Effect of Mavacamten in Women Compared With Men With Obstructive Hypertrophic Cardiomyopathy: Insights From EXPLORER-HCM.

BACKGROUND: Compared with men, women with hypertrophic cardiomyopathy (HCM) have a higher incidence of heart failure and worse outcomes. We investigated baseline clinical and echocardiographic characteristics and response to mavacamten among women compared with men in the EXPLORER-HCM study (Clinical Study to Evaluate Mavacamten [MYK-461] in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy). METHODS: A prespecified post hoc analysis of sex from the blinded, randomized EXPLORER-HCM trial of mavacamten versus placebo in symptomatic patients with obstructive HCM was performed. Baseline characteristics were compared with t tests for continuous variables (expressed as mean values) and χ2 tests for categorical variables. Prespecified primary, secondary, and exploratory end points and echocardiographic measurements from baseline to end of treatment (week 30) were analyzed with ANCOVA for continuous end points and a generalized linear model with binomial distribution for binary end points, with adjustment for each outcome's baseline value, New York Heart Association class, ß-blocker use, and ergometer type. RESULTS: At baseline, women (n=102) were older (62 years versus 56 years; P<0.0001), had lower peak oxygen consumption (16.7 mL·kg-1·min-1 versus 21.3 mL·kg-1·min-1; P<0.0001), were more likely to be assigned New York Heart Association class III (42% versus 17%; P<0.0001), had worse health status (Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score 64 versus 75; P<0.0001), and had higher baseline plasma NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels (1704 ng/L versus 990 ng/L; P=0.004) than men (n=149). After 30 weeks of mavacamten treatment, similar improvements were observed in women and men in the primary composite end point (percentage difference on mavacamten versus placebo, 22% versus 19%, respectively; P=0.759) and in the secondary end points of change in postexercise left ventricular outflow tract gradient (-42.4 mm Hg versus -33.6 mm Hg; P=0.348), change in peak oxygen consumption (1.2 mL·kg-1·min-1 versus 1.6 mL·kg-1·min-1; P=0.633), and percentage achieving ≥1 New York Heart Association class improvement (41% versus 28%; P=0.254). However, women had greater improvement in health status (Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score 14.8 versus 6.1; P=0.026) and in the exploratory end point of NT-proBNP levels (-1322 ng/L versus -649 ng/L; P=0.0008). CONCLUSIONS: Although at baseline women with symptomatic obstructive HCM enrolled in EXPLORER-HCM were older and had worse heart failure and health status than men, treatment with mavacamten resulted in similar improvements in the primary and most secondary EXPLORER-HCM end points and greater improvements in health status and NT-proBNP. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03470545.

Graft Failure After Coronary Artery Bypass Grafting and Its Association With Patient Characteristics and Clinical Events: A Pooled Individual Patient Data Analysis of Clinical Trials With Imaging Follow-Up.

BACKGROUND: Graft patency is the postulated mechanism for the benefits of coronary artery bypass grafting (CABG). However, systematic graft imaging assessment after CABG is rare, and there is a lack of contemporary data on the factors associated with graft failure and on the association between graft failure and clinical events after CABG. METHODS: We pooled individual patient data from randomized clinical trials with systematic CABG graft imaging to assess the incidence of graft failure and its association with clinical risk factors. The primary outcome was the composite of myocardial infarction or repeat revascularization occurring after CABG and before imaging. A 2-stage meta-analytic approach was used to evaluate the association between graft failure and the primary outcome. We also assessed the association between graft failure and myocardial infarction, repeat revascularization, or all-cause death occurring after imaging. RESULTS: Seven trials were included comprising 4413 patients (mean age, 64.4±9.1 years; 777 [17.6%] women; 3636 [82.4%] men) and 13 163 grafts (8740 saphenous vein grafts and 4423 arterial grafts). The median time to imaging was 1.02 years (interquartile range [IQR], 1.00-1.03). Graft failure occurred in 1487 (33.7%) patients and in 2190 (16.6%) grafts. Age (adjusted odds ratio [aOR], 1.08 [per 10-year increment] [95% CI, 1.01-1.15]; P=0.03), female sex (aOR, 1.27 [95% CI, 1.08-1.50]; P=0.004), and smoking (aOR, 1.20 [95% CI, 1.04-1.38]; P=0.01) were independently associated with graft failure, whereas statins were associated with a protective effect (aOR, 0.74 [95% CI, 0.63-0.88]; P<0.001). Graft failure was associated with an increased risk of myocardial infarction or repeat revascularization occurring between CABG and imaging assessment (8.0% in patients with graft failure versus 1.7% in patients without graft failure; aOR, 3.98 [95% CI, 3.54-4.47]; P<0.001). Graft failure was also associated with an increased risk of myocardial infarction or repeat revascularization occurring after imaging (7.8% versus 2.0%; aOR, 2.59 [95% CI, 1.86-3.62]; P<0.001). All-cause death after imaging occurred more frequently in patients with graft failure compared with patients without graft failure (11.0% versus 2.1%; aOR, 2.79 [95% CI, 2.01-3.89]; P<0.001). CONCLUSIONS: In contemporary practice, graft failure remains common among patients undergoing CABG and is strongly associated with adverse cardiac events.

Trans-Balance: Reducing demographic disparity for prediction models in the presence of class imbalance.

INTRODUCTION: Risk prediction, including early disease detection, prevention, and intervention, is essential to precision medicine. However, systematic bias in risk estimation caused by heterogeneity across different demographic groups can lead to inappropriate or misinformed treatment decisions. In addition, low incidence (class-imbalance) outcomes negatively impact the classification performance of many standard learning algorithms which further exacerbates the racial disparity issues. Therefore, it is crucial to improve the performance of statistical and machine learning models in underrepresented populations in the presence of heavy class imbalance. METHOD: To address demographic disparity in the presence of class imbalance, we develop a novel framework, Trans-Balance, by leveraging recent advances in imbalance learning, transfer learning, and federated learning. We consider a practical setting where data from multiple sites are stored locally under privacy constraints. RESULTS: We show that the proposed Trans-Balance framework improves upon existing approaches by explicitly accounting for heterogeneity across demographic subgroups and cohorts. We demonstrate the feasibility and validity of our methods through numerical experiments and a real application to a multi-cohort study with data from participants of four large, NIH-funded cohorts for stroke risk prediction. CONCLUSION: Our findings indicate that the Trans-Balance approach significantly improves predictive performance, especially in scenarios marked by severe class imbalance and demographic disparity. Given its versatility and effectiveness, Trans-Balance offers a valuable contribution to enhancing risk prediction in biomedical research and related fields.

Predictive Utility of a Validated Polygenic Risk Score for Long-Term Risk of Coronary Heart Disease in Young and Middle-Aged Adults.

BACKGROUND: Understanding the predictive utility of previously derived polygenic risk scores (PRSs) for long-term risk of coronary heart disease (CHD) and its additive value beyond traditional risk factors can inform prevention strategies. METHODS: Data from adults 20 to 59 years of age who were free of CHD from the FOS (Framingham Offspring Study) and the ARIC (Atherosclerosis Risk in Communities) study were analyzed. Because the PRS was derived from samples of predominantly European ancestry, individuals who self-reported White race were included. The sample was stratified by age and cohort: young (FOS, 20-39 years [median, 30 years] of age), early midlife (FOS, 40-59 years [median, 43] years of age), and late midlife (ARIC, 45-59 years [median, 52 years] of age). Two previously derived and validated prediction tools were applied: (1) a 30-year traditional risk factor score and (2) a genome-wide PRS comprising >6 million genetic variants. Hazard ratios for the association between each risk estimate and incident CHD were calculated. Predicted and observed rates of CHD were compared to assess discrimination for each model individually and together with the optimism-corrected C index (95% CI). RESULTS: Among 9757 participants, both the traditional risk factor score (hazard ratio per 1 SD, 2.60 [95% CI, 2.08-3.27], 2.09 [95% CI, 1.83-2.40], and 2.11 [95% CI, 1.96-2.28]) and the PRS (hazard ratio, 1.98 [95% CI, 1.70-2.30], 1.64 [95% CI, 1.47-1.84], and 1.22 [95% CI, 1.15-1.30]) were significantly associated with incident CHD in young, early midlife, and late midlife, respectively. Discrimination was similar or better for the traditional risk factor score (C index, 0.74 [95% CI, 0.70-0.78], 0.70 [95% CI, 0.67-0.72], and 0.72 [95% CI, 0.70-0.73]) compared with an age- and sex-adjusted PRS (0.73 [95% CI, 0.69-0.78], 0.66 [95% CI, 0.62-0.69], and 0.66 [95% CI, 0.64-0.67]) in young, early-midlife, and late-midlife participants, respectively. The ΔC index when PRS was added to the traditional risk factor score was 0.03 (95% CI, 0.001-0.05), 0.02 (95% CI, -0.002 to 0.037), and 0.002 (95% CI, -0.002 to 0.006) in young, early-midlife, and late-midlife participants, respectively. CONCLUSIONS: Despite a statistically significant association between PRS and 30-year risk of CHD, the C statistic improved only marginally with the addition of PRS to the traditional risk factor model among young adults and did not improve among midlife adults. PRS, an immutable factor that cannot be directly intervened on, has minimal clinical utility for long-term CHD prediction when added to a traditional risk factor model.

Heart rate and death and hospitalization for heart failure in patients with persistent or permanent atrial fibrillation: Insights from the ARISTOTLE trial.

Rate control is fundamental in the treatment of patients with atrial fibrillation (AF). The independent association of heart rate with outcomes and range of heart rate associated with best outcomes remains uncertain. We assessed the relationship between heart rate and clinical outcomes in patients with persistent or permanent AF enrolled in the randomized, double-blind ARISTOTLE trial. In patients with persistent or permanent AF, a faster heart rate is associated with a modest, but statistically significant increase in death and heart failure hospitalizations. TRIAL REGISTRATION: ClinicalTrials.gov (NCT00412984).

Morbidity and Mortality Associated With Heart Failure in Acute Coronary Syndrome: A Pooled Analysis of 4 Clinical Trials.

BACKGROUND: Heart failure (HF) may complicate acute coronary syndrome (ACS) and is associated with a high burden of short- and long-term morbidity and mortality. Only limited data regarding future ischemic events and rehospitalization are available for patients who suffer HF before or during ACS. METHODS: A secondary analysis of 4 large ACS trials (PLATO, APPRAISE-2, TRACER, and TRILOGY ACS) using Cox proportional hazards models was performed to investigate the association of HF status (no HF, chronic HF, de novo HF) at presentation for ACS with all-cause and cardiovascular death, major adverse cardiovascular event (MACE ), myocardial infarction, stroke, and hospitalization for heart failure (HHF) by 1 year. Cumulative incidence plots are presented at 30 days and 1 year. RESULTS: A total of 11.1% of the 47,474 patients presenting with ACS presented with evidence of acute HF, 55.0% of whom presented with de novo HF. Patients with chronic HF presented with evidence of acute HF at a higher rate than those with no previous HF (40.3% vs 6.9%). Compared to those without HF, those with chronic and de novo HF had higher rates of all-cause mortality (adjusted hazard ratio [aHR] 2.01, 95% confidence interval [CI] 1.72-2.34 and aHR 1.47, 95% CI1.15-1.88, respectively), MACE (aHR 1.47, 95% CI1.31-1-.66 and aHR 1.38, 95% CI1.12-1.69), and HHF (aHR 2.29, 95% CI2.02-2.61 and aHR 1.48, 95% CI 1.20-1.82) at 1 year. CONCLUSION: In this large cohort of patients with ACS, both prior and de novo HF complicating ACS were associated with significantly higher risk-adjusted rates of death, ischemic events and HHF at 30 days and 1 year. Further studies examining the association between HF and outcomes in this high-risk population are warranted, especially given the advent of more contemporary HF therapies.

Alirocumab after acute coronary syndrome in patients with a history of heart failure.

AIMS: Patients with heart failure (HF) have not been shown to benefit from statins. In a post hoc analysis, we evaluated outcomes in ODYSSEY OUTCOMES in patients with vs. without a history of HF randomized to the proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor alirocumab or placebo. METHODS AND RESULTS: Among 18 924 patients with recent acute coronary syndrome (ACS) receiving intensive or maximum-tolerated statin treatment, the primary outcome of major adverse cardiovascular events (MACE) was compared in patients with or without a history of HF. The pre-specified secondary outcome of hospitalization for HF was also analysed. Overall, 2815 (14.9%) patients had a history of HF. Alirocumab reduced low-density lipoprotein cholesterol and lipoprotein(a) similarly in patients with or without HF. Overall, alirocumab reduced MACE compared with placebo [hazard ratio (HR): 0.85; 95% confidence interval (CI): 0.78-0.93; P = 0.0001]. This effect was observed among patients without a history of HF (HR: 0.78; 95% CI: 0.70-0.86; P < 0.0001), but not in those with a history of HF (HR: 1.17; 95% CI: 0.97-1.40; P = 0.10) (Pinteraction = 0.0001). Alirocumab did not reduce hospitalization for HF, overall or in patients with or without prior HF. CONCLUSION: Alirocumab reduced MACE in patients without a history of HF but not in patients with a history of HF. Alirocumab did not reduce hospitalizations for HF in either group. Patients with a history of HF are a high-risk group that does not appear to benefit from PCSK9 inhibition after ACS.

Predictive Accuracy of Stroke Risk Prediction Models Across Black and White Race, Sex, and Age Groups.

Importance: Stroke is the fifth-highest cause of death in the US and a leading cause of serious long-term disability with particularly high risk in Black individuals. Quality risk prediction algorithms, free of bias, are key for comprehensive prevention strategies. Objective: To compare the performance of stroke-specific algorithms with pooled cohort equations developed for atherosclerotic cardiovascular disease for the prediction of new-onset stroke across different subgroups (race, sex, and age) and to determine the added value of novel machine learning techniques. Design, Setting, and Participants: Retrospective cohort study on combined and harmonized data from Black and White participants of the Framingham Offspring, Atherosclerosis Risk in Communities (ARIC), Multi-Ethnic Study for Atherosclerosis (MESA), and Reasons for Geographical and Racial Differences in Stroke (REGARDS) studies (1983-2019) conducted in the US. The 62 482 participants included at baseline were at least 45 years of age and free of stroke or transient ischemic attack. Exposures: Published stroke-specific algorithms from Framingham and REGARDS (based on self-reported risk factors) as well as pooled cohort equations for atherosclerotic cardiovascular disease plus 2 newly developed machine learning algorithms. Main Outcomes and Measures: Models were designed to estimate the 10-year risk of new-onset stroke (ischemic or hemorrhagic). Discrimination concordance index (C index) and calibration ratios of expected vs observed event rates were assessed at 10 years. Analyses were conducted by race, sex, and age groups. Results: The combined study sample included 62 482 participants (median age, 61 years, 54% women, and 29% Black individuals). Discrimination C indexes were not significantly different for the 2 stroke-specific models (Framingham stroke, 0.72; 95% CI, 0.72-073; REGARDS self-report, 0.73; 95% CI, 0.72-0.74) vs the pooled cohort equations (0.72; 95% CI, 0.71-0.73): differences 0.01 or less (P values >.05) in the combined sample. Significant differences in discrimination were observed by race: the C indexes were 0.76 for all 3 models in White vs 0.69 in Black women (all P values <.001) and between 0.71 and 0.72 in White men and between 0.64 and 0.66 in Black men (all P values ≤.001). When stratified by age, model discrimination was better for younger (<60 years) vs older (≥60 years) adults for both Black and White individuals. The ratios of observed to expected 10-year stroke rates were closest to 1 for the REGARDS self-report model (1.05; 95% CI, 1.00-1.09) and indicated risk overestimation for Framingham stroke (0.86; 95% CI, 0.82-0.89) and pooled cohort equations (0.74; 95% CI, 0.71-0.77). Performance did not significantly improve when novel machine learning algorithms were applied. Conclusions and Relevance: In this analysis of Black and White individuals without stroke or transient ischemic attack among 4 US cohorts, existing stroke-specific risk prediction models and novel machine learning techniques did not significantly improve discriminative accuracy for new-onset stroke compared with the pooled cohort equations, and the REGARDS self-report model had the best calibration. All algorithms exhibited worse discrimination in Black individuals than in White individuals, indicating the need to expand the pool of risk factors and improve modeling techniques to address observed racial disparities and improve model performance.

Apixaban or Vitamin K Antagonists and Aspirin or Placebo According to Kidney Function in Patients With Atrial Fibrillation After Acute Coronary Syndrome or Percutaneous Coronary Intervention: Insights From the AUGUSTUS Trial.

BACKGROUND: In the AUGUSTUS trial (An Open-Label, 2×2 Factorial, Randomized Controlled, Clinical Trial to Evaluate the Safety of Apixaban Versus Vitamin K Antagonist and Aspirin Versus Aspirin Placebo in Patients With Atrial Fibrillation and Acute Coronary Syndrome or Percutaneous Coronary Intervention), apixaban resulted in less bleeding and fewer hospitalizations than vitamin K antagonists, and aspirin caused more bleeding than placebo in patients with atrial fibrillation and acute coronary syndrome or percutaneous coronary intervention treated with a P2Y12 inhibitor. We evaluated the risk-benefit balance of antithrombotic therapy according to kidney function. METHODS: In 4456 patients, the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) formula was used to calculate baseline estimated glomerular filtration rate (eGFR). The effect of apixaban versus vitamin K antagonists and aspirin versus placebo was assessed across kidney function categories by using Cox models. The primary outcome was International Society on Thrombosis and Haemostasis major or clinically relevant nonmajor bleeding. Secondary outcomes included death or hospitalization and ischemic events (death, stroke, myocardial infarction, stent thrombosis [definite or probable], or urgent revascularization). Creatinine clearance <30 mL/min was an exclusion criterion in the AUGUSTUS trial. RESULTS: Overall, 30%, 52%, and 19% had an eGFR of >80, >50 to 80, and 30 to 50 mL·min-1·1.73 m-2, respectively. At the 6-month follow-up, a total of 543 primary outcomes of bleeding, 1125 death or hospitalizations, and 282 ischemic events occurred. Compared with vitamin K antagonists, patients assigned apixaban had lower rates for all 3 outcomes across most eGFR categories without significant interaction. The absolute risk reduction with apixaban was most pronounced in those with an eGFR of 30 to 50 mL·min-1·1.73 m-2 for bleeding events with rates of 13.1% versus 21.3% (hazard ratio, 0.59; 95% CI, 0.41-0.84). Patients assigned aspirin had a higher risk of bleeding in all eGFR categories with an even greater increase among those with eGFR >80 mL·min-1·1.73 m-2: 16.6% versus 5.6% (hazard ratio, 3.22; 95% CI, 2.19-4.74; P for interaction=0.007). The risk of death or hospitalization and ischemic events were comparable to aspirin and placebo across eGFR categories with hazard ratios ranging from 0.97 (95% CI, 0.76-1.23) to 1.28 (95% CI, 1.02-1.59) and from 0.75 (95% CI, 0.48-1.17) to 1.34 (95% CI, 0.81-2.22), respectively. CONCLUSIONS: The safety and efficacy of apixaban was consistent irrespective of kidney function, compared with warfarin, and in accordance with the overall trial results. The risk of bleeding with aspirin was consistently higher across all kidney function categories. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02415400.

Apixaban Versus Warfarin in Patients With Atrial Fibrillation and Advanced Chronic Kidney Disease.

BACKGROUND: Compared with the general population, patients with advanced chronic kidney disease have a >10-fold higher burden of atrial fibrillation. Limited data are available guiding the use of nonvitamin K antagonist oral anticoagulants in this population. METHODS: We compared the safety of apixaban with warfarin in 269 patients with atrial fibrillation and advanced chronic kidney disease (defined as creatinine clearance [CrCl] 25 to 30 mL/min) enrolled in the ARISTOTLE trial (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation). Cox proportional models were used to estimate hazard ratios for major bleeding and major or clinically relevant nonmajor bleeding. We characterized the pharmacokinetic profile of apixaban by assessing differences in exposure using nonlinear mixed effects models. RESULTS: Among patients with CrCl 25 to 30 mL/min, apixaban caused less major bleeding (hazard ratio, 0.34 [95% CI, 0.14-0.80]) and major or clinically relevant nonmajor bleeding (hazard ratio, 0.35 [95% CI, 0.17-0.72]) compared with warfarin. Patients with CrCl 25 to 30 mL/min randomized to apixaban demonstrated a trend toward lower rates of major bleeding when compared with those with CrCl >30 mL/min (P interaction=0.08) and major or clinically relevant nonmajor bleeding (P interaction=0.05). Median daily steady-state areas under the curve for apixaban 5 mg twice daily were 5512 ng/(mL·h) and 3406 ng/(mL·h) for patients with CrCl 25 to 30 mL/min or >30 mL/min, respectively. For apixaban 2.5 mg twice daily, the median exposure was 2780 ng/(mL·h) for patients with CrCl 25 to 30 mL/min. The area under the curve values for patients with CrCl 25 to 30 mL/min fell within the ranges demonstrated for patients with CrCl >30 mL/min. CONCLUSIONS: Among patients with atrial fibrillation and CrCl 25 to 30 mL/min, apixaban caused less bleeding than warfarin, with even greater reductions in bleeding than in patients with CrCl >30 mL/min. We observed substantial overlap in the range of exposure to apixaban 5 mg twice daily for patients with or without advanced chronic kidney disease, supporting conventional dosing in patients with CrCl 25 to 30 mL/min. Randomized, controlled studies evaluating the safety and efficacy of apixaban are urgently needed in patients with advanced chronic kidney disease, including those receiving dialysis. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00412984.

Patients With Atrial Fibrillation Taking Nonsteroidal Anti-Inflammatory Drugs and Oral Anticoagulants in the ARISTOTLE Trial.

BACKGROUND: The use of nonsteroidal anti-inflammatory drugs (NSAIDs) with oral anticoagulants has been associated with an increased risk of bleeding. We investigated the risk of bleeding and major cardiovascular outcomes in patients with atrial fibrillation taking NSAIDs and apixaban or warfarin. METHODS: The ARISTOTLE trial (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation; n=18 201) compared apixaban with warfarin in patients with atrial fibrillation at an increased risk of stroke. Patients in ARISTOTLE without severe renal (creatine clearance ≤30 mL/min) or liver disease were included in this analysis (n=17 423). NSAID use at baseline, NSAID use during the trial (incident NSAID use), and never users were described. The primary outcome was major bleeding. Secondary outcomes included clinically relevant nonmajor bleeding, gastrointestinal bleeding, heart failure hospitalization, stroke or systemic embolism, and all-cause mortality. NSAID use during the trial, and the interaction between randomized treatment, was analyzed using time-dependent Cox proportional hazards models. RESULTS: Those with baseline NSAID use (n=832 [4.8%]), incident NSAID use (n=2185 [13.2%]), and never users were similar in median age (age [25th, 75th]; 70 [64, 77] versus 70 [63, 75] versus 70 [62, 76]). Those with NSAID use at baseline and incident NSAID use were more likely to have a history of bleeding than never users (24.5% versus 21.0% versus 15.6%, respectively). During a median follow-up (25th, 75th) of 1.8 (1.4, 2.3) years and when excluding those taking NSAID at baseline, we found that incident NSAID use was associated with an increased risk of major bleeding (hazard ratio [HR], 1.61 [95% CI, 1.11-2.33]) and clinically relevant nonmajor bleeding (HR, 1.70 [95% CI, 1.16-2.48]), but not gastrointestinal bleeding. No significant interaction was observed between NSAID use and randomized treatment for any outcome. CONCLUSIONS: A substantial number of patients in the ARISTOTLE trial took NSAIDs. Incident NSAID use was associated with major and clinically relevant nonmajor bleeding, but not with gastrointestinal bleeding. The safety and efficacy of apixaban versus warfarin appeared not significantly to be altered by NSAID use. This study warrants more investigation of the effect of NSAIDs on the outcomes of patients treated with apixaban. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00412984.

Propensity score weighting for causal subgroup analysis.

A common goal in comparative effectiveness research is to estimate treatment effects on prespecified subpopulations of patients. Though widely used in medical research, causal inference methods for such subgroup analysis (SGA) remain underdeveloped, particularly in observational studies. In this article, we develop a suite of analytical methods and visualization tools for causal SGA. First, we introduce the estimand of subgroup weighted average treatment effect and provide the corresponding propensity score weighting estimator. We show that balancing covariates within a subgroup bounds the bias of the estimator of subgroup causal effects. Second, we propose to use the overlap weighting (OW) method to achieve exact balance within subgroups. We further propose a method that combines OW and LASSO, to balance the bias-variance tradeoff in SGA. Finally, we design a new diagnostic graph-the Connect-S plot-for visualizing the subgroup covariate balance. Extensive simulation studies are presented to compare the proposed method with several existing methods. We apply the proposed methods to the patient-centered results for uterine fibroids (COMPARE-UF) registry data to evaluate alternative management options for uterine fibroids for relief of symptoms and quality of life.

Effect of alirocumab on cardiovascular outcomes after acute coronary syndromes according to age: an ODYSSEY OUTCOMES trial analysis.

AIMS: Lowering low-density lipoprotein cholesterol (LDL-C) reduces cardiovascular risk irrespective of age, but the evidence is less strong for older patients. METHODS AND RESULTS: This prespecified analysis from ODYSSEY OUTCOMES compared the effect of alirocumab vs. placebo in 18 924 patients with recent acute coronary syndrome (ACS) according to age. We examined the effect of assigned treatment on occurrence of the primary study outcome, a composite of coronary heart disease death, myocardial infarction, ischaemic stroke, or unstable angina requiring hospitalization [major adverse cardiovascular event (MACE)] and all-cause death. Relative risk reductions were consistent for patients ≥65 vs. <65 years for MACE [hazard ratio (HR) 0.78, 95% confidence interval (CI) 0.68-0.91 vs. 0.89, 0.80-1.00; Pinteraction = 0.19] and all-cause death [HR 0.77, 0.62-0.95 vs. 0.94, 0.77-1.15; Pinteraction = 0.46], and consistent for MACE when dichotomizing at age 75 years (HR 0.85, 0.64-1.13 in ≥75 vs. 0.85, 0.78-0.93 in <75, Pinteraction = 0.19). When considering age as a continuous variable in regression models, advancing age increased risk of MACE, as well as the absolute reduction in MACE with alirocumab, with numbers-needed-to-treat for MACE at 3 years of 43 (25-186) at age 45 years, 26 (15-97) at age 75 years, and 12 (6-81) for those at age 85 years. Although adverse events were more frequent in older patients, there were no differences between alirocumab and placebo. CONCLUSION: In patients with recent ACS, alirocumab improves outcomes irrespective of age. Increasing absolute benefit but not harm with advancing age suggests that LDL-C lowering is an important preventive intervention for older patients after ACS.

Efficacy and Safety of Apixaban Versus Warfarin in Patients With Atrial Fibrillation and Extremes in Body Weight.

BACKGROUND: Guidelines caution against the use of non-vitamin K antagonist oral anticoagulants in patients with extremely high (>120 kg) or low (≤60 kg) body weight because of a lack of data in these populations. METHODS: In a post hoc analysis of ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation; n=18 201), a randomized trial comparing apixaban with warfarin for the prevention of stroke in patients with atrial fibrillation, we estimated the randomized treatment effect (apixaban versus warfarin) stratified by body weight (≤60, >60-120, >120 kg) using a Cox regression model and tested the interaction between body weight and randomized treatment. The primary efficacy and safety outcomes were stroke or systemic embolism and major bleeding. RESULTS: Of the 18 139 patients with available weight and outcomes data, 1985 (10.9%) were in the low-weight group (≤60 kg), 15 172 (83.6%) were in the midrange weight group (>60-120 kg), and 982 (5.4%) were in the high-weight group (>120 kg). The treatment effect of apixaban versus warfarin for the efficacy outcomes of stroke/systemic embolism, all-cause death, or myocardial infarction was consistent across the weight spectrum (interaction P value>0.05). For major bleeding, apixaban had a better safety profile than warfarin in all weight categories and even showed a greater relative risk reduction in patients in the low (≤60 kg; HR, 0.55; 95% CI, 0.36-0.82) and midrange (>60-120 kg) weight groups (HR, 0.71; 95% CI, 0.61-0.83; interaction P value=0.016). CONCLUSIONS: Our findings provide evidence that apixaban is efficacious and safe across the spectrum of weight, including in low- (≤60 kg) and high-weight patients (>120 kg). The superiority on efficacy and safety outcomes of apixaban compared with warfarin persists across weight groups, with even greater reductions in major bleeding in patients with atrial fibrillation with low to normal weight as compared with high weight. The superiority of apixaban over warfarin in regard to efficacy and safety for stroke prevention seems to be similar in patients with atrial fibrillation across the spectrum of weight, including in low- and very high-weight patients. Thus, apixaban appears to be appropriate for patients with atrial fibrillation irrespective of body weight. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT00412984.

Clinical consequences of bleeding among individuals with a recent acute coronary syndrome: Insights from the APPRAISE-2 trial.

Patients with a recent acute coronary syndrome (ACS) receiving oral antiplatelets and anticoagulants are at risk for bleeding and subsequent adverse non-bleeding-related events. METHODS: In this post hoc analysis, we evaluated 7,392 high-risk patients (median follow-up 241 days) with a recent ACS randomized to apixaban or placebo in APPRAISE-2. Clinical events during a 30-day period after Thrombolysis in Myocardial Infarction (TIMI) major/minor bleeding were analyzed using unadjusted and adjusted Cox proportional-hazards models. RESULTS: In total, 153 (2.1%) patients experienced TIMI major/minor bleeding during follow-up. Bleeding risk for patients on triple therapy (apixaban, thienopyridine, and aspirin) was increased compared with those on dual therapy (apixaban plus aspirin: hazard ratio [HR] 2.02, 95% CI 1.08-3.79; thienopyridine plus aspirin: HR 1.99, 95% CI 1.41-2.83). Those receiving apixaban/aspirin had similar bleeding risk compared with those receiving thienopyridine/aspirin (HR 1.01, 95% CI 0.53-1.95). Patients who experienced TIMI major/minor bleeding had an increased risk of 30-day all-cause mortality (HR 24.7, 95% CI 15.34-39.66) and ischemic events (HR 6.7, 95% CI 3.14-14.14). CONCLUSIONS: In a contemporary cohort of high-risk patients after ACS, bleeding was associated with a significantly increased risk of subsequent ischemic events and mortality regardless of antithrombotic or anticoagulant strategy. Patients receiving apixaban plus aspirin had a similar bleeding risk compared with those receiving thienopyridine plus aspirin. Interventions to improve outcomes in patients after ACS should include strategies to optimize the reduction in ischemic events while minimizing the risk of bleeding.

Ticagrelor in patients with heart failure after acute coronary syndromes-Insights from the PLATelet inhibition and patient Outcomes (PLATO) trial.

BACKGROUND: Heart failure (HF) following acute coronary syndromes (ACS) is associated with worse prognosis; however, the efficacy and safety of ticagrelor in patients with HF and if ticagrelor influences the risk of new-onset HF are unknown. METHODS: We examined the efficacy and safety of ticagrelor compared to clopidogrel in patients with ACS in the randomized PLATelet inhibition and patient Outcomes (PLATO) trial subdivided by strata: (1) previous HF and/or clinical signs of HF on admission or (2) no HF on admission. The primary outcome was the combination of cardiovascular death, myocardial infarction, or stroke evaluated by multivariable Cox regression models. The safety outcome was major bleeding. New-onset HF was defined as an HF event after discharge in patients without previous HF. RESULTS: Data were available in 18,556 patients, whom 2,862 (15.4%) patients had HF, including 1,584 (8.5%) patients with previous HF. Patients randomized to ticagrelor had lower risk of the composite end point regardless of HF status: hazard ratio (HR) 0.87 (95% CI: 0.73-1.03) in patients with HF and HR 0.84 (95% CI: 0.75-0.93) in patients with no HF (P = .76). Corresponding HR for major bleeding were HR 1.08 (95% CI: 0.87-1.34) and HR 1.03 (95% CI: 0.94-1.14) (P = .71). There was no difference in new-onset HF at 12 months between patients randomized to ticagrelor (4.1%, n = 278) or clopidogrel (4.0%, n = 276). CONCLUSIONS: In patients with ACS, ticagrelor is more efficacious in protecting against new ischemic events and mortality than clopidogrel irrespective of the presence of HF. There is no difference between ticagrelor or clopidogrel treatment in new-onset HF post-ACS.

Intracranial hemorrhage in patients with atrial fibrillation receiving anticoagulation therapy.

We investigated the frequency and characteristics of intracranial hemorrhage (ICH), the factors associated with the risk of ICH, and outcomes post-ICH overall and by randomized treatment. We identified patients with ICH from the overall trial population enrolled in the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation trial who received ≥1 dose of the study drug (n = 18 140). ICH was adjudicated by a central committee. Cox regression models were used to identify factors associated with ICH. ICH occurred in 174 patients; most ICH events were spontaneous (71.7%) versus traumatic (28.3%). Apixaban resulted in significantly less ICH (0.33% per year), regardless of type and location, than warfarin (0.80% per year). Independent factors associated with increased risk of ICH were enrollment in Asia or Latin America, older age, prior stroke/transient ischemic attack, and aspirin use at baseline. Among warfarin-treated patients, the median (25th, 75th percentiles) time from most recent international normalized ratio (INR) to ICH was 13 days (6, 21 days). Median INR prior to ICH was 2.6 (2.1, 3.0); 78.5% of patients had a pre-ICH INR <3.0. After ICH, the modified Rankin scale score at discharge was ≥4 in 55.7% of patients, and the overall mortality rate at 30 days was 43.3% with no difference between apixaban- and warfarin-treated patients. ICH occurred at a rate of 0.80% per year with warfarin regardless of INR control and at a rate of 0.33% per year with apixaban and was associated with high short-term morbidity and mortality. This highlights the clinical relevance of reducing ICH by using apixaban rather than warfarin and avoiding concomitant aspirin, especially in patients of older age. This trial was registered at www.clinicaltrials.gov as #NCT00412984.

Interacting medication use and the treatment effects of apixaban versus warfarin: results from the ARISTOTLE Trial.

Warfarin is dependent on multiple hepatic enzymes for metabolism while apixaban is a substrate for P-glycoprotein (P-gp) transport and hepatic CYP3A4 metabolism. The aim of this analysis was to assess the impact of interacting medication use on the treatment effects of apixaban versus warfarin. Outcomes were compared between apixaban and warfarin using Cox proportional hazards modeling according to the use of interacting medications at randomization in ARISTOTLE (n = 18,201). Interacting medications for apixaban were identified as combined P-gp and 3A4 inhibitors or inducers while interacting medications for warfarin were defined as those highly probable for warfarin potentiation or inhibition. At randomization, 5547 (30.5%) patients were on an interacting medication, including 2722 on apixaban and 2825 on warfarin. Patients using an interacting medication were more likely to be female, taking aspirin, and have a history of prior bleeding and were less likely to have a prior stroke or transient ischemic attack. No significant differences were observed on the treatment effect of apixaban compared with warfarin in patients on and off interacting medications for outcomes including the primary efficacy outcome of stroke or systemic embolism (P for interaction = 0.79) or the primary safety outcome of major bleeding (P for interaction = 0.75). Use of interacting medications with anticoagulants occurs often in patients with atrial fibrillation. Despite the potential for altered exposure, interacting medication use was not associated with a significant change in the efficacy or safety of apixaban compared with warfarin in the ARISTOTLE trial.Trial registration ClinicalTrials.gov, NCT00412984.

Percutaneous coronary intervention and antiplatelet therapy in patients with atrial fibrillation receiving apixaban or warfarin: Insights from the ARISTOTLE trial.

BACKGROUND: We assessed antiplatelet therapy use and outcomes in patients undergoing percutaneous coronary intervention (PCI) during the ARISTOTLE trial. METHODS: Patients were categorized based on the occurrence of PCI during follow-up (median 1.8 years); PCI details and outcomes post-PCI are reported. Of the 18,201 trial participants, 316 (1.7%) underwent PCI (152 in apixaban group, 164 in warfarin group). RESULTS: At the time of PCI, 84% (267) were on study drug (either apixaban or warfarin). Of these, 19% did not stop study drug during PCI, 49% stopped and restarted <5 days post-PCI, and 30% stopped and restarted >5 days post-PCI. At 30 days post-PCI, 35% of patients received dual -antiplatelet therapy (DAPT), 23% received aspirin only, and 13% received a P2Y12 inhibitor only; 29% received no antiplatelet therapy. Triple therapy (DAPT + oral anticoagulant [OAC]) was used in 21% of patients, 23% received OAC only, 15% received OAC plus aspirin, and 9% received OAC plus a P2Y12 inhibitor; 32% received antiplatelet agents without OAC. Post-PCI, patients assigned to apixaban versus warfarin had numerically similar rates of major bleeding (5.93 vs 6.73 events/100 patient-years; P = .95) and stroke (2.74 vs 1.84 events/100 patient-years; P = .62). CONCLUSIONS: PCI occurred infrequently during follow-up. Most patients on study drug at the time of PCI remained on study drug in the peri-PCI period; 19% continued the study drug without interruption. Antiplatelet therapy use post-PCI was variable, although most patients received DAPT. Additional data are needed to guide the use of antithrombotics in patients undergoing PCI.