrhagic stroke/systemic embolism (SE), and major bleeding. All patients were randomized to a derivation (n = 34853) and validation cohort (n = 17165). In the derivation cohort, predictors were identified using least absolute shrinkage and selection operator regression. Cox models were fitted with the selected parameters. The UCD demonstrated superior predictive power compared with CHA2DS2VASc for all-cause mortality [0.75(0.75-0.76) vs. 0.71(0.70-0.72)] and non-haemorrhagic stroke/SE [0.68(0.66-0.70) vs. 0.65(0.63-0.67)], and with HAS-BLED for major bleeding [0.69(0.67-0.71) vs. 0.64(0.62-0.65)]. Universal Clinician Device recommendations reduced all-cause mortality (8.45-5.42%) and non-haemorrhagic stroke/SE (2.58-1.50%). Patients with concomitant diabetes and chronic kidney disease benefitted further, reducing mortality risk from 13.15% to 8.67%. One-third of patients with a CHA2DS2VASc score of >1 had the lowest risk of stroke. Conclusion: The UCD simultaneously predicts mortality, stroke, and bleeding risk in patients using easily attainable individual clinical data and guideline-based optimized treatment plans. Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier for GARFIELD-AF: NCT01090362.

GARFIELD-AF risk score for mortality, stroke, and bleeding within 2 years in patients with atrial fibrillation.

AIMS: To determine whether the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) integrated risk tool predicts mortality, non-haemorrhagic stroke/systemic embolism, and major bleeding for up to 2 years after new-onset AF and to assess how this risk tool performs compared with CHA2DS2-VASc and HAS-BLED. METHODS AND RESULTS: Potential predictors of events included demographic and clinical characteristics, choice of treatment, and lifestyle factors. A Cox proportional hazards model was identified for each outcome by least absolute shrinkage and selection operator methods. Indices were evaluated in comparison with CHA2DS2-VASc and HAS-BLED risk predictors. Models were validated internally and externally in ORBIT-AF and Danish nationwide registries. Among the 52 080 patients enrolled in GARFIELD-AF, 52 032 had follow-up data. The GARFIELD-AF risk tool outperformed CHA2DS2-VASc for all-cause mortality in all cohorts. The GARFIELD-AF risk score was superior to CHA2DS2-VASc for non-haemorrhagic stroke, and it outperformed HAS-BLED for major bleeding in internal validation and in the Danish AF cohort. In very low- to low-risk patients [CHA2DS2-VASc 0 or 1 (men) and 1 or 2 (women)], the GARFIELD-AF risk score offered strong discriminatory value for all the endpoints when compared to CHA2DS2-VASc and HAS-BLED. The GARFIELD-AF tool also included the effect of oral anticoagulation (OAC) therapy, thus allowing clinicians to compare the expected outcome of different anticoagulant treatment decisions [i.e. no OAC, non-vitamin K antagonist (VKA) oral anticoagulants, or VKAs]. CONCLUSIONS: The GARFIELD-AF risk tool outperformed CHA2DS2-VASc at predicting death and non-haemorrhagic stroke, and it outperformed HAS-BLED for major bleeding in overall as well as in very low- to low-risk group patients with AF. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier for GARFIELD-AF: NCT01090362, ORBIT-AF I: NCT01165710; ORBIT-AF II: NCT01701817.

The importance of the design of observational studies in comparative effectiveness research: Lessons from the GARFIELD-AF and ORBIT-AF registries.

Randomized controlled trials (RCTs) are considered the gold standard for estimating the effectiveness of a treatment. However, in many instances they are impractical to conduct because of time limitations, cost restrictions, or ethical reasons. As a consequence, non-randomized observational studies have an important role in comparative effectiveness and safety research since they can address issues that would not be possible using conventional RCT methodology. Observational studies can be strategically designed to reduce the risk of potential sources of bias by emulating the design principles of an equivalent but ideal randomized trial - the target trial - that would answer the research question of interest. In this article, we review some of the necessary components of observational studies required for valid causal inference within the framework of target trial emulation, so as to avoid common methodological pitfalls of study design. We discuss the assumptions of consistency, time-zero specification, exchangeability and positivity. To illustrate these concepts in a context where existing knowledge is well-established through clinical trials, we evaluate and compare the treatment effects of vitamin K antagonists (VKA) against no VKA (No VKA) on the treatment of atrial fibrillation from two real-world observational studies, namely the GARFIELD-AF and ORBIT-AF registries. Results are compared with those of published RCTs.