Social inequalities in COVID-19 death by area-level income in 11.2 million people in Ontario, Canada: patterns over time and the mediating role of vaccination.

Knowledge of patterns in COVID-19 deaths by area-level income over time and the mediating role of vaccination in inequality patterns remains limited. We used data from a population-based retrospective cohort of 11,248,572 adults in Ontario, Canada. Cause-specific hazard models were used examine the relationship between income 2016 Census at the dissemination area level) and COVID-19 deaths between March-1-2020 and January-30-2022, stratified by wave.

Protection of prior SARS-CoV-2 infection, COVID-19 boosters, and hybrid immunity against Omicron severe illness: A population-based cohort study of five million residents in Canada.

Background: Evidence on protection of different patterns of infection- and vaccine-acquired immunity against Omicron-associated severe illness is useful in planning booster vaccination strategies. We examined protection of prior SARS-CoV-2 infection, a third or a fourth COVID-19 vaccine dose, and hybrid immunity against Omicron-associated severe illness.

Methods And Findings: This population-based cohort study followed five million individuals with at least one SARS-CoV-2 RT-PCR test before November 21, 2021 until an Omicron-associatedhospitalization or death.

Outcomes of COVID-19 Infection and Vaccination Among Individuals With Myasthenia Gravis.

Importance: There are limited data regarding COVID-19 outcomes and vaccine uptake and safety among people with myasthenia gravis (MG).

Objective: To investigate COVID-19-related outcomes and vaccine uptake among a population-based sample of adults with MG.

Design, Setting, And Participants: This population-based, matched cohort study in Ontario, Canada, used administrative health data from January 15, 2020, and August 31, 2021.

Epidemiology of COVID-19 and Its Cardiac and Neurologic Complications Among Chinese and South Asians in Ontario: Waves 1, 2, and 3.

Background: Although we had previously reported the cardiac and neurologic outcomes of Chinese and South Asian Ontarians in wave 1 of COVID-19, data on subsequent waves of COVID-19 remain unexamined. This is an extension study of this cohort in waves 2 and 3.

Methods: We identified adult Ontarians with a positive COVID-19 polymerase chain reaction test from January 1, 2020 to June 30, 2021, and they were classified as being Chinese or South Asian using a validated surname algorithm; we compared their outcomes of mortality, and cardiac and neurologic complications with those of the general population using multivariable logistic regression models.

Troponin testing after noncardiac surgery: a population-based historical cohort study on variation and factors associated with testing in Ontario.

Background: International practice guidelines make different recommendations for postoperative troponin testing to detect perioperative myocardial infarction and myocardial injury after noncardiac surgery. To gain insights into current testing patterns, we evaluated predictors of routine troponin testing after three commonly performed major noncardiac surgeries.

Methods: We conducted a population-based historical cohort study of adults having major orthopedic, colorectal, or vascular surgery in Ontario, Canada from 1 January 2010 to 31 December 2017.

Development of Acute Myocardial Infarction Mortality and Readmission Models for Public Reporting on Hospital Performance in Canada.

Background: Given changes in the care and outcomes of acute myocardial infarction (AMI) patients over the past several decades, we sought to develop prediction models that could be used to generate accurate risk-adjusted mortality and readmission outcomes for hospitals in current practice across Canada.

Methods: A Canadian national expert panel was convened to define appropriate AMI patients for reporting and develop prediction models. Preliminary candidate variable evaluation was conducted using Ontario patients hospitalized with a most responsible diagnosis of AMI from April 1, 2015 to March 31, 2018.

Renin-angiotensin-aldosterone system inhibitors and major cardiovascular events and acute kidney injury in patients with coronary artery disease.

Background: Renin-angiotensin-aldosterone system inhibitors (RAASIs) are recommended for most patients with coronary artery disease (CAD). However, there is debate across guidelines as to which patients with CAD benefit the most from these agents. This study investigated the association between RAASIs and cardiovascular outcomes and acute kidney injury in a contemporary cohort of patients with CAD.

Troponin Testing After Noncardiac Surgery in Ontario: An Observational Study.

Background: In 2017, the Canadian Cardiovascular Society (CCS) published guidelines recommending postoperative troponin surveillance in higher-risk patients having major noncardiac surgery. The objective of this study was to evaluate the proportion of major noncardiac surgery patients that would meet recommendations for troponin testing and to assess the rates of troponin testing before guideline adoption.

Methods: We conducted a retrospective observational study of patients age 40 to 105 undergoing a subset of major noncardiac surgeries that included orthopedics, gynecology, general, urology, vascular, and thoracic surgeries in Ontario, Canada from January 1, 2010 to December 31, 2017.

COVID-19 and its Cardiac and Neurological Complications among Ontario Visible Minorities.

Background: Due to lack of data on the epidemiology, cardiac, and neurological complications among Ontario visible minorities (Chinese and South Asians) affected by coronavirus disease (COVID-19), this population-based retrospective study was undertaken to study them systematically.

Methods: From January 1, 2020 to September 30, 2020 using the last name algorithm to identify Ontario Chinese and South Asians who were tested positive by PCR for COVID-19, their demographics, cardiac, and neurological complications including hospitalization and emergency visit rates were analyzed compared to the general population.

Results: Chinese (N = 1,186) with COVID-19 were found to be older (mean age 50.

Prescribing of two potentially interacting cardiovascular medications in atrial fibrillation patients on direct oral anticoagulants.

Background: Amiodarone and diltiazem are commonly recommended cardiovascular medications for use in atrial fibrillation (AF) patients. They are known to have drug-drug interactions (DDIs) with direct oral anticoagulants (DOACs). We aimed to evaluate frequency of use of amiodarone or diltiazem among continuous users of DOACs in AF patients and to determine factors associated with their co-use.

Association Between Adherence to Fractional Flow Reserve Treatment Thresholds and Major Adverse Cardiac Events in Patients With Coronary Artery Disease.

Importance: Fractional flow reserve (FFR) is an invasive measurement used to assess the potential of a coronary stenosis to induce myocardial ischemia and guide decisions for percutaneous coronary intervention (PCI). It is not known whether established FFR thresholds for PCI are adhered to in routine interventional practice and whether adherence to these thresholds is associated with better clinical outcomes.

Objective: To assess the adherence to evidence-based FFR thresholds for PCI and its association with clinical outcomes.

Use of Cardiac Noninvasive Testing After Emergency Department Discharge: Association of Hospital Network Testing Intensity and Outcomes in Ontario, Canada.

Background The relationship between noninvasive cardiac diagnostic testing intensity and downstream clinical outcomes is unclear. Our objective was to examine the relationship between hospital network noninvasive cardiac diagnostic testing intensity and downstream clinical outcomes in patients who were discharged from the emergency department after assessment for chest pain. Methods and Results We employed a retrospective cohort study design of 387 809 patients evaluated for chest pain in the emergency department between April 1, 2010 and March 31, 2016.

Low-Density Lipoprotein Cholesterol and Adverse Cardiovascular Events After Percutaneous Coronary Intervention.

Background: After percutaneous coronary interventions (PCIs), patients remain at high risk of developing late cardiovascular events. Although controlling low-density lipoprotein cholesterol (LDL-C) may improve outcomes after PCI, practice guidelines do not have specific recommendations on LDL-C management for this subgroup.

Objectives: The purpose of this study was to evaluate LDL-C testing and levels after PCIs, and to assess the association between LDL-C and longer-term cardiovascular events after PCIs.

Population Trends in All-Cause Mortality and Cause Specific-Death With Incident Atrial Fibrillation.

BACKGROUND Limited studies have evaluated population-level temporal trends in mortality and cause of death in patients with contemporary managed atrial fibrillation. This study reports the temporal trends in 1-year overall and cause-specific mortality in patients with incident atrial fibrillation. METHODS AND RESULTS Patients with incident atrial fibrillation presenting to an emergency department or hospitalized in Ontario, Canada, were identified in population-level linked administrative databases that included data on vital statistics and cause of death.

Healthcare costs and resource utilization associated with treatment of out-of-hospital cardiac arrest.

Background: The management of out-of-hospital cardiac arrest (OHCA) patients requires the coordination of prehospital, in-hospital and post-discharge teams. Data reporting a comprehensive analysis of all costs associated with treating OHCA are scarce. We aimed to describe the total costs (and their components) related to the management of OHCA patients.

Clinical Outcomes With Beta-Blocker Use in Patients With Recent History of Myocardial Infarction.

Background: It is uncertain whether beta-blockers (BBs) are beneficial in contemporary stable patients with prior myocardial infarction (MI). Therefore, we sought to examine the effectiveness of BB use in this population.

Methods: We conducted a cohort study with the use of administrative databases of patients ≥ 65 years of age, alive on April 1, 2012 (index date) with a hospital discharge diagnosis of MI within the previous 3 years.

Calibration and discrimination of the Framingham Risk Score and the Pooled Cohort Equations.

Background: Although accurate risk prediction is essential in guiding treatment decisions in primary prevention of atherosclerotic cardiovascular disease, the accuracy of the Framingham Risk Score (recommended by a Canadian guideline) and the Pooled Cohort Equations (recommended by US guidelines) has not been assessed in a large contemporary Canadian population. Our primary objective was to assess the calibration and discrimination of the Framingham Risk Score and Pooled Cohort Equations in Ontario, Canada.

Methods: We conducted an observational study involving Ontario residents aged 40 to 79 years, without a history of atherosclerotic cardiovascular disease, who underwent cholesterol testing and blood pressure measurement from Jan.

Evaluation of Machine Learning Algorithms for Predicting Readmission After Acute Myocardial Infarction Using Routinely Collected Clinical Data.

Background: The ability to predict readmission accurately after hospitalization for acute myocardial infarction (AMI) is limited in current statistical models. Machine-learning (ML) methods have shown improved predictive ability in various clinical contexts, but their utility in predicting readmission after hospitalization for AMI is unknown.

Methods: Using detailed clinical information collected from patients hospitalized with AMI, we evaluated 6 ML algorithms (logistic regression, naïve Bayes, support vector machines, random forest, gradient boosting, and deep neural networks) to predict readmission within 30 days and 1 year of discharge.

Readmission and Mortality After Hospitalization for Myocardial Infarction and Heart Failure.

Background: Readmission rates after acute myocardial infarction (AMI) and heart failure (HF) hospitalizations have decreased in the United States since the implementation of the Hospital Readmissions Reduction Program.

Objectives: This study was designed to examine the temporal trends of readmission and mortality after AMI and HF in Ontario, Canada, where reducing hospital readmissions has not had a policy incentive.

Methods: The cohort was comprised of AMI or HF patients 65 years of age or older who had been hospitalized from 2006 to 2017.

Utilization of Advanced Cardiovascular Therapies in the United States and Canada: An Observational Study of New York and Ontario Administrative Data.

Background: Endovascular aortic aneurysm repair (EVAR), left ventricular assist device (LVAD), and transcatheter aortic valve replacement (TAVR) are expensive cardiovascular technologies with potential to benefit large numbers of patients. There are few population-based studies comparing utilization between countries. Our objective was to compare patient characteristics and utilization patterns of EVAR, LVAD, and TAVR in Ontario, Canada, and New York State, United States.

Clinical outcomes for chest pain patients discharged home from emergency departments using high-sensitivity versus conventional cardiac troponin assays.

Background: High-sensitivity cardiac troponin (hs-cTn) assays enhance detection of lower circulating troponin concentrations, but the impact on outcomes in clinical practice is unclear. Our objective was to compare outcomes of chest pain patients discharged from emergency departments (EDs) using hs-cTn and conventional troponin (cTn) assays.

Methods: We conducted an observational study of chest pain patients aged 40-105 years who presented to an ED from April 1, 2013, to March 31, 2017, and were discharged home.

Real-world risk of cardiovascular outcomes associated with hypertriglyceridaemia among individuals with atherosclerotic cardiovascular disease and potential eligibility for emerging therapies.

Aims: Hypertriglyceridaemia in patients with atherosclerotic cardiovascular disease (ASCVD) has been in focus following the REDUCE-IT trial showing benefit with icosapent ethyl. Among individuals with prevalent ASCVD, we sought to quantify the contemporary, real-world risk of ASCVD events associated with hypertriglyceridaemia, as well as estimate icosapent ethyl eligibility and compare trial participants with REDUCE-IT-like individuals in the population.

Methods And Results: We examined data from 2 424 865 adults with lipid panels in the Ontario population.