Direct Oral Anticoagulant Adherence of Patients With Atrial Fibrillation Transitioned from Warfarin.

Background Reduced time in international normalized ratio therapeutic range (TTR) limits warfarin safety and effectiveness. In patients switched from warfarin to direct oral anticoagulants (DOACs), patient factors associated with low TTR could also increase risk of DOAC nonadherence. We investigated the relationship between warfarin TTR and DOAC adherence in warfarin-treated patients with atrial fibrillation switched to DOAC. Methods and Results Using data from the Veterans Health Administration, we identified patients with atrial fibrillation switched from warfarin to DOAC (switchers) or treated with warfarin alone (non-switchers). Logistic regression was used to evaluate association between warfarin TTR and DOAC adherence. We analyzed 128 605 patients (age, 71±9; 1.6% women; CHA2DS2-VASc 3.5±1.6); 32 377 switchers and 96 228 non-switchers. In 8016 switchers with international normalized ratio data to calculate 180-day TTR before switch, TTR was low (median 0.45; IQR, 0.26-0.64). Patients with TTR <0.5 were more likely to be switched to DOAC (odds ratio [OR],1.68 [95% CI,1.62-1.74], P<0.0001), as were those with TTR <0.6 or TTR <0.7. Proportion of days covered ≥0.8 was achieved by 76% of switchers at 365 days. In low-TTR individuals, proportion of days covered ≥0.8 was achieved by 70%, 72%, and 73% of switchers with TTR <0.5, 0.6, and 0.7, respectively. After multivariable adjustment, TTR <0.5 decreased odds of achieving 365-day proportion of days covered ≥0.8 (OR, 0.49; 0.43-0.57, P<0.0001), with similar relationships for TTR <0.6 and TTR <0.7. In non-switchers with TTR <0.5, long-term TTR remained low. Conclusions In patients with atrial fibrillation switched from warfarin to DOAC, most achieved adequate DOAC adherence despite low pre-switch TTRs. However, TTR trajectories remained low in non-switchers. Patients with low warfarin TTR more consistently achieved treatment targets after switching to DOACs, although adherence-oriented interventions may be beneficial.

Incidence and outcomes of patients with atrial fibrillation and major bleeding complications: from the TREAT-AF study.

PURPOSE: Optimal stroke prevention strategies for patients with atrial fibrillation (AF) who experience a major bleed are poorly defined. We sought to estimate the effectiveness and safety of oral anticoagulation (OAC) represcription after an OAC contraindication. METHODS: TREAT-AF is a retrospective cohort study of patients with newly diagnosed AF (2004-2012), treated in the Veterans Health Administration. From this cohort, we identified patients with a contraindication to OAC after AF diagnoses, defined as incident intracranial bleeding, non-intracranial bleeding requiring hospitalization, or unrepaired cerebral aneurysm or aortic dissection. We used multivariate Cox proportional hazards to estimate the association of OAC prescription in the 90 days following OAC contraindication to ischemic stroke and rebleeding. RESULTS: Among 167,190 patients with newly diagnosed AF (70 ± 11 years, 1.7% female, CHA2DS2-VASc 2.7 ± 1.7), 19,285 patients (11.5%) had an incident bleed (n = 18,342) or an unrepaired cerebral aneurysm or aortic dissection (n = 943). For OAC-contraindicated patients with a CHA2DS2-VASc ≥2 (N = 16,194), OAC was represcribed in 4075 patients (25%) and was associated with a higher risk of non-intracranial bleeding (HR 1.49; 95% CI 1.37-1.61; p < 0.0001) but no difference in intracranial bleeding. There was a trend toward decreased stroke risk (HR 0.85; 95% CI 0.71-1.02; p 0.09). CONCLUSIONS: Development of contraindication to OAC after diagnosis of AF is common (11.5%), with most events requiring hospitalization. OAC reinitiation was associated with non-intracranial bleeding risk, with a trend toward reduced stroke risk. These data suggest that stroke prevention approaches after major bleeding events could be beneficial if bleeding risk can be successfully mitigated.

Sex Differences in Oral Anticoagulation and Outcomes of Stroke and Intracranial Bleeding in Newly Diagnosed Atrial Fibrillation.

Background Female sex is an independent predictor of stroke in patients with atrial fibrillation (AF). Older data suggest undertreatment with anticoagulation among women compared with men. However, it is unknown if novel therapies and updated guidelines have impacted sex differences in AF treatment and outcomes. Methods and Results We performed a retrospective cohort study of 2.3 million women and men with a new diagnosis of AF and CHA2DS2-VASc ≥2 from Marketscan US commercial claims data from 2008 to 2015 to determine whether women with AF remain undertreated and whether this difference mediates observed differences in outcomes. There were 358 649 patients with newly diagnosed AF (43% women). Compared with men, women were older, with higher CHA2DS2-VASc scores, and higher comorbidity burden (P<0.0001 for all). Oral anticoagulation-eligible women with CHA2DS2-VASc scores ≥2 were more likely to not receive anticoagulation (50.0% women versus 43.9% men). Women, compared with men, had a higher risk of ischemic stroke (adjusted hazard ratio [aHR], 1.27; 95% CI, 1.21-1.32; P<0.0001) and hospitalization (aHR, 1.06; 95% CI, 1.05-1.07, P<0.0001) but had a lower risk of intracranial bleeding (aHR, 0.91; 95% CI, 0.83-0.99, P=0.03). In mediation analysis, nonreceipt of oral anticoagulation partially mediated the observed increased risk of stroke and decreased risk of intracranial bleeding in women. Conclusions In the care of newly diagnosed AF in the United States, women, compared with men, are less likely to receive oral anticoagulation. This appears to mediate the increased risk of both stroke and hospitalization but also appears to mediate lower observed intracranial bleeding risk.

Appropriateness of Direct Oral Anticoagulant Dosing in Patients With Atrial Fibrillation: Insights From the Veterans Health Administration.

BACKGROUND: Direct oral anticoagulants (DOACs) have strict dosing guidelines, but recent studies indicate that inappropriate dosing is common, particularly in chronic kidney disease (CKD), for which it has been reported to be as high as 43%. Since 2011, the Veterans Health Administration (VA) has implemented anticoagulation management programs for DOACs, generally led by pharmacists, which has previously been shown to improve medication adherence. OBJECTIVE: We investigated the prevalence of overdosing and underdosing of DOACs in the VA. METHODS: Using data from the TREAT-AF cohort study (The Retrospective Evaluation and Assessment of Therapies in AF), we identified VA patients with newly diagnosed atrial fibrillation (AF) and receipt of a DOAC between 2003 and 2015. We classified dosing as correct, overdosed, or underdosed based on the Food and Drug Administration-approved dosing criteria. RESULTS: Of 230 762 patients, 5060 received dabigatran (77.3%) or rivaroxaban (22.7%) within 90 days of AF diagnosis (age 69 [10[ years; CHA2DS2-VASc 1.6 [1.4]), of which 1312 (25.9%) had CKD based on estimated glomerular filtration rate <60. Overall, 93.6% of patients, 83.2% with CKD, received appropriate DOAC dosing. Incorrect dosing increased with worsening renal function. CONCLUSION: Compared to recent studies of commercial payers and health-care systems, incorrect dosing of DOACs is less common across the VA. Pharmacist-led DOAC management or similar anticoagulation management interventions may reduce the risk of incorrect dosing across health-care systems.

Atrial Fibrillation Burden Signature and Near-Term Prediction of Stroke: A Machine Learning Analysis.

BACKGROUND: Atrial fibrillation (AF) increases the risk of stroke 5-fold and there is rising interest to determine if AF severity or burden can further risk stratify these patients, particularly for near-term events. Using continuous remote monitoring data from cardiac implantable electronic devices, we sought to evaluate if machine learned signatures of AF burden could provide prognostic information on near-term risk of stroke when compared to conventional risk scores. METHODS AND RESULTS: We retrospectively identified Veterans Health Administration serviced patients with cardiac implantable electronic device remote monitoring data and at least one day of device-registered AF. The first 30 days of remote monitoring in nonstroke controls were compared against the past 30 days of remote monitoring before stroke in cases. We trained 3 types of models on our data: (1) convolutional neural networks, (2) random forest, and (3) L1 regularized logistic regression (LASSO). We calculated the CHA2DS2-VASc score for each patient and compared its performance against machine learned indices based on AF burden in separate test cohorts. Finally, we investigated the effect of combining our AF burden models with CHA2DS2-VASc. We identified 3114 nonstroke controls and 71 stroke cases, with no significant differences in baseline characteristics. Random forest performed the best in the test data set (area under the curve [AUC]=0.662) and convolutional neural network in the validation dataset (AUC=0.702), whereas CHA2DS2-VASc had an AUC of 0.5 or less in both data sets. Combining CHA2DS2-VASc with random forest and convolutional neural network yielded a validation AUC of 0.696 and test AUC of 0.634, yielding the highest average AUC on nontraining data. CONCLUSIONS: This proof-of-concept study found that machine learning and ensemble methods that incorporate daily AF burden signature provided incremental prognostic value for risk stratification beyond CHA2DS2-VASc for near-term risk of stroke.

Site Variation and Outcomes for Antithrombotic Therapy in Atrial Fibrillation Patients After Percutaneous Coronary Intervention.

BACKGROUND: Patients with atrial fibrillation (AF) treated with percutaneous coronary intervention (PCI) require multiple antithrombotic therapies. The optimal strategy is debated suggesting increased treatment variation. This study sought to characterize site-level variation in antithrombotic therapies in AF patients after PCI and determine the association with outcomes. METHODS: Using the retrospective TREAT-AF study (The Retrospective Evaluation and Assessment of Therapies in AF) from the Veterans Health Administration, patients with newly diagnosed, nonvalvular AF between 2004 and 2015 followed by a PCI with a P2Y12-antagonist prescription were identified. Patients were grouped according to the therapy dispensed 7 days before until 30 days after the PCI: oral anticoagulation plus platelet inhibition (OAC+PI) or platelet inhibition only. A combined outcome of death, myocardial infarction, stroke, or major bleeding was assessed 1 year after PCI and Cox regression was performed to estimate hazard ratios. RESULTS: Of 230 762 patients with newly diagnosed AF, 4042 (1.8%) underwent PCI and received a P2Y12-antagonist during the observation period (age, 67±9 years; CHA2DS2-VASc, 2.7±1.7; HAS-BLED, 2.6±1.2). Among these, 47% were prescribed OAC+PI, and 53% platelet inhibition only 7 days before until 30 days after the PCI. Across 63 sites, the use of OAC+PI ranged from 19% to 66%. Prescription of OAC+PI was independently associated with a reduction in the combined outcome of death, myocardial infarction, stroke, or major bleeding compared with platelet inhibition only (adjusted hazard ratio, 0.85; 95% CI, 0.73-0.99; P=0.033). CONCLUSIONS: In patients with established AF undergoing PCI, the use of OAC+PI varied substantially across sites in the 30 days post-PCI. Anticoagulation appeared to be underutilized but was associated with improved outcomes. Strategies to promote OAC+PI and minimize site variation may be useful, particularly in light of recent randomized trials.

Urinary tract infection after catheter ablation of atrial fibrillation.

BACKGROUND: Urinary tract infection (UTI) is common after surgical procedures and a quality improvement target. For non-surgical procedures such as catheter ablation of atrial fibrillation (AF), UTI risk has not been characterized. We sought to determine incidence and risk factors of UTI after AF ablation and risk variation across sites. METHODS: Using Marketscan commercial claims databases, we performed a retrospective cohort study of patients who underwent AF ablation from 2007 to 2011. The primary outcome was UTI diagnosis within 30 days after ablation. We performed multivariate analyses to determine risk factors for UTI and risk of sepsis within 30 days after ablation with UTI as the predictor variable. Median odds ratio was used to quantify UTI site variation. RESULTS: Among 21 091 patients (age 59.2 ± 10.9; 29.1% female; CHA2 DS2 -VASc 2.0 ± 1.6), 622 (2.9%) were diagnosed with UTI within 30 days. In multivariate analyses, UTI was independently associated with age, female sex, prior UTI, and general anesthesia (all P < .01). UTI diagnosis was associated with a substantial increased risk of sepsis within 30 days (5.0% vs. 0.3%; odds ratio 17.5; 95% confidence interval [CI] 10.8-28.2; P < .0001). Among 416 sites, 211 had at least one UTI. Among these 211 sites, the incidence of postablation UTI ranged from 0.7 to 26.7% (median: 5.4%; Interquartile Range (IQR): 3.0-7.1%; 95th percentile: 14.3%; median odds ratio: 1.45; 95% CI 1.41-1.50). CONCLUSIONS: UTI after AF ablation is not uncommon and varies substantially across sites. Consideration of UTI as a quality measure and interventions targeted at high-risk patients or sites warrant consideration.

Practice Variation in Anticoagulation Prescription and Outcomes After Device-Detected Atrial Fibrillation.

BACKGROUND: Device-detected atrial fibrillation (AF) is associated with increased risk of stroke; however, there are no clearly defined thresholds of AF burden at which to initiate oral anticoagulation (OAC). We sought to describe OAC prescription practice variation in response to new device-detected AF and the association with outcomes. METHODS: We performed a retrospective cohort study using data from the Veterans Health Administration linked to remote monitoring data that included day-level AF burden. We included patients with cardiac implantable electronic devices and remote monitoring from 2011 to 2014, CHA2DS2-VASc score ≥2, and no prior stroke or OAC receipt in the preceding 2 years. We determined the proportion of patients prescribed OAC within 90 days after new device-detected AF across a range of AF thresholds (≥6 minutes to >24 hours) and examined site variation in OAC prescription. We used multivariable Cox proportional hazards regressions to determine the association of OAC prescription with stroke by device-detected AF burden. RESULTS: Among 10 212 patients with cardiac implantable electronic devices, 4570 (45%), 3969 (39%), 3263 (32%), and 2469 (24%) had device-detected AF >6 minutes, >1 hour, >6 hours, and >24 hours, respectively. For device-detected AF >1 hour, 1712 patients met inclusion criteria (72±10 years; 1.5% female; CHA2DS2-VASc score 4.0±1.4; HAS-BLED score 2.6±1.1). The proportion receiving OAC varied based on device-detected AF burden (≥6 minutes: 272/2101 [13%]; >1 hour: 273/1712 [16%]; >6 hours: 263/1279 [21%]; >24 hours: 224/818 [27%]). Across 52 sites (N=1329 patients), there was substantial site-level variation in OAC prescription after device-detected AF >1 hour (median, 16%; range, 3%-67%; median odds ratio, 1.56 [95% credible interval, 1.49-1.71]). In adjusted models, OAC prescription after device-detected AF >24 hours was associated with reduced stroke risk (hazard ratio, 0.28; 95% CI, 0.10-0.81; P=0.02), although the propensity-adjusted model was significant when AF lasted at least 6 minutes. CONCLUSIONS: Among veterans with cardiac implantable electronic devices, device-detected AF is common. There is large practice variation in 90-day OAC initiation after new device-detected AF, with low rates of treatment overall, even for episodes that last >24 hours. The strongest association of OAC with reduction in stroke was observed after device-detected AF >24 hours. Randomized trials are needed to confirm these observational findings.

Real-World Comparison of Classes IC and III Antiarrhythmic Drugs as an Initial Rhythm Control Strategy in Newly Diagnosed Atrial Fibrillation: From the TREAT-AF Study.

OBJECTIVES: In this study the authors investigated effectiveness and safety of an initial treatment strategy with class IC or class III antiarrhythmic drugs (AAD) for newly diagnosed atrial fibrillation (AF) or atrial flutter (AFL). BACKGROUND: There is limited evidence to guide optimal AAD selection for rhythm control in newly diagnosed AF/AFL. METHODS: Using data from TREAT-AF (The Retrospective Evaluation and Assessment of Therapies in AF), the authors performed a retrospective cohort study of patients with AF/AFL from 2004 to 2014 and class IC or class III AAD prescription within 90 days following diagnosis. Patients with prior myocardial infarction, heart failure, or end-stage renal disease were excluded. Inverse probability treatment weighted propensity scores were used to evaluate the association of AAD class on hospitalization and cardiovascular events. To evaluate residual confounding, falsification outcomes were evaluated. RESULTS: A total of 230,762 patients developed newly diagnosed AF/AFL during the study period. Of those, 3,973 patients (1.7%) were prescribed class IC and 6,909 (3.0%) were prescribed class III AAD. Median follow-up was 4.9 years. After inverse probability treatment weighted adjustment, class IC medications were associated with lower risk of hospitalizations for AF/AFL (hazard ratio [HR]: 0.77; 95% confidence interval [CI]: 0.73 to 0.81), cardiovascular disease (HR: 0.78; 95% CI: 0.75 to 0.81), heart failure (HR: 0.70; 95% CI: 0.64 to 0.76), and lower incidence of ischemic stroke (HR: 0.74; 95% CI: 0.65 to 0.85). Similar results were found in CHADS2 (Congestive Heart Failure, Hypertension, Age ≥75 Years, Diabetes Mellitus, Prior Stroke, Transient Ischemic Attack, or Thromboembolism) 0 or 1 and CHA2DS2-VASc (Congestive Heart Failure, Hypertension, Age ≥75 Years, Diabetes Mellitus, Prior Stroke, Transient Ischemic Attack, or Thromboembolism, Vascular Disease, Age 65 to 74 Years, Sex) 0 or 1 subgroups. Falsification analyses for outcomes of urinary tract infection, pneumonia, and hip fracture were generally nonsignificant. CONCLUSIONS: Prescription of class IC AAD as initial treatment for newly diagnosed AF/AFL, compared with prescription of class III AAD, may be associated with lower risk of hospitalization and cardiovascular events.

Secular trends in success rate of catheter ablation for atrial fibrillation: The SMASH-AF cohort.

BACKGROUND: Approaches, tools, and technologies for atrial fibrillation (AF) ablation have evolved significantly since its inception. We sought to characterize secular trends in AF ablation success rates. METHODS: We performed a systematic review and meta-analysis of AF ablation from January 1, 1990, to August 1, 2016, searching PubMed, Scopus, and Cochrane databases. Major exclusion criteria were insufficient outcome reporting and ablation strategies that were not prespecified and uniform. We stratified treatment arms by AF type (paroxysmal AF; nonparoxysmal AF) and analyzed single-procedure outcomes. Multivariate meta-regressions analyzed effects of study, patient, and procedure characteristics on success rate trends. Registered in PROSPERO (CRD42016036549). RESULTS: A total of 180 trials and observational studies with 28,118 patients met inclusion. For paroxysmal AF ablation studies, unadjusted success rate summary estimates ranged from 73.1% in 2003 to 77.1% in 2016, increasing by 0.9%/year (95% CI 0.4%-1.4%; P = .001; I2 = 90%). After controlling for study design and patient demographics, rate of improvement in success rate summary estimate increased (1.6%/year; 95% CI 0.9%-2.2%; P = .001; I2 = 87%). For nonparoxysmal AF ablation studies, unadjusted success rate summary estimates ranged from 70.0% in 2010 to 64.3% in 2016 (1.1%/year; 95% CI -1.3% to 3.5%; P = .37; I2 = 85%), with no improvement in multivariate analyses. CONCLUSIONS: Despite substantial research investment and health care expenditure, improvements in AF ablation success rates have been incremental. Meaningful improvements may require major paradigm or technology changes, and evaluation of clinical outcomes such as mortality and quality of life may prove to be important going forward.

Efficacy of Ablation Lesion Sets in Addition to Pulmonary Vein Isolation for Paroxysmal Atrial Fibrillation: Findings From the SMASH - AF Meta-Analysis Study Cohort.

Background The objective was to explore the efficacy of ablation lesion sets in addition to pulmonary vein isolation ( PVI ) for paroxysmal atrial fibrillation. The optimal strategy for catheter ablation of paroxysmal atrial fibrillation is debated. Methods and Results The SMASH-AF (Systematic Review and Meta-analysis of Ablation Strategy Heterogeneity in Atrial Fibrillation) study cohort includes trials and observational studies identified in PubMed, Scopus, and Cochrane databases from January 1 1990, to August 1, 2016. We included studies reporting single procedure paroxysmal atrial fibrillation ablation success rates. Exclusion criteria included insufficient reporting of outcomes, ablation strategies that were not prespecified and uniform, and a sample size of fewer than 40 patients. We analyzed lesion sets performed in addition to PVI ( PVI plus) using multivariable random-effects meta-regression to control for patient, study, and procedure characteristics. The analysis included 145 total studies with 23 263 patients ( PVI- only cohort: 115 studies, 148 treatment arms, 16 500 patients; PVI plus cohort: 39 studies; 46 treatment arms, 6763 patients). PVI plus studies, as compared with PVI -only studies, included younger patients (56.7 years versus 58.8 years, P=0.001), fewer women (27.2% versus 32.0% women, P=0.002), and were more methodologically rigorous with longer follow-up (29.5 versus 17.1 months, P 0.004) and more randomization (19.4% versus 11.8%, P<0.001). In multivariable meta-regression, PVI plus studies were associated with improved success (7.6% absolute improvement [95% CI, 2.6-12.5%]; P<0.01, I2=88%), specifically superior vena cava isolation (4 studies, 4 treatment arms, 1392 patients; 15.1% absolute improvement [95% CI, 2.3-27.9%]; P 0.02, I2=87%). However, residual heterogeneity was large. Conclusions Across the paroxysmal atrial fibrillation ablation literature, PVI plus ablation strategies were associated with incremental improvements in success rate. However, large residual heterogeneity complicates evidence synthesis.

Association of Healthcare Plan with atrial fibrillation prescription patterns.

BACKGROUND: Atrial fibrillation (AF) is treated by many types of physician specialists, including primary care physicians (PCPs). Health plans have different policies for how patients encounter these providers, and these may affect selection of AF treatment strategy. HYPOTHESIS: We hypothesized that healthcare plans with PCP-gatekeeping to specialist access may be associated with different pharmacologic treatments for AF. METHODS: We performed a retrospective cohort study using a commercial pharmaceutical claims database. We utilized logistic regression models to compare odds of prescription of oral anticoagulant (OAC), non-vitamin K-dependent oral anticoagulant (NOAC), rate control, and rhythm control medications used to treat AF between patients with PCP-gated healthcare plans (eg, HMO, EPO, POS) and patients with non-PCP-gated healthcare plans (eg, PPO, CHDP, HDHP, comprehensive) between 2007 and 2012. We also calculated median time to receipt of therapy within 90 days of index AF diagnosis. RESULTS: We found similar odds of OAC prescription at 90 days following new AF diagnosis in patients with PCP-gated plans compared to those with non-PCP-gated plans (OR: OAC 1.01, P = 0.84; warfarin 1.05, P = 0.08). Relative odds were similar for rate control (1.17, P < 0.01) and rhythm control agents (0.93, P = 0.03). However, PCP-gated plan patients had slightly lower likelihood of being prescribed NOACs (0.82, P = 0.001) than non-gated plan patients. Elapsed time until receipt of medication was similar between PCP-gated and non-gated groups across drug classes. CONCLUSIONS: Pharmaceutical claims data do not suggest that PCP-gatekeeping by healthcare plans is a structural barrier to AF therapy, although it was associated with lower use of NOACs.

Geographic and racial representation and reported success rates of studies of catheter ablation for atrial fibrillation: Findings from the SMASH-AF meta-analysis study cohort.

INTRODUCTION: We performed a systematic review and meta-analysis of geographic and racial representation and reported success rates of studies of catheter ablation for atrial fibrillation (AF). METHODS AND RESULTS: We searched PubMed, Scopus, and Cochrane databases from 1/1/1990 to 8/1/2016 for trials and observational studies reporting AF ablation outcomes. Major exclusion criteria were insufficient reporting of outcomes, non-English language articles, and ablation strategies that were not prespecified and uniform. We described geographic and racial representation and single-procedure ablation success rates by country, controlling for patient demographics and study design characteristics. The analysis cohort included 306 studies (49,227 patients) from 28 countries. Over half of the paroxysmal (PAF) and nonparoxysmal AF (NPAF) treatment arms were conducted in 5 and 3 countries, respectively. Reporting of race or ethnicity demographics and outcomes were rare (1 study, 0.3%) and nonexistent, respectively. Unadjusted success rates by country ranged from 63.5% to 83.0% for PAF studies and 52.7% to 71.6% for NPAF studies, with substantial variation in patient demographics and study design. After controlling for covariates, South Korea and the United States had higher PAF ablation success rates, with large residual heterogeneity. NPAF ablation success rates were statistically similar by country. CONCLUSIONS: Studies of AF ablation have substantial variation in patient demographics, study design, and reported outcomes by country. There is limited geographic representation of trials and observational studies of AF ablation and a paucity of race- or ethnicity-stratified results. Future AF ablation studies and registries should aim to have broad representation by race, geography, and ethnicity to ensure generalizability.

Treating Specialty and Outcomes in Newly Diagnosed Atrial Fibrillation: From the TREAT-AF Study.

BACKGROUND: Atrial fibrillation (AF) occurs in many clinical contexts and is diagnosed and treated by clinicians across many specialties. This approach has resulted in treatment variations. OBJECTIVES: The goal of this study was to evaluate the association between treating specialty and AF outcomes among patients newly diagnosed with AF. METHODS: Using data from the TREAT-AF (Retrospective Evaluation and Assessment of Therapies in AF) study from the Veterans Health Administration, patients with newly diagnosed, nonvalvular AF between 2004 and 2012 were identified who had at least 1 outpatient encounter with primary care or cardiology within 90 days of the AF diagnosis. Cox proportional hazards regression was used to evaluate the association between treating specialty and AF outcomes. RESULTS: Among 184,161 patients with newly diagnosed AF (age 70 ± 11 years; 1.7% women; CHA2DS2-VASc score 2.6 ± 1.7), 40% received cardiology care and 60% received primary care only. After adjustment for covariates, cardiology care was associated with reductions in stroke (hazard ratio [HR]: 0.91; 95% confidence interval [CI]: 0.86 to 0.96; p < 0.001) and death (HR: 0.89; 95% CI: 0.88 to 0.91; p < 0.0001) and increases in hospitalizations for AF/supraventricular tachycardia (HR: 1.38; 95% CI: 1.35 to 1.42; p < 0.0001) and myocardial infarction (HR: 1.03; 95% CI: 1.00 to 1.05; p < 0.04). The propensity-matched cohort had similar results. In mediation analysis, oral anticoagulation prescription within 90 days of diagnosis may have mediated reductions in stroke but did not mediate reductions in survival. CONCLUSIONS: In patients with newly diagnosed AF, cardiology care was associated with improved outcomes, potentially mediated by early prescription of oral anticoagulation therapy. Although hypothesis-generating, these data warrant serious consideration and study of health care system interventions at the time of new AF diagnosis.