Cost-Effectiveness of Screening Asymptomatic Carotid Stenosis by Atherosclerotic Cardiovascular Risk.

Importance: Extracranial internal carotid artery stenosis (50-99% arterial narrowing) is an important risk factor for ischemic stroke. Yet, the benefits and harms of targeted screening for asymptomatic carotid artery stenosis (ACAS) have not been assessed in population-based studies. Objective: To estimate the cost-effectiveness of one-time, targeted ACAS screening stratified by atherosclerotic cardiovascular disease (ASCVD) risk using the American Heart Association's Pooled Cohort Equations. Design Setting and Participants: We developed a lifetime microsimulation model of ACAS and stroke for a hypothetical cohort representative of US adults aged 50-80 years without stroke history. We used the Cardiovascular Health Study to estimate the probability and severity of ACAS based on individual characteristics (e.g., age, sex, smoking status, blood pressure, and cholesterol). Stroke risks were functions of these characteristics and ACAS severity. In the model, individuals testing positive for >70% stenosis with Duplex ultrasound and a confirmatory diagnostic test undergo revascularization, which may reduce the risk of stroke but also introduces complication risks. Diagnostic performance parameters, revascularization benefits and risks, utility weights, and costs were estimated from published sources. Cost-effectiveness was assessed from the health care sector perspective using a $100,000/quality-adjusted life year (QALY) threshold. Main Outcomes and Measures: Estimated stroke events prevented, lifetime costs, QALYs, and incremental cost-effectiveness ratios (ICERs) associated with ACAS screening. Costs (2023 USD) and QALYs were discounted at 3% annually. Results: We found that screening individuals with a 10-year ASCVD risk >30% was the most cost-effective strategy, with an ICER of $89,000/QALY. This strategy would make approximately 11.9% of the population eligible for screening, averting an estimated 24,084 strokes. Results were sensitive to variations in the efficacy and complication risk of revascularization. In probabilistic sensitivity analysis, screening those in lower ASCVD risk groups (0-20%) only had a 0.6% chance of being cost-effective. Conclusion and Relevance: A one-time screening may only be cost-effective for adults at a relatively high ASCVD risk. Our findings provide a framework that can be adapted as future clinical trial data continue to improve our understanding of the role of revascularization and intensive medical therapy in contemporary stroke prevention secondary to carotid disease.

Cost-Effectiveness of Increased Use of Dual Antiplatelet Therapy After High-Risk Transient Ischemic Attack or Minor Stroke.

BACKGROUND: Rates of dual antiplatelet therapy (DAPT) after high-risk transient ischemic attack or minor ischemic stroke (TIAMIS) are suboptimal. We performed a cost-effectiveness analysis to characterize the parameters of a quality improvement (QI) intervention designed to increase DAPT use after TIAMIS. METHODS AND RESULTS: We constructed a decision tree model that compared current national rates of DAPT use after TIAMIS with rates after implementing a theoretical QI intervention designed to increase appropriate DAPT use. The base case assumed that a QI intervention increased the rate of DAPT use to 65% from 45%. Costs (payer and societal) and outcomes (stroke, myocardial infarction, major bleed, or death) were modeled using a lifetime horizon. An incremental cost-effectiveness ratio <$100 000 per quality-adjusted life year was considered cost-effective. Deterministic and probabilistic sensitivity analyses were performed. From the payer perspective, a QI intervention was associated with $9657 in lifetime cost savings and 0.18 more quality-adjusted life years compared with current national treatment rates. A QI intervention was cost-effective in 73% of probabilistic sensitivity analysis iterations. Results were similar from the societal perspective. The maximum acceptable, initial, 1-time payer cost of a QI intervention was $28 032 per patient. A QI intervention that increased DAPT use to at least 51% was cost-effective in the base case. CONCLUSIONS: Increasing DAPT use after TIAMIS with a QI intervention is cost-effective over a wide range of costs and proportion of patients with TIAMIS treated with DAPT after implementation of a QI intervention. Our results support the development of future interventions focused on increasing DAPT use after TIAMIS.

Prioritizing Quality Measures in Acute Stroke Care : A Cost-Effectiveness Analysis.

BACKGROUND: The American Heart Association and American Stroke Association (AHA/ASA) endorsed 15 process measures for acute ischemic stroke (AIS) to improve the quality of care. Identifying the highest-value measures could reduce the administrative burden of quality measure adoption while retaining much of the value of quality improvement. OBJECTIVE: To prioritize AHA/ASA-endorsed quality measures for AIS on the basis of health impact and cost-effectiveness. DESIGN: Individual-based stroke simulation model. DATA SOURCES: Published literature. TARGET POPULATION: U.S. patients with incident AIS. TIME HORIZON: Lifetime. PERSPECTIVE: Health care sector. INTERVENTION: Current versus complete (100%) implementation at the population level of quality measures endorsed by the AHA/ASA with sufficient clinical evidence (10 of 15). OUTCOME MEASURES: Life-years, quality-adjusted life-years (QALYs), incremental cost-effectiveness ratios, and incremental net health benefits. RESULTS OF BASE-CASE ANALYSIS: Discounted life-years gained from complete implementation would range from 472 (tobacco use counseling) to 34 688 (early carotid imaging) for an annual AIS patient cohort. All AIS quality measures were cost-saving or highly cost-effective by AHA standards (<$50 000 per QALY for high-value care). Early carotid imaging and intravenous tissue plasminogen activator contributed the largest fraction of the total potential value of quality improvement (measured as incremental net health benefit), accounting for 72% of the total value. The top 5 quality measures accounted for 92% of the total potential value. RESULTS OF SENSITIVITY ANALYSIS: A web-based user interface allows for context-specific sensitivity and scenario analyses. LIMITATION: Correlations between quality measures were not incorporated. CONCLUSION: Substantial variation exists in the potential net benefit of quality improvement across AIS quality measures. Benefits were highly concentrated among 5 of 10 measures assessed. Our results can help providers and payers set priorities for quality improvement efforts and value-based payments in AIS care. PRIMARY FUNDING SOURCE: National Institute of Neurological Disorders and Stroke.

Duration of Heightened Risk of Acute Ischemic Stroke After Hospitalization for Acute Systolic Heart Failure.

Background The duration and magnitude of increased stroke risk after a hospitalization for acute systolic heart failure (HF) remains uncertain. Methods and Results The authors performed a retrospective cohort study using claims (2008-2018) from a nationally representative 5% sample of Medicare beneficiaries aged ≥66 years. Cox regression models were fitted separately for the groups with and without acute systolic HF to examine its association with the incidence of ischemic stroke after adjustment for demographics, stroke risk factors, and Charlson comorbidities. Corresponding survival probabilities were used to compute the hazard ratio (HR) in each 30-day interval after discharge. The authors stratified patients by the presence of atrial fibrillation (AF) before or during the hospitalization for acute systolic HF. Among 2 077 501 eligible beneficiaries, 94 641 were hospitalized with acute systolic HF. After adjusting for demographics, stroke risk factors, and Charlson comorbidities, the risk of ischemic stroke was highest in the first 30 days after discharge from an acute systolic HF hospitalization for patients with AF (HR, 2.4 [95% CI, 2.1-2.7]) and without AF (HR, 4.6 [95% CI, 4.0-5.3]). The risk of stroke remained elevated for 60 days in patients with AF (HR, 1.4 [95% CI, 1.2-1.6]) and was not significantly elevated afterward. The risk of stroke remained significantly elevated through 330 days in patients without AF (HR, 2.1 [95% CI, 1.7-2.7]) and was no longer significantly elevated afterward. Conclusions A hospitalization for acute systolic HF is associated with an increased risk of ischemic stroke up to 330 days in patients without concomitant AF.

Cost-Effectiveness of Smoking Cessation Interventions in Patients With Ischemic Stroke and Transient Ischemic Attack.

BACKGROUND: Smoking cessation rates after stroke and transient ischemic attack are suboptimal, and smoking cessation interventions are underutilized. We performed a cost-effectiveness analysis of smoking cessation interventions in this population. METHODS: We constructed a decision tree and used Markov models that aimed to assess the cost-effectiveness of varenicline, any pharmacotherapy with intensive counseling, and monetary incentives, compared with brief counseling alone in the secondary stroke prevention setting. Payer and societal costs of interventions and outcomes were modeled. The outcomes were recurrent stroke, myocardial infarction, and death using a lifetime horizon. Estimates and variance for the base case (35% cessation), costs and effectiveness of interventions, and outcome rates were imputed from the stroke literature. We calculated incremental cost-effectiveness ratios and incremental net monetary benefits. An intervention was considered cost-effective if the incremental cost-effectiveness ratio was less than the willingness-to-pay threshold of $100 000 per quality-adjusted life-year (QALY) or when the incremental net monetary benefit was positive. Probabilistic Monte Carlo simulations modeled the impact of parameter uncertainty. RESULTS: From the payer perspective, varenicline and pharmacotherapy with intensive counseling were associated with more QALYs (0.67 and 1.00, respectively) at less total lifetime costs compared with brief counseling alone. Monetary incentives were associated with 0.71 more QALYs at an additional cost of $120 compared with brief counseling alone, yielding an incremental cost-effectiveness ratio of $168/QALY. From the societal perspective, all 3 interventions provided more QALYs at less total costs compared with brief counseling alone. In 10 000 Monte Carlo simulations, all 3 smoking cessation interventions were cost-effective in >89% of runs. CONCLUSIONS: For secondary stroke prevention, it is cost-effective and potentially cost-saving to deliver smoking cessation therapy beyond brief counseling alone.

Long-Term Risk of Ischemic Stroke among Elderly Survivors of Non-Traumatic Subarachnoid Hemorrhage.

INTRODUCTION: Non-traumatic subarachnoid hemorrhage (SAH) is associated with poor long-term functional outcomes, but the risk of ischemic stroke among SAH survivors is poorly understood. OBJECTIVES: The aim of this study was to evaluate the risk of ischemic stroke among survivors of SAH. METHODS: We performed a retrospective cohort study using claims data from Medicare beneficiaries from 2008 to 2015. The exposure was a diagnosis of SAH, while the outcome was an acute ischemic stroke, both identified using previously validated ICD-9-CM diagnosis codes. We used Cox regression analysis adjusting for demographics and stroke risk factors to evaluate the association between SAH and long-term risk of ischemic stroke. RESULTS: Among 1.7 million Medicare beneficiaries, 912 were hospitalized with non-traumatic SAH. During a median follow-up of 5.2 years (IQR, 2.7-6.7), the cumulative incidence of ischemic stroke was 22 per 1,000 patients per year among patients with SAH, and 7 per 1,000 patients per year in those without SAH. In adjusted Cox models, SAH was associated with an increased risk of ischemic stroke (HR, 2.0; 95% confidence interval, 1.4-2.8) as compared to beneficiaries without SAH. Similar results were obtained in sensitivity analyses, when treating death as a competing risk (sub HR, 3.0; 95% CI, 2.8-3.3) and after excluding ischemic stroke within 30 days of SAH discharge (HR, 1.5; 95% CI, 1.1-2.3). CONCLUSIONS: In a large, heterogeneous national cohort of elderly patients, survivors of SAH had double the long-term risk of ischemic stroke. SAH survivors should be closely monitored and risk stratified for ischemic stroke.

Access to Mechanical Thrombectomy for Ischemic Stroke in the United States.

Background and Purpose: Mechanical thrombectomy helps prevent disability in patients with acute ischemic stroke involving occlusion of a large cerebral vessel. Thrombectomy requires procedural expertise and not all hospitals have the staff to perform this intervention. Few population-wide data exist regarding access to mechanical thrombectomy. Methods: We examined access to thrombectomy for ischemic stroke using discharge data from calendar years 2016 to 2018 from all nonfederal emergency departments and acute care hospitals across 11 US states encompassing 80 million residents. Facilities were classified as hubs if they performed mechanical thrombectomy, gateways if they transferred patients who ultimately underwent mechanical thrombectomy, and gaps otherwise. We used standard descriptive statistics and unadjusted logistic regression models in our primary analyses. Results: Among 205 681 patients with ischemic stroke, 100 139 (48.7% [95% CI, 48.5%­48.9%]) initially received care at a thrombectomy hub, 72 534 (35.3% [95% CI, 35.1%­35.5%]) at a thrombectomy gateway, and 33 008 (16.0% [95% CI, 15.9%­16.2%]) at a thrombectomy gap. Patients who initially received care at thrombectomy gateways were substantially less likely to ultimately undergo thrombectomy than patients who initially received care at thrombectomy hubs (odds ratio, 0.27 [95% CI, 0.25­0.28]). Rural patients had particularly limited access: 27.7% (95% CI, 26.9%­28.6%) of such patients initially received care at hubs versus 69.5% (95% CI, 69.1%­69.9%) of urban patients. For 93.8% (95% CI, 93.6%­94.0%) of patients with stroke at gateways, their initial facility was capable of delivering intravenous thrombolysis, compared with 76.3% (95% CI, 75.8%­76.7%) of patients at gaps. Our findings were unchanged in models adjusted for demographics and comorbidities and persisted across multiple sensitivity analyses, including analyses adjusting for estimated stroke severity. Conclusions: We found that a substantial proportion of patients with ischemic stroke across the United States lacked access to thrombectomy even after accounting for interhospital transfers. US systems of stroke care require further development to optimize thrombectomy access.

Utilization and Availability of Advanced Imaging in Patients With Acute Ischemic Stroke.

BACKGROUND: Recent clinical trials have established the efficacy of endovascular stroke therapy and intravenous thrombolysis using advanced imaging, particularly computed tomography perfusion (CTP). The availability and utilization of CTP for patients and hospitals that treat acute ischemic stroke (AIS), however, is uncertain. METHODS: We performed a retrospective cross-sectional analysis using 2 complementary Medicare datasets, full sample Texas and 5% national fee-for-service data from 2014 to 2017. AIS cases were identified using International Classification of Diseases, NinthRevision and International Classification of Diseases, Tenth Revision coding criteria. Imaging utilization performed in the initial evaluation of patients with AIS was derived using Current Procedural Terminology codes from professional claims. Primary outcomes were utilization of imaging in AIS cases and the change in utilization over time. Hospitals were defined as imaging modality-performing if they submitted at least 1 claim for that modality per calendar year. The National Medicare dataset was used to validate state-level findings, and a local hospital-level cohort was used to validate the claims-based approach. RESULTS: Among 50 797 AIS cases in the Texas Medicare fee-for-service cohort, 64% were evaluated with noncontrast head CT, 17% with CT angiography, 3% with CTP, and 33% with magnetic resonance imaging. CTP utilization was greater in patients treated with endovascular stroke therapy (17%) and intravenous thrombolysis (9%). CT angiography (4%/y) and CTP (1%/y) utilization increased over the study period. These findings were validated in the National dataset. Among hospitals in the Texas cohort, 100% were noncontrast head CT-performing, 77% CT angiography-performing, and 14% CTP-performing in 2017. Most AIS cases (69%) were evaluated at non-CTP-performing hospitals. CTP-performing hospitals were clustered in urban areas, whereas large regions of the state lacked immediate access. CONCLUSIONS: In state-wide and national Medicare fee-for-service cohorts, CTP utilization in patients with AIS was low, and most patients were evaluated at non-CTP-performing hospitals. These findings support the need for alternative means of screening for AIS recanalization therapies.

Gastrointestinal Disorders and Risk of First-Ever Ischemic Stroke.

BACKGROUND AND PURPOSE: Recent studies suggest that alteration of the normal gut microbiome contributes to atherosclerotic burden and cardiovascular disease. While many gastrointestinal diseases are known to cause disruption of the normal gut microbiome in humans, the clinical impact of gastrointestinal diseases on subsequent cerebrovascular disease remains unknown. We conducted an exploratory analysis evaluating the relationship between gastrointestinal diseases and ischemic stroke. METHODS: We performed a retrospective cohort study using claims between 2008 and 2015 from a nationally representative 5% sample of Medicare beneficiaries. We included only beneficiaries ≥66 years of age. We used previously validated diagnosis codes to ascertain our primary outcome of ischemic stroke. In an exploratory manner, we categorized gastrointestinal disorders by anatomic location, disease chronicity, and disease mechanism. We used Cox proportional hazards models to examine associations of gastrointestinal disorder categories and ischemic stroke with adjustment for demographics and established vascular risk factors. RESULTS: Among a mean of 1 725 246 beneficiaries in each analysis, several categories of gastrointestinal disorders were associated with an increased risk of ischemic stroke after adjustment for established stroke risk factors. The most notable positive associations included disorders of the stomach (hazard ratio, 1.17 [95% CI, 1.15-1.19]) and functional (1.16 [95% CI, 1.15-1.17]), inflammatory (1.13 [95% CI, 1.12-1.15]), and infectious gastrointestinal disorders (1.13 [95% CI, 1.12-1.15]). In contrast, we found no associations with stroke for diseases of the anus and rectum (0.97 [95% CI, 0.94-1.00]) or neoplastic gastrointestinal disorders (0.97 [95% CI, 0.94-1.00]). CONCLUSIONS: In exploratory analyses, several categories of gastrointestinal disorders were associated with an increased risk of future ischemic stroke after adjustment for demographics and established stroke risk factors.

Can Pay-for Performance Incentive Levels be Determined Using a Cost-Effectiveness Framework?

BACKGROUND: Healthcare payers in the United States are increasingly tying provider payments to quality and value using pay-for-performance policies. Cost-effectiveness analysis quantifies value in healthcare but is not currently used to design or prioritize pay-for-performance strategies or metrics. Acute ischemic stroke care provides a useful application to demonstrate how simulation modeling can be used to determine cost-effective levels of financial incentives used in pay-for-performance policies and associated challenges with this approach. METHODS AND RESULTS: Our framework requires a simulation model that can estimate quality-adjusted life years and costs resulting from improvements in a quality metric. A monetary level of incentives can then be back-calculated using the lifetime discounted quality-adjusted life year (which includes effectiveness of quality improvement) and cost (which includes incentive payments and cost offsets from quality improvements) outputs from the model. We applied this framework to an acute ischemic stroke microsimulation model to calculate the difference in population-level net monetary benefit (willingness-to-pay of $50 000 to $150 000/quality-adjusted life year) accrued under current Medicare policy (stroke payment not adjusted for performance) compared with various hypothetical pay-for-performance policies. Performance measurement was based on time-to-thrombolytic treatment with tPA (tissue-type plasminogen activator). Compared with current payment, equivalent population-level net monetary benefit was achieved in pay-for-performance policies with 10-minute door-to-needle time reductions (5057 more acute ischemic stroke cases/y in the 0-3-hour window) incentivized by increasing tPA payment by as much as 18% to 44% depending on willingness-to-pay for health. CONCLUSIONS: Cost-effectiveness modeling can be used to determine the upper bound of financial incentives used in pay-for-performance policies, although currently, this approach is limited due to data requirements and modeling assumptions. For tPA payments in acute ischemic stroke, our model-based results suggest financial incentives leading to a 10-minute decrease in door-to-needle time should be implemented but not exceed 18% to 44% of current tPA payment. In general, the optimal level of financial incentives will depend on willingness-to-pay for health and other modeling assumptions around parameter uncertainty and the relationship between quality improvements and long-run quality-adjusted life expectancy and costs.

Symptoms of depression and active smoking among survivors of stroke and myocardial infarction: An NHANES analysis.

Historic concerns about the cardiovascular and neuropsychiatric side effects of smoking-cessation pharmacotherapy have in part limited their use. We sought to evaluate whether depressive symptoms are associated with active smoking among survivors of stroke and myocardial infarction (MI). To do this, we performed a cross-sectional analysis using data from the National Health and Nutrition Examination Survey (2005-2016). We included participants ≥20 years old with prior stroke or MI and any history of smoking. Symptoms of depression, at survey participation, were ascertained using the Patient Health Questionnaire-9. Active smoking was defined using self-report and, secondarily, with cotinine measures. We used logistic regression to evaluate the association between depression and active smoking after adjusting for demographics, smoking-related medical conditions, and health-related behaviors. We found that, among stroke and MI survivors with any history of smoking, 37.9% (95% CI, 34.5-41.3%) reported active smoking and 43.8% (95% CI, 40.3-47.3%) had biochemical evidence of smoking. Rates of active smoking were similar for stroke and MI survivors. Twenty-one percent screened positive for depression. In adjusted models, depression was associated with active smoking in the combined group of stroke and MI survivors (odds ratio, 2.28; 95% CI, 1.24-4.20) and in stroke survivors (odds ratio, 2.97; 95% CI, 1.20-7.38). Tests of heterogeneity by event type did not reveal an interaction. Findings were similar when using cotinine measures. We conclude that symptoms of depression were associated with active smoking among stroke and MI survivors. Stroke and MI survivors with symptoms of depression may require targeted smoking-cessation interventions.

Differences in Diagnostic Evaluation in Women and Men After Acute Ischemic Stroke.

Background Sex differences have been found in stroke risk factors, incidence, treatment, and outcomes. There are conflicting data on whether diagnostic evaluation for stroke may differ between men and women. Methods and Results We performed a retrospective cohort study using inpatient and outpatient claims between 2008 and 2016 from a nationally representative 5% sample of Medicare beneficiaries. We included patients ≥65 years old and hospitalized with ischemic stroke, defined by International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and ICD-10-CM diagnosis codes. Logistic regression was used to determine the association between female sex and the odds of diagnostic testing and specialist evaluation, adjusted for age, race, and number of Charlson comorbidities. Among 78 822 patients with acute ischemic stroke, 58.3% (95% CI, 57.9-58.6%) were women. Female sex was associated with decreased odds of intracranial vessel imaging (odds ratio [OR]: 0.94; 95% CI, 0.91-0.97), extracranial vessel imaging (OR: 0.89; 95% CI, 0.86-0.92), heart-rhythm monitoring (OR: 0.92; 95% CI, 0.87-0.98), echocardiography (OR: 0.92; 95% CI, 0.89-0.95), evaluation by a neurologist (OR: 0.94; 95% CI, 0.91-0.97), and evaluation by a vascular neurologist (OR: 0.94; 95% CI, 0.90-0.97), after adjustment for age, race, and comorbidities. These findings were unchanged in separate sensitivity analyses excluding patients who died during the index hospitalization or were discharged to hospice and excluding patients with atrial fibrillation diagnosed before their index stroke. Conclusions In a nationally representative cohort of Medicare beneficiaries, we found that women with acute ischemic stroke were less likely to be evaluated by stroke specialists and less likely to undergo standard diagnostic testing compared with men.

Cost Effectiveness of Assessing Ultrasound Plaque Characteristics to Risk Stratify Asymptomatic Patients With Carotid Stenosis.

Background Imaging may play an important role in identifying high-risk plaques in patients who have carotid disease and who could benefit from surgical revascularization. We sought to evaluate the cost effectiveness of a decision-making rule based on the ultrasound imaging assessment of plaque echolucency in patients with asymptomatic carotid stenosis. Methods and Results We used a decision-analytic model to project lifetime quality-adjusted life years and costs for 5 stroke prevention strategies: (1) medical therapy only; (2) revascularization if both plaque echolucency and stenosis progression to >90% are present; (3) revascularization only if plaque echolucency is present; (4) revascularization only if stenosis progression >90% is present; or (5) either plaque echolucency or stenosis progression is present. Risks of clinical events, costs, and quality-of-life values were estimated based on published sources and the analysis was conducted from a healthcare system perspective for asymptomatic patients with 70% to 89% carotid stenosis at presentation. Patients who did not undergo revascularization had the highest stroke events (17.6%) and lowest life-years (8.45), while those who underwent revascularization on the basis of either presence of plaque echolucency on ultrasound or progression of carotid stenosis had the lowest stroke events (12.0%) and longest life-years (14.41). The either plaque echolucency or progression-based revascularization group had an incremental cost-effectiveness ratio of $110 000/quality-adjusted life years compared with the plaque echolucency-based strategy, which had an incremental cost-effectiveness ratio of $29 000/quality-adjusted life years compared with the joint echolucency and progression-based strategy. Conclusions Plaque echolucency on ultrasound can be a cost-effective tool to identify patients with asymptomatic carotid artery stenosis most likely to benefit from carotid endarterectomy.

Association Between Intravenous Thrombolysis and Anaphylaxis Among Medicare Beneficiaries With Acute Ischemic Stroke.

Background and Purpose- Allergic reactions, including anaphylaxis, can sometimes occur after intravenous thrombolysis in patients with acute ischemic stroke. However, it remains unclear whether patients with stroke who receive thrombolytic agents face a higher risk of anaphylaxis than those who do not receive thrombolytics. Methods- We performed a retrospective cohort study using inpatient and outpatient claims between 2008 and 2015 from a nationally representative 5% sample of Medicare beneficiaries. We included patients who were ≥65 years old and hospitalized with acute ischemic stroke, defined by validated International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes. Our exposure was treated with an intravenous thrombolytic agent during the index hospitalization (International Classification of Diseases, Ninth Revision, Clinical Modification code 99.10). Our primary outcome was anaphylaxis, defined using an accepted International Classification of Diseases, Ninth Revision, Clinical Modification code algorithm (989.5, 995.0-4, 995.6x, E905, E905.3, E905.5, or E905.8-9). A secondary outcome was anaphylactic shock (995.0 or 995.6x). Multiple logistic regression was used to evaluate the association between intravenous thrombolysis and anaphylaxis after adjustment for demographics, vascular risk factors, the Charlson comorbidity index, exposure to intravenous contrast dye, treatment with mechanical thrombectomy, and history of allergic reactions. Results- Among 66 989 patients with stroke, the 3176 (4.7%) who underwent intravenous thrombolysis more often had atrial fibrillation (47.7% versus 37.4%) and more often received intravenous contrast dye (44.3% versus 21.9%) but were otherwise similar in terms of demographics and comorbidities. Anaphylaxis developed in 17 (0.54%; 95% CI, 0.31%-0.86%) patients who received intravenous thrombolysis versus 45 (0.07%; 95% CI, 0.05%-0.09%) who did not. After adjustment for demographics, comorbidities, contrast dye, mechanical thrombectomy, and history of allergies, there was a significant association between receipt of intravenous thrombolysis and anaphylaxis (odds ratio, 7.8; 95% CI, 4.3-13.9). We found a similar association for anaphylactic shock. Conclusions- Although a rare occurrence, the risk of anaphylaxis among patients with acute ischemic stroke was significantly higher among those who received intravenous thrombolysis.

Association of Aortic Aneurysms and Dissections With Subarachnoid Hemorrhage.

Background It is uncertain whether aortic diseases, such as aneurysm and dissection, are associated with intracranial aneurysm formation and aneurysmal subarachnoid hemorrhage (SAH). Methods and Results We used data on claims between 2008 and 2015 from a nationally representative 5% sample of Medicare beneficiaries. Our exposure variable was hospitalization with an unruptured or ruptured aortic aneurysm or aortic dissection. The outcome was nontraumatic SAH. Variables were ascertained by International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM), diagnosis codes. Survival statistics were used to calculate incidence rates. Cox proportional hazards analysis was used to examine the association between aortic aneurysm/dissection and SAH while adjusting for demographics, vascular risk factors, and Charlson comorbidities. Among 1 781 917 beneficiaries, 32 551 (1.8%) had a documented aortic aneurysm or dissection. During 4.6±2.2 years of follow-up, 2538 patients (0.14%) developed a nontraumatic SAH. The incidence of SAH was 9 (95% CI, 7-11) per 10 000 patients per year in those with aortic aneurysm/dissection compared with 3 (95% CI, 3-3) per 10 000 patients per year in those without aortic aneurysm/dissection. After adjustment for demographics, stroke risk factors, and Charlson comorbidities, patients with aortic aneurysm/dissection faced an increased risk of SAH (hazard ratio, 1.4; 95% CI, 1.02-1.9; P=0.04). Conclusions In a nationally representative sample of Medicare beneficiaries, aortic aneurysm/dissection was associated with an increased risk of nontraumatic SAH.

Sex-based differences in outcomes, 30-day readmissions, and costs following catheter ablation of atrial fibrillation: the United States Nationwide Readmissions Database 2010-14.

AIMS: Although catheter ablation has emerged as an important therapy for patients with symptomatic atrial fibrillation (AF), there are limited data on sex-based differences in outcomes. We sought to compare in-hospital outcomes and 30-day readmissions of women and men undergoing AF ablation. METHODS AND RESULTS: Using the United States Nationwide Readmissions Database, we analysed patients undergoing AF ablation between 2010 and 2014. Based on ICD-9-CM codes, we identified co-morbidities and outcomes. Multivariable logistic regression and inverse probability-weighting analysis were performed to assess female sex as a predictor of endpoints. Of 54 597 study patients, 20 623 (37.7%) were female. After adjustment for age, co-morbidities, and hospital factors, women had higher rates of any complication [adjusted odds ratio (aOR) 1.39; P < 0.0001], cardiac perforation (aOR 1.39; P = 0.006), and bleeding/vascular complications (aOR 1.49; P < 0.0001). Thirty-day all-cause readmission rates were higher for women compared to men (13.4% vs. 9.4%; P < 0.0001). Female sex was independently associated with readmission for AF/atrial tachycardia (aOR 1.48; P < 0.0001), cardiac causes (aOR 1.40; P < 0.0001), and all causes (aOR 1.25; P < 0.0001). Similar findings were confirmed with inverse probability-weighting analysis. Despite increased complications and readmissions, total costs for AF ablation were lower for women than men due to decreased resource utilization. CONCLUSIONS: Independent of age, co-morbidities, and hospital factors, women have higher rates of complications and readmissions following AF ablation. Sex-based differences and disparities in the management of AF need to be explored to address these gaps in outcomes.

Risk of Atrial Fibrillation in Black Versus White Medicare Beneficiaries With Implanted Cardiac Devices.

Background Black individuals in the United States experience higher rates of ischemic stroke than other racial groups but have lower rates of clinically apparent atrial fibrillation ( AF ). It is unclear whether blacks truly have less AF or simply more undiagnosed AF . Methods and Results We performed a retrospective cohort study using inpatient and outpatient claims from 2009 to 2015 for a 5% nationally representative sample of Medicare beneficiaries. We included patients aged ≥66 years with at least 1 documented Current Procedural Terminology code for interrogation of an implantable pacemaker, cardioverter-defibrillator, or loop recorder and no documented history of AF , atrial flutter, or stroke before their first device interrogation. Kaplan-Meier statistics and Cox proportional hazards models were used to examine the association between black race and the composite outcome of AF or atrial flutter while adjusting for age, sex, and vascular risk factors. Among 47 417 eligible patients, the annual incidence of AF /atrial flutter was 12.2 (95% CI , 11.5-13.1) per 100 person-years among blacks and 17.6 (95% CI , 17.4-17.9) per 100 person-years among non-black beneficiaries. After adjustment for confounders, black beneficiaries faced a lower hazard of AF /atrial flutter than non-black beneficiaries (hazard ratio, 0.75; 95% CI , 0.70-0.80). Despite the lower risk of AF , black patients faced a higher hazard of ischemic stroke (hazard ratio, 1.37; 95% CI , 1.22-1.53). Conclusions Among Medicare beneficiaries with implanted cardiac devices capable of detecting atrial rhythm, black patients had a lower incidence of AF despite a higher burden of vascular risk factors and a higher risk of stroke.

Specialty Classifications of Physicians Who Provide Neurocritical Care in the United States.

BACKGROUND: We sought to characterize the specialty classification of US physicians who provide critical care for neurological/neurosurgical disease. METHODS: Using inpatient claims between 2009 and 2015 from a nationally representative 5% sample of Medicare beneficiaries, we selected hospitalizations for neurological/neurosurgical diseases with potential to result in life-threatening manifestations requiring critical care. Using Current Procedural Terminology® codes, we determined the medical specialty of providers submitting critical care claims, and, using National Provider Identifier numbers, we merged in data from the United Council for Neurologic Subspecialties (UCNS) to determine whether the provider was a UCNS diplomate in neurocritical care. We defined providers with a clinical neuroscience background as neurologists, neurosurgeons, and/or UCNS diplomates in neurocritical care. We defined neurocritical care service as a critical care claim with a qualifying neurological/neurosurgical diagnosis in patients with a relevant primary hospital discharge diagnosis and ≥ 3 total critical care claims, excluding claims from the first day of hospitalization since these were mostly emergency-department claims. Our findings were reported using descriptive statistics with exact confidence intervals (CI). RESULTS: Among 1,952,305 Medicare beneficiaries, we identified 99,937 hospitalizations with at least one claim for neurocritical care. In our primary analysis, neurologists accounted for 28.0% (95% CI, 27.5-28.5%) of claims, neurosurgeons for 3.7% (95% CI, 3.5-3.9%), UCNS-certified neurointensivists for 25.8% (95% CI, 25.3-26.3%), and providers with any clinical neuroscience background for 42.8% (95% CI, 42.2-43.3%). The likelihood of management by physicians with a clinical neuroscience background increased proportionally with patients' county-level socioeconomic status and such providers were 3 times more likely to be based at an academic medical center than other physicians who billed for critical care in our sample (odds ratio, 2.9; 95% CI, 1.1-8.1). CONCLUSIONS: Physicians with a dedicated clinical neuroscience background accounted for less than half of neurocritical care service in US Medicare beneficiaries.

Arterial thromboembolic events preceding the diagnosis of cancer in older persons.

Cancer patients face an increased risk of arterial thromboembolism; however, it is uncertain when this excess risk begins. This study evaluated the risk of arterial thromboembolism before cancer diagnosis. Using the population-based Surveillance Epidemiology and End Results-Medicare linked dataset, we identified 374 331 patients ≥67 years of age with a new primary diagnosis of breast, lung, prostate, colorectal, bladder, uterine, pancreatic, gastric cancer, or non-Hodgkin lymphoma from 2005 through 2013. Cancer patients were individually matched by demographics and comorbidities to Medicare beneficiaries without cancer, who served as controls. Validated diagnosis codes were used to identify arterial thromboembolic events, defined as a composite of myocardial infarction or ischemic stroke. The Mantel-Haenszel estimator was used to compare risks of arterial thromboembolic events between cancer and noncancer groups during 30-day periods in the 360 days before date of cancer diagnosis. From 360 to 151 days before cancer diagnosis, the 30-day interval risks of arterial thromboembolic events were similar between cancer patients and matched controls. From 150 to 1 day before cancer diagnosis, the interval 30-day risks of arterial thromboembolic events were higher in cancer patients vs matched controls, progressively increasing as the cancer diagnosis date approached and peaking during the 30 days immediately before cancer diagnosis, when 2313 (0.62%) cancer patients were diagnosed with an arterial thromboembolic event vs 413 (0.11%) controls (odds ratio, 5.63; 95% confidence interval, 5.07-6.25). In conclusion, the risk of arterial thromboembolic events begins to increase 150 days before the date of cancer diagnosis in older persons and peaks in the 30 days before.