Abstract Background Oral anticoagulation (OAC), rather than aspirin, is recommended in patients with atrial fibrillation (AF) at moderate to high risk of stroke. Objectives This study sought to ...examine patient and practice-level factors associated with prescription of aspirin alone compared with OAC in AF patients at intermediate to high stroke risk in real-world cardiology practices. Methods The authors identified 2 cohorts of outpatients with AF and intermediate to high thromboembolic risk (CHADS2 score ≥2 and CHA2 DS2 -VASc ≥2) enrolled in the American College of Cardiology PINNACLE (Practice Innovation and Clinical Excellence) registry between 2008 and 2012. Using hierarchical modified Poisson regression models adjusted for patient and practice characteristics, the authors examined the prevalence and predictors of aspirin alone versus OAC prescription in AF patients at risk for stroke. Results Of 210,380 identified patients with CHADS2 score ≥2 on antithrombotic therapy, 80,371 (38.2%) were treated with aspirin alone, and 130,009 (61.8%) were treated with warfarin or non-vitamin K antagonist OACs. In the cohort of 294,642 patients with CHA2 DS2 -VASc ≥2, 118,398 (40.2%) were treated with aspirin alone, and 176,244 (59.8%) were treated with warfarin or non-vitamin K antagonist OACs. After multivariable adjustment, hypertension, dyslipidemia, coronary artery disease, prior myocardial infarction, unstable and stable angina, recent coronary artery bypass graft, and peripheral arterial disease were associated with prescription of aspirin only, whereas male sex, higher body mass index, prior stroke/transient ischemic attack, prior systemic embolism, and congestive heart failure were associated with more frequent prescription of OAC. Conclusions In a large, real-world cardiac outpatient population of AF patients with a moderate to high risk of stroke, more than 1 in 3 were treated with aspirin alone without OAC. Specific patient characteristics predicted prescription of aspirin therapy over OAC.
Background Dabigatran is a novel oral anti-coagulant (NOAC) that reduces risk of stroke in patients with non-valvular atrial fibrillation (NVAF). It does not require routine monitoring with ...laboratory testing which may have an adverse impact on adherence. We aimed to describe adherence to dabigatran in the first year after initiation and assess the association between non-adherence to dabigatran and clinical outcomes in a large integrated healthcare system. Methods We studied a national cohort of 5,376 patients with NVAF, initiated on dabigatran between October-2010 and September-2012 at all Veterans Affairs hospitals. Adherence to dabigatran was calculated as proportion of days covered (PDC) and association between PDC and outcomes was assessed using standard regression techniques. Results Mean age of the study cohort was 71.3 ± 9.7 years; 98.3% were men and mean CHADS2 score was 2.4 ± 1.2 (mean CHA2 DS2 VASc score 3.2 ± 1.4). Median PDC was 94% (IQR 76%-100%; mean PDC 84% ± 22%) over a median follow-up of 244 days (IQR 140-351). A total of 1,494 (27.8%) patients had a PDC <80% and were classified as non-adherent. After multivariable adjustment, lower adherence was associated with increased risk for combined all-cause mortality and stroke (HR 1.13, 95% CI 1.07–1.19 per 10% decrease in PDC). Adherence to dabigatran was not associated with non-fatal bleeding or myocardial infarction. Conclusions In the year after initiation, adherence to dabigatran for a majority of patients is very good. However, 28% of patients in our cohort had poor adherence. Furthermore, lower adherence to dabigatran was associated with increased adverse outcomes. Concerted efforts are needed to optimize adherence to NOACs.
Although extending the duration of ambulatory electrocardiographic monitoring beyond 24 to 48 hours can improve the detection of arrhythmias, lead-based (Holter) monitors might be limited by patient ...compliance and other factors. We, therefore, evaluated compliance, analyzable signal time, interval to arrhythmia detection, and diagnostic yield of the Zio Patch, a novel leadless, electrocardiographic monitoring device in 26,751 consecutive patients. The mean wear time was 7.6 ± 3.6 days, and the median analyzable time was 99% of the total wear time. Among the patients with detected arrhythmias (60.3% of all patients), 29.9% had their first arrhythmia and 51.1% had their first symptom-triggered arrhythmia occur after the initial 48-hour period. Compared with the first 48 hours of monitoring, the overall diagnostic yield was greater when data from the entire Zio Patch wear duration were included for any arrhythmia (62.2% vs 43.9%, p <0.0001) and for any symptomatic arrhythmia (9.7% vs 4.4%, p <0.0001). For paroxysmal atrial fibrillation (AF), the mean interval to the first detection of AF was inversely proportional to the total AF burden, with an increasing proportion occurring after 48 hours (11.2%, 10.5%, 20.8%, and 38.0% for an AF burden of 51% to 75%, 26% to 50%, 1% to 25%, and <1%, respectively). In conclusion, extended monitoring with the Zio Patch for ≤14 days is feasible, with high patient compliance, a high analyzable signal time, and an incremental diagnostic yield beyond 48 hours for all arrhythmia types. These findings could have significant implications for device selection, monitoring duration, and care pathways for arrhythmia evaluation and AF surveillance.
Background Although warfarin is indicated to prevent ischemic strokes in most patients with atrial fibrillation (AF), evidence supporting its use in hemodialysis patients is limited. Our aim was to ...examine outcomes after warfarin therapy initiation, relative to no warfarin use, following incident AF in a large cohort of hemodialysis patients who had comprehensive prescription drug coverage through Medicare Part D. Study Design Retrospective observational cohort study. Setting & Participants Patients in the US Renal Data System undergoing maintenance hemodialysis who had AF newly diagnosed in 2007 to 2011, with Medicare Part D coverage, who had no recorded history of warfarin use. Predictor Warfarin therapy initiation, identified by a filled prescription within 30 days of the AF event. Outcomes Death, ischemic stroke, hemorrhagic stroke, severe gastrointestinal bleeding, and composite outcomes. Measurements HRs estimated by applying Cox regression to an inverse probability of treatment and censoring-weighted cohort. Results Of 12,284 patients with newly diagnosed AF, 1,838 (15%) initiated warfarin therapy within 30 days; however, ∼70% discontinued its use within 1 year. In intention-to-treat analyses, warfarin use was marginally associated with a reduced risk of ischemic stroke (HR, 0.68; 95% CI, 0.47-0.99), but not with the other outcomes. In as-treated analyses, warfarin use was associated with reduced mortality (HR, 0.84; 95% CI, 0.73-0.97). Limitations Short observation period, limited number of nonfatal events, limited generalizability of results to more affluent patients. Conclusions In hemodialysis patients with incident AF, warfarin use was marginally associated with reduced risk of ischemic stroke, and there was a signal toward reduced mortality in as-treated analyses. These results support clinical equipoise regarding the use of warfarin in hemodialysis patients and underscore the need for randomized trials to fill this evidence gap.
Atrial fibrillation (AF) may be clinically silent and therefore undiagnosed. To date, no estimates of the direct medical cost of undiagnosed AF exist. We estimated the United States (US) incremental ...cost burden of undiagnosed nonvalvular AF nationally using administrative claims data. To calculate the incremental costs of undiagnosed AF, we compared annual medical costs (in 2014 US Dollars) for patients with AF compared to propensity-matched controls and multiplied this by estimates of undiagnosed AF prevalence derived from the same data sources. The study population included US residents aged ≥18 years with 24 months of continuous enrollment drawn from 2 large administrative claims databases. Mean per capita medical spending for patients with AF aged from 18 to 64 year was $38,861 (95% confidence interval CI $35,781 to $41,950) compared to $28,506 (95% CI $28,409 to $28,603) for similar patients without AF (incremental cost difference $10,355, p <0.001); total spending for patients aged ≥65 years with AF was $25,322 (95% CI $25,049 to $25,595) compared to $21,706 (95% CI $21,563 to $21,849) for similar patients without AF (incremental cost difference $3,616, p <0.001). Using estimates of the US prevalence of undiagnosed AF (596,000) drawn from the same data, we estimated that the US incremental cost burden of undiagnosed nonvalvular AF is $3.1 billion (95% CI $2.7 to $3.7 billion). In conclusion, the direct medical costs for patients with undiagnosed AF are greater than patients with similar observable characteristics without AF and strategies to identify and treat patients with undiagnosed AF could lead to sizable reductions in stroke sequelae and associated costs.
Abstract Objectives This study aimed to evaluate the cost-effectiveness of the CardioMEMS (CardioMEMS Heart Failure System, St Jude Medical Inc, Atlanta, Georgia) device in patients with chronic ...heart failure. Background The CardioMEMS device, an implantable pulmonary artery pressure monitor, was shown to reduce hospitalizations for heart failure and improve quality of life in the CHAMPION (CardioMEMS Heart Sensor Allows Monitoring of Pressure to Improve Outcomes in NYHA Class III Heart Failure Patients) trial. Methods We developed a Markov model to determine the hospitalization, survival, quality of life, cost, and incremental cost-effectiveness ratio of CardioMEMS implantation compared with usual care among a CHAMPION trial cohort of patients with heart failure. We obtained event rates and utilities from published trial data; we used costs from literature estimates and Medicare reimbursement data. We performed subgroup analyses of preserved and reduced ejection fraction and an exploratory analysis in a lower-risk cohort on the basis of the CHARM (Candesartan in Heart failure: Reduction in Mortality and Morbidity) trials. Results CardioMEMS reduced lifetime hospitalizations (2.18 vs. 3.12), increased quality-adjusted life-years (QALYs) (2.74 vs. 2.46), and increased costs ($176,648 vs. $156,569), thus yielding a cost of $71,462 per QALY gained and $48,054 per life-year gained. The cost per QALY gained was $82,301 in patients with reduced ejection fraction and $47,768 in those with preserved ejection fraction. In the lower-risk CHARM cohort, the device would need to reduce hospitalizations for heart failure by 41% to cost less than $100,000 per QALY gained. The cost-effectiveness was most sensitive to the device’s durability. Conclusions In populations similar to that of the CHAMPION trial, the CardioMEMS device is cost-effective if the trial effectiveness is sustained over long periods. Post-marketing surveillance data on durability will further clarify its value.
Background Atrial fibrillation and flutter (AF, collectively) cause stroke. We evaluated whether treating specialty influences warfarin prescription in patients with newly diagnosed AF. Methods In ...the TREAT-AF study, we used Veterans Health Administration health record and claims data to identify patients with newly diagnosed AF between October 2004 and November 2008 and at least 1 internal medicine/primary care or cardiology outpatient encounter within 90 days after diagnosis. The primary outcome was prescription of warfarin. Results In 141,642 patients meeting the inclusion criteria, the mean age was 72.3 ± 10.2 years, 1.48% were women, and 25.8% had cardiology outpatient care. Cardiology-treated patients had more comorbidities and higher mean CHADS2 scores (1.8 vs 1.6, P < .0001). Warfarin use was higher in cardiology-treated vs primary care only–treated patients (68.6% vs 48.9%, P < .0001). After covariate and site-level adjustment, cardiology care was significantly associated with warfarin use (odds ratio OR 2.05, 95% CI 1.99-2.11). These findings were consistent across a series of adjusted models (OR 2.05-2.20), propensity matching (OR 1.98), and subgroup analyses (OR 1.58-2.11). Warfarin use in primary-care-only patients declined from 2004 to 2008 (51.6%-44.0%, P < .0001), whereas the adjusted odds of warfarin receipt with cardiology care (vs primary care) increased from 2004 to 2008 (1.88-2.24, P < .0001). Conclusion In patients with newly diagnosed AF, we found large differences in anticoagulation use by treating specialty. A divergent 5-year trend of risk-adjusted warfarin use was observed. Treating specialty influences stroke prevention care and may impact clinical outcomes.
The evidence of direct oral anticoagulants (DOACs) usage for venous thromboembolism (VTE) in patients at extremes of body weight or mass index is limited. In such situations, warfarin may be more ...frequently used. We investigated warfarin time in the therapeutic international normalized ratio range (TTR) and DOAC adherence based on the calculated proportion of days covered (PDC) by pill coverage from a DOAC prescription in patients with VTE across all body sizes. Using data from the Veterans Health Administration (VA), we identified first-time patients with VTE between 2013 and 2018 treated with warfarin or DOACs. We analyzed 28,245 patients with warfarin TTR (N = 10,167) or DOAC PDC(N = 18,078). For warfarin-treated patients after index VTE, mean TTR was lower over shorter treatment durations (TTR 30 vs TTR 180 mean ± SD: 43.8% ± 33.5% vs 58.8% ± 23.5%). Mean TTR over 180 days after VTE was lowest for patients <60 kg (TTR 180 mean ± SD: <60kg: 49.3% ± 24.2% vs ≥60 to <100 kg: 57.8% ± 23.4%; P < .0001). For DOAC-treated patients over 180 days after index VTE, mean PDC was lowest for patients <60 kg (PDC 180 mean ± SD: < 60kg: 76.9% ± 33.2% vs ≥ 60 to <100 kg: 83.6% ± 27.7%; P < .0001).
Most DOAC-treated patients attained sufficient adherence across the body size spectrum while warfarin-treated patients <60kg were at risk for low TTR.
Background We sought to evaluate the prognostic performance of the CHADS2 score for prediction of ischemic stroke/transient ischemic attack (TIA) in subjects with coronary heart disease (CHD) without ...atrial fibrillation (AF). Methods In 916 nonanticoagulated outpatients with stable CHD and no AF by baseline electrocardiogram, we calculated CHADS2 scores (congestive heart failure, hypertension, age ≥75 years, diabetes 1 point each, and prior stroke or TIA 2 points). The primary outcome was time to ischemic stroke or TIA over a mean follow-up of 6.4 ± 2.3 years. Results Over 5,821 person-years of follow-up, 40 subjects had an ischemic stroke/TIA (rate 0.69/100 person-years, 95% CI 0.50-0.94). Compared with subjects with low (0-1) CHADS2 scores, those with intermediate (2-3) and high (4-6) CHADS2 scores had an increased rate of stroke/TIA, even after adjustment for age, tobacco, antiplatelet therapy, statins, and angiotensin inhibitors (CHADS2 score 2-3: HR 2.4, 95% CI 1.1-5.3, P = .03; CHADS2 score 4-6: HR 4.0, 95% CI 1.5-10.6, P = .006). Model discrimination (c-statistic = 0.65) was comparable with CHADS2 model fit in published AF-only cohorts. Conclusions The CHADS2 score predicts ischemic stroke/TIA in subjects with stable CHD and no baseline AF. The event rate in non-AF subjects with high CHADS2 scores (5-6) was comparable with published rates in AF patients with moderate CHADS2 scores (1-2), a population known to derive benefit from stroke prevention therapies. These findings should inform efforts to determine whether stroke prevention therapies or screening for silent AF may benefit subjects with stable CHD and high CHADS2 scores.
Abstract Objectives This study sought to explore gender differences in real-world outcomes after catheter ablation of atrial fibrillation (AF). Background Compared with men, women with AF have ...greater thromboembolic risk and tend to be more symptomatic. Catheter ablation is generally more effective than antiarrhythmic drug therapy alone. However, there are limited data on the influence of gender on AF ablation outcomes. Methods We analyzed medical claims of 45 million U.S. patients enrolled in a variety of employee-sponsored and fee-for-service plans. We identified patients who underwent an AF ablation from 2007 to 2011 and evaluated 30-day safety and 1-year effectiveness outcomes. Results Of the 21,091 patients who underwent an AF ablation, 7,460 (29%) were female. Women, compared with men, were older (62 ± 11 years vs. 58 ± 11 years), had higher CHADS2 (1.2 ± 1.1 vs. 1.0 ± 1.0), higher CHA2 DS2 -VASc (2.9 ± 1.5 vs. 1.6 ± 1.4), and higher Charlson comorbidity index scores (1.2 ± 1.3 vs. 1.0 ± 1.2) (p < 0.001 for all). Following ablation, women had higher risk of 30-day complications of hemorrhage (2.7% vs. 2.0%; p < 0.001) and tamponade (3.8% vs. 2.9%; p < 0.001). In multivariable analyses, women were more likely to have a rehospitalization for AF (adjusted hazard ratio: 1.12; p = 0.009), but less likely to have repeat AF ablation (adjusted hazard ratio: 0.92; p = 0.04) or cardioversion (adjusted hazard ratio: 0.75; p < 0.001). Conclusions Women have increased hospitalization rates after AF ablation and are more likely to have a procedural complication. Despite the higher rate of hospital admissions for AF after ablation, women were less likely to undergo repeat ablation or cardioversion. These data call for greater examination of barriers and facilitators to sustain rhythm control strategies in women.
PDF
