Causal inference in the absence of positivity: The role of overlap weights.

How to analyze data when there is violation of the positivity assumption? Several possible solutions exist in the literature. In this paper, we consider propensity score (PS) methods that are commonly used in observational studies to assess causal treatment effects in the context where the positivity assumption is violated. We focus on and examine four specific alternative solutions to the inverse probability weighting (IPW) trimming and truncation: matching weight (MW), Shannon's entropy weight (EW), overlap weight (OW), and beta weight (BW) estimators. We first specify their target population, the population of patients for whom clinical equipoise, that is, where we have sufficient PS overlap. Then, we establish the nexus among the different corresponding weights (and estimators); this allows us to highlight the shared properties and theoretical implications of these estimators. Finally, we introduce their augmented estimators that take advantage of estimating both the propensity score and outcome regression models to enhance the treatment effect estimators in terms of bias and efficiency. We also elucidate the role of the OW estimator as the flagship of all these methods that target the overlap population. Our analytic results demonstrate that OW, MW, and EW are preferable to IPW and some cases of BW when there is a moderate or extreme (stochastic or structural) violation of the positivity assumption. We then evaluate, compare, and confirm the finite-sample performance of the aforementioned estimators via Monte Carlo simulations. Finally, we illustrate these methods using two real-world data examples marked by violations of the positivity assumption.

Recent Vitamin K Antagonist Use and Intracranial Hemorrhage After Endovascular Thrombectomy for Acute Ischemic Stroke.

Importance: Use of oral vitamin K antagonists (VKAs) may place patients undergoing endovascular thrombectomy (EVT) for acute ischemic stroke caused by large vessel occlusion at increased risk of complications. Objective: To determine the association between recent use of a VKA and outcomes among patients selected to undergo EVT in clinical practice. Design, Setting, and Participants: Retrospective, observational cohort study based on the American Heart Association's Get With the Guidelines-Stroke Program between October 2015 and March 2020. From 594 participating hospitals in the US, 32 715 patients with acute ischemic stroke selected to undergo EVT within 6 hours of time last known to be well were included. Exposure: VKA use within the 7 days prior to hospital arrival. Main Outcome and Measures: The primary end point was symptomatic intracranial hemorrhage (sICH). Secondary end points included life-threatening systemic hemorrhage, another serious complication, any complications of reperfusion therapy, in-hospital mortality, and in-hospital mortality or discharge to hospice. Results: Of 32 715 patients (median age, 72 years; 50.7% female), 3087 (9.4%) had used a VKA (median international normalized ratio [INR], 1.5 [IQR, 1.2-1.9]) and 29 628 had not used a VKA prior to hospital presentation. Overall, prior VKA use was not significantly associated with an increased risk of sICH (211/3087 patients [6.8%] taking a VKA compared with 1904/29 628 patients [6.4%] not taking a VKA; adjusted odds ratio [OR], 1.12 [95% CI, 0.94-1.35]; adjusted risk difference, 0.69% [95% CI, -0.39% to 1.77%]). Among 830 patients taking a VKA with an INR greater than 1.7, sICH risk was significantly higher than in those not taking a VKA (8.3% vs 6.4%; adjusted OR, 1.88 [95% CI, 1.33-2.65]; adjusted risk difference, 4.03% [95% CI, 1.53%-6.53%]), while those with an INR of 1.7 or lower (n = 1585) had no significant difference in the risk of sICH (6.7% vs 6.4%; adjusted OR, 1.24 [95% CI, 0.87-1.76]; adjusted risk difference, 1.13% [95% CI, -0.79% to 3.04%]). Of 5 prespecified secondary end points, none showed a significant difference across VKA-exposed vs VKA-unexposed groups. Conclusions and Relevance: Among patients with acute ischemic stroke selected to receive EVT, VKA use within the preceding 7 days was not associated with a significantly increased risk of sICH overall. However, recent VKA use with a presenting INR greater than 1.7 was associated with a significantly increased risk of sICH compared with no use of anticoagulants.

Racial and Ethnic Differences in Presentation and Outcomes for Patients Hospitalized With COVID-19: Findings From the American Heart Association's COVID-19 Cardiovascular Disease Registry.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has exposed longstanding racial and ethnic inequities in health risks and outcomes in the United States. We aimed to identify racial and ethnic differences in presentation and outcomes for patients hospitalized with COVID-19. METHODS: The American Heart Association COVID-19 Cardiovascular Disease Registry is a retrospective observational registry capturing consecutive patients hospitalized with COVID-19. We present data on the first 7868 patients by race/ethnicity treated at 88 hospitals across the United States between January 17, 2020, and July 22, 2020. The primary outcome was in-hospital mortality. Secondary outcomes included major adverse cardiovascular events (death, myocardial infarction, stroke, heart failure) and COVID-19 cardiorespiratory ordinal severity score (worst to best: death, cardiac arrest, mechanical ventilation with mechanical circulatory support, mechanical ventilation with vasopressors/inotrope support, mechanical ventilation without hemodynamic support, and hospitalization alone. Multivariable logistic regression analyses were performed to assess the relationship between race/ethnicity and each outcome adjusting for differences in sociodemographic, clinical, and presentation features, and accounting for clustering by hospital. RESULTS: Among 7868 patients hospitalized with COVID-19, 33.0% were Hispanic, 25.5% were non-Hispanic Black, 6.3% were Asian, and 35.2% were non-Hispanic White. Hispanic and Black patients were younger than non-Hispanic White and Asian patients and were more likely to be uninsured. Black patients had the highest prevalence of obesity, hypertension, and diabetes. Black patients also had the highest rates of mechanical ventilation (23.2%) and renal replacement therapy (6.6%) but the lowest rates of remdesivir use (6.1%). Overall mortality was 18.4% with 53% of all deaths occurring in Black and Hispanic patients. The adjusted odds ratios for mortality were 0.93 (95% CI, 0.76-1.14) for Black patients, 0.90 (95% CI, 0.73-1.11) for Hispanic patients, and 1.31 (95% CI, 0.96-1.80) for Asian patients compared with non-Hispanic White patients. The median odds ratio across hospitals was 1.99 (95% CI, 1.74-2.48). Results were similar for major adverse cardiovascular events. Asian patients had the highest COVID-19 cardiorespiratory severity at presentation (adjusted odds ratio, 1.48 [95% CI, 1.16-1.90]). CONCLUSIONS: Although in-hospital mortality and major adverse cardiovascular events did not differ by race/ethnicity after adjustment, Black and Hispanic patients bore a greater burden of mortality and morbidity because of their disproportionate representation among COVID-19 hospitalizations.

Sex Differences in Endovascular Therapy for Ischemic Stroke: Results From the Get With The Guidelines-Stroke Registry.

BACKGROUND: In 2015, endovascular therapy (EVT) for large vessel occlusions became standard of care for acute ischemic stroke. Lower utilization of IV alteplase has been reported in women, but whether sex differences in EVT use in the United States exists has not been established. METHODS: We identified all acute ischemic stroke discharges from Get With The Guidelines-Stroke hospitals between 2012 and 2019 who were potentially eligible for EVT, based on National Institutes of Health Stroke Scale score ≥6 and arrival <6 hours, according to 2018 American Heart Association/ASA guidelines. Multivariable regression analyses were used to determine the association between sex and EVT utilization, and outcomes (including mortality, discharge home, functional status) after EVT. Separate analyses were conducted for the 2 time periods: 2012 to 2014, and 2015 to 2019. RESULTS: Of 302 965 patients potentially eligible for EVT, 42 422 (14%) received EVT. Before 2015, EVT treatment rates were 5.3% in women and 6.6% in men. From 2015 to 2019, treatment rates increased in both sexes to 16.7% in women and 18.5% in men. The adjusted odds ratio for EVT in women compared with men was 0.93 (95% CI, 0.87-0.99) before 2015, and 0.98 (95% CI, 0.96-1.01) after 2015. There were no significant sex differences in outcomes except that after 2015, women were less able to ambulate at discharge (adjusted odds ratio, 0.95 [95% CI, 0.95-0.99]) and had lower in-hospital mortality (adjusted odds ratio, 0.93 [95% CI, 0.88-0.99]). CONCLUSIONS: EVT utilization has increased dramatically in both women and men since EVT approval in 2015. Following statistical adjustment, women were less likely to receive EVT initially, but after 2015, women were as likely as men to receive EVT. After EVT, women were more likely to be disabled at discharge but less likely to experience in-hospital death compared with men.

US Surveillance of Acute Ischemic Stroke Patient Characteristics, Care Quality, and Outcomes for 2019.

BACKGROUND: The United States lacks a timely and accurate nationwide surveillance system for acute ischemic stroke (AIS). We use the Get With The Guidelines-Stroke registry to apply poststratification survey weights to generate national assessment of AIS epidemiology, hospital care quality, and in-hospital outcomes. METHODS: Clinical data from the Get With The Guidelines-Stroke registry were weighted using a Bayesian interpolation method anchored to observations from the national inpatient sample. To generate a US stroke forecast for 2019, we linearized time trend estimates from the national inpatient sample to project anticipated AIS hospital volume, distribution, and race/ethnicity characteristics for the year 2019. Primary measures of AIS epidemiology and clinical care included patient and hospital characteristics, stroke severity, vital and laboratory measures, treatment interventions, performance measures, disposition, and clinical outcomes at discharge. RESULTS: We estimate 552 476 patients with AIS were admitted in 2019 to US hospitals. Median age was 71 (interquartile range, 60-81), 48.8% female. Atrial fibrillation was diagnosed in 22.6%, 30.2% had prior stroke/transient ischemic attack, and 36.4% had diabetes. At baseline, 46.4% of patients with AIS were taking antiplatelet agents, 19.2% anticoagulants, and 46.3% cholesterol-reducers. Mortality was 4.4%, and only 52.3% were able to ambulate independently at discharge. Performance nationally on AIS achievement measures were generally higher than 95% for all measures but the use of thrombolytics within 3 hours of early stroke presentations (81.9%). Additional quality measures had lower rates of receipt: dysphagia screening (84.9%), early thrombolytics by 4.5 hours (79.7%), and statin therapy (80.6%). CONCLUSIONS: We provide timely, reliable, and actionable US national AIS surveillance using Bayesian interpolation poststratification weights. These data may facilitate more targeted quality improvement efforts, resource allocation, and national policies to improve AIS care and outcomes.

Association of readmission penalty amount with subsequent 30-day risk standardized readmission and mortality rates among patients hospitalized with heart failure: An analysis of get with the guidelines - heart failure participating centers.

BACKGROUND: The Hospital Readmissions Reduction Program penalizes hospitals with excess 30-day risk-standardized readmission rates (RSRR) for heart failure (HF). The association of financial penalty amount with subsequent short-term clinical outcomes is unknown. METHODS: Patients admitted to American Heart Association Get With The Guidelines-HF registry participating centers from October 1, 2012 through December 1, 2015 who had Medicare-linked data were included. October 2012 hospital-specific penalty amounts were calculated based on diagnosis-related group payments and excess readmission ratios. Adjusted Cox models were created to evaluate the association of penalty amount categories (non-penalized: 0%; low-penalized: >0%-<0.50%; mid-penalized ≥0.50%-<0.99%; high-penalized ≥0.99%) with subsequent 30-day RSRR and risk-standardized mortality rates (RSMR). Trends in post-discharge 30-day RSRR and RSMR from 2012 to 2015 were analyzed across hospitals stratified by penalty amount categories. RESULTS: The present study included 61,329 patients who were admitted across 262 hospitals. Compared with patients admitted to non-penalized hospitals (36.3%), those admitted to increasingly penalized hospitals were more likely to have higher 30-day RSRR (low-penalized [43.9%]: HR, 1.10 [95% CI, 1.04-1.16]; mid-penalized [12.0%]: HR, 1.07 [95% CI, 0.99-1.16]; high-penalized [7.9%]: HR, 1.23 [95% CI, 1.12-1.35]) but not 30-day RSMR. Over time, 30-day RSRR and RSMR did not meaningfully change across penalized versus non-penalized hospitals. CONCLUSIONS: Financial penalties based on 30-day RSRR are not associated with declines in 30-day RSRR or RSMR from 2012 to 2015 among patients hospitalized with HF. Financially penalizing hospitals based on current Hospital Readmissions Reduction Program metrics may not incentivize improvements in short-term clinical outcomes for HF.

Is the affordable care act medicaid expansion associated with receipt of heart failure guideline-directed medical therapy by race and ethnicity?

BACKGROUND: Uninsurance is a known contributor to racial/ethnic health inequities. Insurance is often needed for prescriptions and follow-up appointments. Therefore, we determined whether the Affordable Care Act(ACA) Medicaid Expansion was associated with increased receipt of guideline-directed medical treatment(GDMT) at discharge among patients hospitalized with heart failure(HF) by race/ethnicity. METHODS: Using Get With The Guidelines-HF registry, logistic regression was used to assess odds of receiving GDMT(HF medications; education; follow-up appointment) in early vs non-adopter states before(2012 - 2013) and after ACA Medicaid Expansion(2014 - 2019) within each race/ethnicity, accounting for patient-level covariates and within-hospital clustering. We tested for an interaction(p-int) between GDMT and pre/post Medicaid Expansion time periods. RESULTS: Among 271,606 patients(57.5% early adopter, 42.5% non-adopter), 65.5% were White, 22.8% African American, 8.9% Hispanic, and 2.9% Asian race/ethnicity. Independent of ACA timing, Hispanic patients were more likely to receive all GDMT for residing in early adopter states compared to non-adopter states (P <.0001). In fully-adjusted analyses, ACA Medicaid Expansion was associated with higher odds of receipt of ACEI/ARB/ARNI in Hispanic patients [before ACA:OR 0.40(95%CI:0.13,1.23); after ACA:OR 2.46(1.10,5.51); P-int = .0002], but this occurred in the setting of an immediate decline in prescribing patterns, particularly among non-adopter states, followed by an increase that remained lowest in non-adopter states. The ACA was not associated with receipt of GDMT for other racial/ethnic groups. CONCLUSIONS: Among GWTG-HF hospitals, Hispanic patients were more likely to receive all GDMT if they resided in early adopter states rather than non-adopter states, independent of ACA Medicaid Expansion timing. ACA implementation was only associated with higher odds of receipt of ACEI/ARB/ARNI in Hispanic patients. Additional steps are needed for improved GDMT delivery for all.

Achievement and quality measure attainment in patients hospitalized with atrial fibrillation: Results from The Get With The Guidelines - Atrial Fibrillation (GWTG-AFIB) registry.

BACKGROUND: The Get With The Guidelines - Atrial Fibrillation (GWTG-AFIB) Registry uses achievement and quality measures to improve the care of patients with atrial fibrillation (AF). We sought to evaluate overall and site-level variation in attainment of these measures among sites participating in the GWTG-AFIB Registry. METHODS: From the GWTG-AFIB registry, we included patients with AF admitted between 1/3/2013 and 6/30/2019. We described patient-level attainment and variation in attainment across sites of 6 achievement measures with 1) defect-free scores (percent of patients with all eligible measures attained), and 2) composite opportunity scores (percent of all eligible patient measures attained). We also described attainment of 11 quality measures at the patient-level. RESULTS: Among 80,951 patients hospitalized for AF (age 70±13 years, 47.0% female; CHA2DS2-VASc 3.6±1.8) at 132 sites. Site-level defect-free scores ranged from 4.7% to 85.8% (25th, 50th, 75th percentile: 32.7%, 52.1%, 64.4%). Composite opportunity scores ranged from 39.4% to 97.5% (25th, 50th, 75th: 68.1%, 80.3%, 87.1%). Attainment was notably low for the following quality measures: 1) aldosterone antagonist prescription when ejection fraction ≤35% (29% of those eligible); and 2) avoidance of antiplatelet therapy with OAC in patients without coronary/peripheral artery disease (81% of those eligible). CONCLUSIONS: Despite high overall attainment of care measures across GWTG-AFIB registry sites, large site variation was present with meaningful opportunities to improve AF care beyond OAC prescription, including but not limited to prescription of aldosterone antagonists in those with AF and systolic dysfunction and avoidance of non-indicated adjunctive antiplatelet therapy.

Association of Recent Use of Non-Vitamin K Antagonist Oral Anticoagulants With Intracranial Hemorrhage Among Patients With Acute Ischemic Stroke Treated With Alteplase.

Importance: Current guidelines recommend against use of intravenous alteplase in patients with acute ischemic stroke who are taking non-vitamin K antagonist oral anticoagulants (NOACs). Objective: To evaluate the safety and functional outcomes of intravenous alteplase among patients who were taking NOACs prior to stroke and compare outcomes with patients who were not taking long-term anticoagulants. Design, Setting, and Participants: A retrospective cohort study of 163 038 patients with acute ischemic stroke either taking NOACs or not taking anticoagulants prior to stroke and treated with intravenous alteplase within 4.5 hours of symptom onset at 1752 US hospitals participating in the Get With The Guidelines-Stroke program between April 2015 and March 2020, with complementary data from the Addressing Real-world Anticoagulant Management Issues in Stroke registry. Exposures: Prestroke treatment with NOACs within 7 days prior to alteplase treatment. Main Outcomes and Measures: The primary outcome was symptomatic intracranial hemorrhage occurring within 36 hours after intravenous alteplase administration. There were 4 secondary safety outcomes, including inpatient mortality, and 7 secondary functional outcomes assessed at hospital discharge, including the proportion of patients discharged home. Results: Of 163 038 patients treated with intravenous alteplase (median age, 70 [IQR, 59 to 81] years; 49.1% women), 2207 (1.4%) were taking NOACs and 160 831 (98.6%) were not taking anticoagulants prior to their stroke. Patients taking NOACs were older (median age, 75 [IQR, 64 to 82] years vs 70 [IQR, 58 to 81] years for those not taking anticoagulants), had a higher prevalence of cardiovascular comorbidities, and experienced more severe strokes (median National Institutes of Health Stroke Scale score, 10 [IQR, 5 to 17] vs 7 [IQR, 4 to 14]) (all standardized differences >10). The unadjusted rate of symptomatic intracranial hemorrhage was 3.7% (95% CI, 2.9% to 4.5%) for patients taking NOACs vs 3.2% (95% CI, 3.1% to 3.3%) for patients not taking anticoagulants. After adjusting for baseline clinical factors, the risk of symptomatic intracranial hemorrhage was not significantly different between groups (adjusted odds ratio [OR], 0.88 [95% CI, 0.70 to 1.10]; adjusted risk difference [RD], -0.51% [95% CI, -1.36% to 0.34%]). There were no significant differences in the secondary safety outcomes, including inpatient mortality (6.3% for patients taking NOACs vs 4.9% for patients not taking anticoagulants; adjusted OR, 0.84 [95% CI, 0.69 to 1.01]; adjusted RD, -1.20% [95% CI, -2.39% to -0%]). Of the secondary functional outcomes, 4 of 7 showed significant differences in favor of the NOAC group after adjustment, including the proportion of patients discharged home (45.9% vs 53.6% for patients not taking anticoagulants; adjusted OR, 1.17 [95% CI, 1.06 to 1.29]; adjusted RD, 3.84% [95% CI, 1.46% to 6.22%]). Conclusions and Relevance: Among patients with acute ischemic stroke treated with intravenous alteplase, use of NOACs within the preceding 7 days, compared with no use of anticoagulants, was not associated with a significantly increased risk of intracranial hemorrhage.

Frequency, Characteristics, and Outcomes of Endovascular Thrombectomy in Patients With Stroke Beyond 6 Hours of Onset in US Clinical Practice.

BACKGROUND AND PURPOSE: In 2018, 2 randomized controlled trials showed the benefit of endovascular thrombectomy (EVT) in acute ischemic stroke patients treated 6 to 24 hours from last known well using imaging-guided selection. However, little is known about outcomes in contemporary nontrial settings. We assessed the frequency of EVT and outcomes beyond 6 hours in the US Get With The Guidelines-Stroke clinical registry. METHODS: We analyzed all acute ischemic stroke patients treated with EVT between January 1, 2009 and October, 1, 2018, at Get With The Guidelines-Stroke hospitals in the United States. We assessed trends over time in frequency of EVT beyond 6 hours, compared patient characteristics and outcomes between those treated within versus beyond 6 hours, and evaluated the associations between EVT time and outcomes. RESULTS: We identified 53 702 patients at 697 sites treated with EVT during the study period. Treatment after 6 hours from last known well occurred in 17 720 (33%) of all 53 702 EVT cases (median 4.7 hours, interquartile range, 3.3-7 hours). The proportion of EVT cases treated after 6 hours from last known well varied widely across sites (median 30%, interquartile range, 24%-38%). Compared with patients treated within 6 hours, those treated beyond six hours were younger, less likely to have atrial fibrillation, less likely to arrive by ambulance, had lower stroke severity, were less likely to be anticoagulated, and more likely to be treated at centers with higher EVT volumes. After adjusting for patient and hospital characteristics, patients receiving EVT beyond 6 hours had less favorable in-hospital mortality, ambulation at discharge, and discharge disposition compared to those treated within 6 hours. CONCLUSIONS: EVT is frequently performed for patients with ischemic stroke after 6 hours from last known well, accounting for one-third of cases nationally, and adjusted functional outcomes at discharge are worse in these patients compared to those treated with EVT within 6 hours. Further efforts are needed for optimal EVT outcomes in clinical practice settings.

Antithrombotic Therapy for Stroke Prevention in Patients With Ischemic Stroke With Aspirin Treatment Failure.

BACKGROUND AND PURPOSE: Many older patients presenting with acute ischemic stroke were already taking aspirin before admission. However, the management strategy for patients with aspirin treatment failure has not been fully established. METHODS: We used data from the American Heart Association Get With The Guidelines Stroke Registry to describe discharge antithrombotic treatment patterns among Medicare beneficiaries with ischemic stroke who were taking aspirin before their stroke and were discharged alive from 1734 hospitals in the United States between October 2012 and December 2017. RESULTS: Of 261 634 ischemic stroke survivors, 100 016 (38.2%) were taking aspirin monotherapy before stroke. Among them, 44.4% of patients remained on aspirin monotherapy at discharge (20.9% 81 mg, 18.2% 325 mg, 5.3% other or unknown dose). The next most common therapy choice was dual antiplatelet therapy (24.6%), followed by clopidogrel monotherapy (17.8%). The remaining 13.2% of patients were discharged on either aspirin/dipyridamole, warfarin, or nonvitamin K antagonist oral anticoagulants with or without antiplatelet, or no antithrombotic therapy at all. CONCLUSIONS: Nearly half of patients with ischemic stroke while on preventive therapy with aspirin are discharged on aspirin monotherapy without changing antithrombotic class, while the other half are discharged on clopidogrel monotherapy, dual antiplatelet therapy, or other less common agents. These findings emphasize the need for future research to identify best management strategies for this very common and complex clinical scenario.

Pharmacoepidemiology of Ceftazidime-Avibactam Use: A Retrospective Cohort Analysis of 210 US Hospitals.

BACKGROUND: Ceftazidime-avibactam has in vitro activity against some carbapenem-resistant gram-negative infections (GNIs), and therefore may be a useful alternative to more toxic antibiotics such as colistin. Understanding ceftazidime-avibactam uptake and usage patterns would inform hospital formularies, stewardship, and antibiotic development. METHODS: A retrospective cohort study assessed inpatient encounters in the Vizient database. Ceftazidime-avibactam and colistin administrations were categorized into presumed empiric (3 consecutive days of therapy or less with qualifying exclusions) versus targeted therapy (≥4 consecutive days of therapy) for presumed carbapenem-resistant GNIs. Quarterly percentage change (QPC) using modified Poisson regression and relative change in frequency of targeted ceftazidime-avibactam to colistin encounters was calculated. Factors associated with preferentially receiving targeted ceftazidime-avibactam versus colistin were identified using generalized estimating equations. RESULTS: Between 2015 quarter (q) 1 and 2017q4, ceftazidime-avibactam was administered 21 215 times across 1901 encounters. Inpatient prescriptions for ceftazidime-avibactam increased from 0.44/10 000 hospitalizations in 2015q1 to 7.7/10 000 in 2017q4 (QPC, +11%; 95% CI, 10-13%; P < .01), while conversely colistin prescriptions decreased quarterly by 5% (95% CI, 4-6%; P < .01). Ceftazidime-avibactam therapy was categorized as empiric 25% of the time, targeted 65% of the time, and indeterminate 10% of the time. Patients with chronic kidney disease were twice as likely to receive targeted ceftazidime-avibactam versus colistin (RR, 2.02; 95% CI, 1.82-2.25), whereas those on dialysis were less likely to receive ceftazidime-avibactam than colistin (RR, 0.71; 95% CI, .61-.83). CONCLUSIONS: Since approval in 2015, ceftazidime-avibactam use has grown for presumed carbapenem-resistant GNIs, while colistin has correspondingly declined. Renal function drove the choice between ceftazidime-avibactam and colistin as targeted therapy.

Patient characteristics, care patterns, and outcomes of atrial fibrillation associated hospitalizations in patients with chronic kidney disease and end-stage renal disease.

BACKGROUND: Chronic Kidney Disease (CKD) and end-stage renal disease (ESRD) are associated with poor outcomes in patients with cardiovascular disease. There is a paucity of contemporary data on in-hospital outcomes and care patterns of atrial fibrillation (AF) associated hospitalizations CKD and ESRD. METHODS: Outcomes and care patterns were evaluated in GWTG-AFIB database (Jan 2013-Dec 2018), including in-hospital mortality, use of a rhythm control strategy, and oral anticoagulation (OAC) prescription at discharge among eligible patients. Generalized logistic regression models with generalized estimating equations were used to ascertain differences in outcomes. Hospital-level variation in OAC prescription and rhythm control was also evaluated. RESULTS: Among 50,154 patients from 105 hospitals the median age was 70 years (interquartile range 61-79) and 47.3% were women. The prevalence of CKD was 36.0% while that of ESRD was 1.6%. Among eligible patients, discharge OAC prescription rates were 93.6% for CKD and 89.1% for ESRD. After adjustment, CKD and ESRD were associated with higher in-hospital mortality (odds ratio [OR] 3.08, 95% confidence interval [CI] 1.57-6.03 for ESRD and OR 2.02, 95% CI 1.52-2.67 for CKD), lower odds of OAC prescription at discharge (OR 0.59, 95% CI 0.44-0.79 for ESRD and OR 0.84, 95% CI 0.75-0.94 for CKD) compared with normal renal function. CKD was associated with lower utilization of rhythm control strategy (OR 0.92, 95% CI 0.87-0.98) with no significant difference between ESRD and normal renal function (OR 1.32, 95% CI 0.79-1.11). There was large hospital-level variation in OAC prescription at discharge (MOR 2.34, 95% CI 2.05-2.76) and utilization of a rhythm control strategy (MOR 2.69, 95% CI 2.34-3.21). CONCLUSIONS: CKD/ESRD is associated with higher in-hospital mortality, less frequent rhythm control, and less OAC prescription among patients hospitalized for AF. There is wide hospital-level variation in utilization of a rhythm control strategy and OAC prescription at discharge highlighting potential opportunities to improve care and outcomes for these patients, and better define standards of care in this patient population.

Temporal trends in risk profiles among patients hospitalized for heart failure.

BACKGROUND: Postdischarge mortality following hospitalization for heart failure with reduced ejection fraction (HFrEF) has remained high and unchanged over the past 2 decades, despite effective therapies for HFrEF. We aimed to explore whether these patterns could in part be explained by changes in longitudinal risk profile and HF severity over time. METHODS: Among patients hospitalized for HF in the GWTG-HF registry from January 2005 to December 2018 with available data, we evaluated GWTG-HF and ADHERE risk scores, observing in-hospital mortality per-year. The risk profiles and outcomes were described overall and by subgroups based on ejection fraction (EF), diabetes mellitus (DM), sex, and age. RESULTS: Overall, 335,735 patients were included (50% HFrEF, 46% DM, 48% female, mean age 74 years). In-hospital mortality increased by 2.0% per year from 2005 to 2018. There was no significant change in mean GWTG-HF risk score overall or when stratified by EF groups (P = 0.46 HFrEF, p = 0.26 HF mid-range EF [HFmrEF], and P = 0.72 HF preserved EF [HFpEF]), age, sex, or presence of DM. The observed/expected ratio based on the GWTG-HF risk score was 0.93 (0.91-0.96), 0.83 (0.77-0.90), 0.92 (0.89-95) for HFrEF, HFmrEF, and HFpEF, respectively. Similar findings were seen when risk was assessed using ADHERE risk score. CONCLUSIONS: There were no significant changes in average risk profiles among hospitalized HF patients over the study duration. These data do not support the notion that worsening risk profile explains the lack of improved outcomes despite therapeutic advances, underscoring the importance of aggressive implementation of guideline-recommended therapies and investigation of novel treatments.

Procedure characteristics and outcomes of atrial fibrillation ablation procedures using cryoballoon versus radiofrequency ablation: A report from the GWTG-AFIB registry.

INTRODUCTION: Cryoballoon ablation (CBA) is an alternative to radiofrequency ablation (RFA) for ablation of atrial fibrillation (AF) and real-world comparisons of this strategy are lacking. As such, we sought to compare patient and periprocedural characteristics and outcomes of CBA versus RFA in the Get With the Guidelines AFIB Registry. METHODS: Categorical variables were compared via the χ2 test and continuous variables were compared via the Wilcoxon rank-sum test. Adjusted analyses were performed using overlap weighting of propensity scores. RESULTS: A total of 5247 (1465 CBA, 3782 RFA) ablation procedures were reported from 33 sites. Those undergoing CBA more often had paroxysmal AF (60.0% vs. 48.8%) and no prior AF ablation (87.5% vs. 73.8%). CHA2 DS2 -VASc scores were similar. Among de novo ablations, most ablations involved intracardiac echocardiography and electroanatomic mapping, but both were less common with CBA (87.3% vs. 93.9%, p < .0001, and 87.7% vs. 94.6%, p < .0001, respectively). CBA was associated with shorter procedures (129 vs. 179 min, p < .0001), increased fluoroscopy use (19 vs. 11 min, p < .0001), and similar ablation times (27 vs. 35 min, p = .15). Nonpulmonary vein ablation was common with CBA: roof line 38.6%, floor line 20.4%, cavotricuspid isthmus 27.7%. RFA was associated with more total complications compared to CBA (5.4% vs. 2.3%, p < .0001), due to more volume overload and "other" events, although phrenic nerve injury was more common with CBA (0.9% vs 0.1%, p = .0001). In the adjusted model, any complication was less common among CBA cases (odds ratio, 0.45; confidence interval, 0.25-0.79, p = .0056). CONCLUSION: CBA was associated with fewer complications, and shorter procedure times, and greater fluoroscopy times, compared to RFA. Nonpulmonary vein ablation and electroanatomic mapping system use was common with CBA.

Profile of Patients Hospitalized for Heart Failure Who Leave Against Medical Advice.

BACKGROUND: There is a paucity of information on patients hospitalized with heart failure (HF) who leave against medical advice (AMA). We sought to identify patient and hospital characteristics and outcomes of patients with HF who left AMA compared with those conventionally discharged to home. METHODS AND RESULTS: Using the Get With The Guidelines-Heart Failure registry, data were analyzed from January 2010 to June 2019. In addition, outcomes were examined from a subset of hospitalizations with Medicare-linked claims between January 2010 and November 2015. The fully eligible population included 561,823 patients and the Medicare-linked subset included 74,502 patients. In total, 8747 patients (1.56%) left AMA. The proportion of patients leaving AMA increased from 1.1% to 2.1% over the years of study. Patients leaving a HF hospitalization AMA, compared with patients conventionally discharged to home, were more likely younger, minorities, Medicaid covered, or uninsured. The Medicare-linked subset of patients who left AMA had substantially higher 30-day and 12-month readmission rates and higher mortality at each assessment point over 12 months compared with patients who were conventionally discharged to home. After risk adjustments, the hazard ratio of mortality in the Medicare-linked subset AMA group compared with the conventionally discharged to home group was 1.25 (95% confidence interval, 1.03-1.51; P = .005). CONCLUSIONS: One in 64 hospitalized patients with HF left AMA. An AMA discharge status was associated with higher risk for adverse 30-day and 12-month outcomes compared with being conventionally discharged home. Strategies that identify patients at risk of leaving AMA and policies to direct interventional strategies are warranted.

Oral Anticoagulation and Adverse Outcomes after Ischemic Stroke in Heart Failure Patients without Atrial Fibrillation.

BACKGROUND: The safety and effectiveness of oral anticoagulation (OAC) after an ischemic stroke in older patients with heart failure (HF) without atrial fibrillation remains uncertain. METHODS: Utilizing Get With The Guidelines Stroke national clinical registry data linked to Medicare claims from 2009-2014, we assessed the outcomes of eligible patients with a history of HF who were initiated on OAC during a hospitalization for an acute ischemic stroke. The cumulative incidences of adverse events were calculated using Kaplan-Meier curves and adjusted Cox proportional hazard ratios were compared between patients discharged on or off OAC. RESULTS: A total of 8,261 patients from 1,370 sites were discharged alive after an acute ischemic stroke and met eligibility criteria. Of those, 747 (9.0%) were initiated on OAC.  Patients on OAC were younger (77.2±8.0 vs. 80.5±8.9 years, p<0.01). After adjustment for clinical covariates, the likelihood of 1 year mortality was higher in those on OAC (aHR: 1.22, 95% CI 1.05-1.41, p<0.01), while no significant differences were noted for ICH (aHR: 1.34, 95% CI 0.69-2.59, p=0.38) and recurrent ischemic stroke (aHR: 0.78, 95% CI 0.54-1.15, p = 0.21).  The likelihood of all-cause bleeding (aHR: 1.59, 95% CI 1.29-1.96, p<0.01) and all-cause re-hospitalization (aHR: 1.14, 95% CI 1.02-1.27, p = 0.02) was higher for those on OAC. CONCLUSION: Initiation of OAC after an ischemic stroke in older patients with HF in the absence of atrial fibrillation is associated with death, bleeding and re-hospitalization without an associated reduction in recurrent ischemic stroke. If validated, these findings raise caution for prescribing OAC to such patients.

National surveillance of stroke quality of care and outcomes by applying post-stratification survey weights on the Get With The Guidelines-Stroke patient registry.

BACKGROUND: The U.S. lacks a stroke surveillance system. This study develops a method to transform an existing registry into a nationally representative database to evaluate acute ischemic stroke care quality. METHODS: Two statistical approaches are used to develop post-stratification weights for the Get With The Guidelines-Stroke registry by anchoring population estimates to the National Inpatient Sample. Post-stratification survey weights are estimated using a raking procedure and Bayesian interpolation methods. Weighting methods are adjusted to limit the dispersion of weights and make reasonable epidemiologic estimates of patient characteristics, quality of hospital care, and clinical outcomes. Standardized differences in national estimates are reported between the two post-stratification methods for anchored and non-anchored patient characteristics to evaluate estimation quality. Primary measures evaluated are patient and hospital characteristics, stroke severity, vital and laboratory measures, disposition, and clinical outcomes at discharge. RESULTS: A total of 1,388,296 acute ischemic strokes occurred between 2012 and 2014. Raking and Bayesian estimates of clinical data not available in administrative data are estimated within 5 to 10% of margin for expected values. Median weight for the raking method is 1.386 and the weights at the 99th percentile is 6.881 with a maximum weight of 30.775. Median Bayesian weight is 1.329 and the 99th percentile weights is 11.201 with a maximum weight of 515.689. CONCLUSIONS: Leveraging existing databases with patient registries to develop post-stratification weights is a reliable approach to estimate acute ischemic stroke epidemiology and monitoring for stroke quality of care nationally. These methods may be applied to other diseases or settings to better monitor population health.

Adherence to Guideline-Directed Stroke Prevention Therapy for Atrial Fibrillation Is Achievable.

BACKGROUND: Efforts to improve prescription of oral anticoagulation (OAC) drugs in patients with atrial fibrillation have had limited success in improving guideline adherence. METHODS: We evaluated adherence to the American College of Cardiology/American Heart Association performance measures for OAC in eligible patients with a CHA2DS2-VASc score ≥2 and trends in prescription over time in the American Heart Association's Get With The Guidelines-AFIB (atrial fibrillation) registry. Adjusted associations with in-hospital outcomes were also determined. The cohort included 33 235 patients with a CHA2DS2-VASc score ≥2 who were admitted for atrial fibrillation and were enrolled at 115 sites between January 1, 2013, and September 31, 2017. RESULTS: The median (25th, 75th percentile) age was 73 years (65, 81 years); 51% were female; and the median (25th, 75th percentile) CHA2DS2-VASc score was 4 (3, 5). At admission, 16 206 (59.5%) of 27 221 patients with a previous diagnosis of atrial fibrillation were taking OAC agents, and OAC drug use at admission was associated with a lower adjusted odds of in-hospital ischemic stroke (odds ratio, 0.38; 95% CI, 0.24-0.59; P<0.0001). At discharge, prescription of OAC in eligible patients (no contraindications) was 93.5% (n=25 499 of 27 270). In a sensitivity analysis, when excluding only strict contraindications (4.6%, n=1497 of 32 806), OAC prescription at discharge was 80.3%. OAC prescription at discharge was higher in those aged ≤75 years, men, those with heart failure, those with previous atrial fibrillation ablation, and those with rhythm control ( P<0.0001 for all). OAC use was lowest in Hispanic patients (90.2%, P<0.0001). Prescription of OAC at discharge in eligible patients improved over time from 79.9% to 96.6% ( P<0.0001). CONCLUSIONS: Among hospitals participating in the GWTG-AFIB quality improvement program, OAC prescription at discharge in eligible guideline-indicated patients increased significantly and improved consistently over time. These data confirm that high-level adherence to guideline-recommended stroke prevention is achievable.

Outcomes and cost among Medicare beneficiaries hospitalized for heart failure assigned to accountable care organizations.

Little is known about the impact of accountable care organizations (ACO) on hospitalized heart failure (HF) patients, a high-cost and high-risk population. OBJECTIVE: We linked Medicare fee-for-service claims from 2013 to 2015 with data from American Heart Association Get With The Guidelines-HF registry to compare HF care, post-discharge outcomes, and total annual Medicare spending by ACO status at discharge. METHODS: Using adjusted Cox models and accounting for competing risks of death, we compared all-cause mortality and readmission at 1 year by ACO status with reporting of hazard ratios (HR) and 99% confidence intervals (CI). RESULTS: The study included 45,259 HF patients from 300 hospitals, with 21.1% assigned to an ACO. Patient characteristics were similar between the two groups with a few exceptions. The ACO patients lived in geographic areas with higher median income ($54400 [IQR $48600-65900] vs $52300 [$45900-61200], P < .0001). Compliance with four HF-specific quality measures was modestly higher in the ACO group (80% vs 76%, P < .0001). In adjusted analysis, ACO status was associated with similar all-cause readmission (HR: 1.03; 99% CI: 0.99, 1.07) but lower risk of 1-year mortality (HR: 0.85; 99% CI: 0.85, 0.90) compared with non-ACO status. Median Medicare spending in the calendar year of hospitalization was similar (ACO $42,737 [IQR $23,011-72,667] vs non-ACO $42,586 [$22,896-72,518], P = 0.06). CONCLUSIONS: Among Medicare patients hospitalized for HF, participation in an ACO was associated with similar rates of all-cause readmission and no associated cost reductions compared with non-ACO status. There was a lower risk of 1-year mortality associated with ACO participation, which warrants further evaluation.