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. Adults with MG were identified using a validated algorithm. Each patient was matched by age, sex, and geographic area of residence to 5 controls from the general population and from a cohort of individuals with rheumatoid arthritis (RA). Exposure: Patients with MG and matched controls. Main Outcomes and Measures: Main outcomes were COVID-19 infection and related hospitalizations, intensive care unit admissions, and 30-day mortality among patients with MG vs controls. Secondary outcomes were uptake of COVID-19 vaccination among patients with MG vs controls. Results: Among 11 365 233 eligible Ontario residents, 4411 patients with MG (mean [SD] age, 67.7 [15.6] years; 2274 women [51.6%]) were matched to 22 055 general population controls (mean [SD] age, 67.7 [15.6] years; 11 370 women [51.6%]) and 22 055 controls with RA (mean [SD] age, 67.7 [15.6] years; 11 370 women [51.6%]). In the matched cohort, 38 861 of 44 110 individuals (88.1%) were urban residents; in the MG cohort, 3901 (88.4%) were urban residents. Between January 15, 2020, and May 17, 2021, 164 patients with MG (3.7%), 669 general population controls (3.0%), and 668 controls with RA (3.0%) contracted COVID-19. Compared with general population controls and controls with RA, patients with MG had higher rates of COVID-19-associated emergency department visits (36.6% [60 of 164] vs 24.4% [163 of 669] vs 29.9% [200 of 668]), hospital admissions (30.5% [50 of 164] vs 15.1% [101 of 669] vs 20.7% [138 of 668]), and 30-day mortality (14.6% [24 of 164] vs 8.5% [57 of 669] vs 9.9% [66 of 668]). By August 2021, 3540 patients with MG (80.3%) vs 17 913 general population controls (81.2%) had received 2 COVID-19 vaccine doses, and 137 (3.1%) vs 628 (2.8%), respectively had received 1 dose. Of 3461 first vaccine doses for patients with MG, fewer than 6 individuals were hospitalized for MG worsening within 30 days of vaccination. Vaccinated patients with MG had a lower risk than unvaccinated patients with MG of contracting COVID-19 (hazard ratio, 0.43; 95% CI, 0.30-0.60). Conclusions and Relevance: This study suggests that adults with MG who contracted COVID-19 had a higher risk of hospitalization and death compared with matched controls. Vaccine uptake was high, with negligible risk of severe MG exacerbations after vaccination, as well as evidence of effectiveness. The findings support public health policies prioritizing people with MG for vaccination and new COVID-19 therapeutics.

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. We used hierarchical logistic regression modelling to assess the association of patient, surgery, and hospital factors with postoperative troponin testing, while accounting for clustering at the hospital level. We characterized hospital-level variation by the intraclass correlation coefficient (ICC), which was adjusted for various characteristics. RESULTS: The cohort included 176,454 eligible patients. Hospital-specific adjusted testing rates ranged from 0-20.1% for orthopedic surgery, 0-43.8% for colorectal surgery, and 19.6-88.0% for vascular surgery. Older age, urgent surgery status, and surgery duration were consistently associated with higher rates of testing for all three surgeries. Higher Revised Cardiac Risk Index scores were associated with higher odds of testing for orthopedic and colorectal surgery, but not for vascular surgery. Even after adjustment, the ICCs were 9.2%, 7.4%, and 24.1% for orthopedic, general, and vascular surgery, respectively. CONCLUSIONS: Troponin testing varied substantially across hospitals for selected major noncardiac surgery procedures even after accounting for differences in patient-level cardiac risk factors. Our observations lend support to a more standardized approach for troponin testing after noncardiac surgery.

RéSUMé: CONTEXTE: Les directives de pratique internationales émettent différentes recommandations en ce qui concerne les dosages postopératoires de troponines afin de détecter l'infarctus du myocarde et les lésions myocardiques périopératoires après une chirurgie non cardiaque. Pour mieux comprendre les habitudes de test actuelles, nous avons évalué les prédicteurs de dosage de troponines de routine après trois chirurgies non cardiaques majeures couramment réalisées. MéTHODE: Nous avons réalisé une étude de cohorte historique basée sur la population d'adultes bénéficiant d'une chirurgie orthopédique, colorectale ou vasculaire majeure en Ontario, au Canada, entre le 1er janvier 2010 et le 31 décembre 2017. Nous avons utilisé un modèle de régression logistique hiérarchique afin d'évaluer l'association des facteurs liés au patient, à la chirurgie et à l'hôpital avec les dosages de troponines postopératoires, tout en tenant compte des groupements au niveau hospitalier. Nous avons caractérisé la variation hospitalière par le coefficient de corrélation intraclasse (CCI), qui a été ajusté pour tenir compte de diverses caractéristiques. RéSULTATS: La cohorte comprenait 176 454 patients éligibles. Les taux de tests ajustés propres à l'hôpital variaient de 0 à 20,1 % pour les chirurgies orthopédiques, de 0 à 43,8 % pour les chirurgies colorectales et de 19,6 à 88,0 % pour les chirurgies vasculaires. Un âge plus avancé, un statut de chirurgie urgente et la durée de la chirurgie étaient systématiquement associés à des taux plus élevés de dosages pour les trois chirurgies. Des scores plus élevés sur l'Indice de risque cardiaque révisé étaient associés à des probabilités plus élevées de dosages pour les chirurgies orthopédiques et colorectales, mais pas pour les chirurgies vasculaires. Même après ajustement, les CCI étaient de 9,2 %, 7,4 % et 24,1 % pour les chirurgies orthopédiques, générales et vasculaires, respectivement. CONCLUSION: Les dosages de troponines varient considérablement d'un hôpital à l'autre pour certaines interventions chirurgicales non cardiaques majeures, même après avoir pris en compte les différences dans les facteurs de risque cardiaques liés au patient. Nos observations appuient une approche plus standardisée des dosages de troponines après une chirurgie non cardiaque.

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. The primary outcomes were the proportion of patients recommended for testing based on the guidelines and rates of troponin testing within 2 days of surgery. RESULTS: We identified 257,704 patients who underwent noncardiac surgery. Mean age was 66.4 ± 11.9 years, and 12.4% underwent urgent surgery. Applying the CCS guidelines, 71.2% of elective surgery patients and 81.0% of urgent surgery patients would have met recommendations for postoperative troponin screening, whereas 10.8% and 27.1% received postoperative troponin testing, respectively. Most elective surgery patients met recommendations for testing based on the age criterion (54.9%), followed by diabetes (24.6%) and high-risk surgery (22.7%) criteria. Troponin testing varied substantially by types of surgery: highest for open abdominal aortic aneurisms and lowest for hysterectomies. CONCLUSIONS: Based on the CCS guidelines, most patients undergoing the subset of surgeries assessed would have met recommendations for routine troponin testing. In contrast, routine troponin testing before guideline adoption was done infrequently in Ontario, with substantial variations based on the surgery type.

INTRODUCTION: En 2017, la Société canadienne de cardiologie (SCC) a publié des lignes directrices dont les recommandations portaient sur la surveillance de la troponine en phase postopératoire chez les patients exposés à un risque accru de subir une intervention chirurgicale non cardiaque importante. L'objectif de la présente étude était d'évaluer le nombre de patients subissant une intervention chirurgicale non cardiaque importante qui répondraient aux recommandations sur le dosage de la troponine et de déterminer la fréquence des dosages de la troponine avant l'adoption des lignes directrices. MÉTHODES: Nous avons mené une étude observationnelle rétrospective auprès de patients âgés de 40 à 105 ans subissant des interventions chirurgicales non cardiaques importantes, à savoir des interventions de chirurgie orthopédique, de chirurgie gynécologique, de chirurgie générale, de chirurgie urologique, de chirurgie vasculaire et de chirurgie thoracique en Ontario, au Canada, du 1er janvier 2010 au 31 décembre 2017. Les principaux critères d'évaluation étaient le nombre de patients pour qui le dosage était recommandé selon les lignes directrices, et la fréquence des dosages de la troponine dans les deux jours après l'intervention chirurgicale. RÉSULTATS: Nous avons relevé 257 704 patients qui avaient subi une intervention chirurgicale non cardiaque. L'âge moyen était de 66,4 ± 11,9 ans, et 12,4 % avaient subi une intervention chirurgicale urgente. En appliquant les lignes directrices de la SCC, 71,2 % des patients avaient subi une intervention chirurgicale élective et 81,0 % des patients qui avaient subi une intervention chirurgicale urgente répondaient aux recommandations de dépistage de la troponine en phase postopératoire, alors que respectivement 10,8 % et 27,1 % avaient reçu le dosage de la troponine en phase postopératoire. La plupart des patients qui avaient subi une intervention chirurgicale élective répondaient aux recommandations sur le dosage selon le critère d'âge (54,9 %), puis selon le critère de diabète (24,6 %) et le critère d'intervention chirurgicale à risque élevé (22,7 %). Le dosage de la troponine variait de façon substantielle selon le type d'intervention chirurgicale : le dosage le plus élevé lors des traitements chirurgicaux ouverts des anévrismes de l'artère abdominale et le dosage le plus faible lors d'hystérectomies. CONCLUSIONS: Selon les lignes directrices de la SCC, la plupart des patients qui subissaient les interventions chirurgicales évaluées avaient répondu aux recommandations de dosage systématique de la troponine. En revanche, le dosage systématique de la troponine avant l'adoption des lignes directrices était rarement réalisé en Ontario, et des variations substantielles selon le type d'intervention chirurgicale étaient observées.

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. METHODS: The study population included all AF patients with continuous DOAC use in Ontario, Canada, ≥66 years, from April 1, 2017 to March 31, 2018. Concurrent use of amiodarone or diltiazem was determined by identifying the presence of an overlapping prescription. Multivariable logistic regression models were used to identify predictors of amiodarone or diltiazem use. RESULTS: In total, 5,390 AF patients, ≥66 years, with continuous DOAC use were identified. Amiodarone was co-prescribed in 6.4% patients and diltiazem was co-prescribed in 11.2% patients. Prior percutaneous coronary intervention (PCI) and coronary artery bypass surgery (CABG) were associated with significantly increased odds of amiodarone co-use (OR 2.51 [95% CI 1.54, 4.09], p = 0.0002 and OR 5.28 [95% CI 3.52, 7.93], p= <0.001, respectively). Patients with a heart failure (HF) history also had increased co-use of amiodarone (OR 2.05 [95% CI 1.57, 2.67], p < 0.001). The presence of chronic obstructive pulmonary disease (COPD) was associated with significantly increased odds of diltiazem co-use (OR 1.58 [95% CI 1.31, 1.9], p=<0.001). CONCLUSIONS: Among AF patients with continuous DOAC use, amiodarone was co-prescribed in 1 in 16 patients and diltiazem was co-prescribed in 1 in 9 patients. Predictors such as history of HF, PCI, CABG or COPD help identify vulnerable populations at increased risk of DDIs.

Same-Day Discharge After Elective Percutaneous Coronary Interventions in Ontario, Canada.

Background To manage overcrowding and bed shortages in Canadian hospitals, same-day discharge (SDD) after percutaneous coronary intervention (PCI) has emerged as a solution to improve resource utilization. However, limited information exists regarding current trends, hospital variation, and safety of SDD PCI in Canada. Methods and Results We evaluated outpatients undergoing elective PCI in Ontario, Canada, from October 2008 to March 2016. SDD was defined when patients were discharged on the day of PCI, and non-SDD was defined as those patients who had 1 overnight stay. The primary outcome was 30-day all-cause death or hospitalization for acute coronary syndrome. Inverse probability of treatment weighting with propensity score was used to account for differences in baseline and clinical characteristics between SDD and non-SDD groups. Among 35 972 patients who underwent elective PCI at 17 PCI centers in Ontario, 10 801 patients (30%) had SDD PCI and 25 121 patients (70%) had non-SDD PCI. Substantial hospital variation for SDD PCI was observed, ranging from 0% to 87% during the study period. In the propensity-weighted cohort, SDD patients had no significant difference in 30-day rates of death or hospitalization for acute coronary syndrome (1.3% versus 1.6%; hazard ratio: 0.84 [95% CI, 0.65-1.08]; P=0.17) compared with non-SDD patients. SDD and non-SDD patients also had no significant difference in 30-day rates of mortality or coronary revascularization. Conclusions In this large population-based cohort of elective PCI patients, we demonstrated the safety of SDD PCI. Increased adoption of this strategy could lead to improved bed-flow efficiency and substantial savings for the Canadian healthcare system without comprising outcomes.

The Risk of Cardiovascular Events on Cannabis' Highest Day.

Knowledge of the acute cardiovascular effects of cannabis consumption remains largely unknown and is important given the changing landscape of legalization of recreational cannabis use. "4/20" is an annual event where many individuals gather to consume cannabis. An increased risk of adverse health events such as motor vehicle accidents has previously been reported to occur on "4/20." In this study, population-based administrative databases in Ontario, Canada, were used to evaluate the association between "4/20" and cardiovascular events. An increased risk of cardiovascular events on a population level was not observed on "4/20." Additional research into the changes in the prevalence of the use of cannabis with recreational legalization and acute and chronic risk with cannabis use is suggested.

Clinical Outcomes of Plavix and Generic Clopidogrel for Patients Hospitalized With an Acute Coronary Syndrome.

BACKGROUND: Clopidogrel is one of the most commonly prescribed medications because of its ability to improve clinical outcomes for a broad range of cardiovascular conditions. After patent protection expired for Plavix in 2012, many healthcare systems adopted generic clopidogrel as a strategy to reduce healthcare costs. METHODS AND RESULTS: We conducted a population-based observational study to determine whether generic clopidogrel was noninferior to Plavix. Patients who were hospitalized with an acute coronary syndrome (ACS) from 2009 to 2014 in Ontario, Canada, >65 years, survived ≥7 days after discharge, were eligible for inclusion. The primary outcome was a composite of death and recurrent ACS at 1 year. The noninferiority margin was prespecified at a relative hazard difference of 10%. Inverse propensity of treatment weighting of the propensity score was used to account for differences in baseline characteristics between the treatment groups. The effect of clopidogrel on the hazard of clinical outcomes was estimated using a Cox proportional hazards model within the propensity-weighted cohort using Plavix as a reference. Our study included 24 530 patients with ACS, 12 643 were prescribed Plavix and 11 887 were prescribed generic clopidogrel at hospital discharge. The mean age was 77 years, 57% were men, and 21% had an ST-segment-elevation myocardial infarction. At 1 year, 17.6% of patients prescribed Plavix and 17.9% of patients prescribed clopidogrel experienced the primary outcome (hazard ratio, 1.02; 95% confidence interval, 0.96-1.08; P=0.005 for noninferiority). No significant differences between rates of death, all-cause readmission, ACS, stroke or transient ischemic attack, or bleeding were observed. CONCLUSIONS: Generic clopidogrel was noninferior to Plavix with respect to the composite end point of death and recurrent hospitalization for ACS at 1 year among adults >65 years after an ACS hospitalization. Our findings support generic clopidogrel in ACS, which could lead to substantial healthcare cost savings.

Population-Based Study on Patterns of Cardiac Stress Testing After Percutaneous Coronary Intervention.

BACKGROUND: The appropriate use criteria considers cardiac stress testing within 2 years after percutaneous coronary intervention (PCI) to be rarely appropriate, unless prompted by symptoms or change in clinical status. Little is known about the patterns of cardiac stress testing after PCI in the single-payer Canadian healthcare system, where mechanisms for reimbursement are different from the United States. METHODS AND RESULTS: Frequency and timing of cardiac stress testing within 2 years of PCI performed between April 2004 and March 2013 in Ontario, Canada, was determined from linked provincial databases. Subsequent rates of coronary angiography and revascularization after stress testing were ascertained. Of the 112 691 patients with PCI, 67 442 (59.8%) underwent at least 1 stress test, with 38 267 (34.0%) undergoing repeat stress testing (ie, >1 stress test) within 2 years. Patients who underwent stress testing were younger, had less medical comorbidities, were more likely to reside in urban areas, and had higher incomes. Spikes in incidence of repeat stress testing were observed at 3 to 4 months, 6 to 7 months, and 12 to 13 months after the prior stress test. Of those tested, only 5.9% underwent subsequent coronary angiography, and only 3.1% underwent repeat revascularization within 60 days of stress testing. CONCLUSIONS: More than half of all patients undergo cardiac stress testing within 2 years of PCI, with one third undergoing repeat stress tests. Only 1 of 30 tested patients underwent repeat revascularization. These findings reinforce the appropriate use criteria recommendations against routine stress testing after PCI. Further work is needed to aid with the selection of patients most likely to benefit from stress testing after PCI.

Outcomes of Women and Men With Acute Coronary Syndrome Treated With and Without Percutaneous Coronary Revascularization.

BACKGROUND: Women hospitalized with a non-ST segment elevation acute coronary syndrome (ACS) have worse clinical outcomes compared with men. An early invasive strategy with prompt coronary revascularization may mitigate sex differences in outcomes. However, few contemporary studies have evaluated whether clinical outcomes differ between women and men presenting with ACS treated with an early invasive strategy. METHODS AND RESULTS: A population-based cohort of hospitalized ACS patients who received prompt cardiac catheterization from 2008 to 2011 in Ontario, Canada and followed for up to 2 years was studied. Clinical outcomes were compared between men and women, stratified by the use of coronary revascularization. Inverse probability weighting using the propensity score accounted for measured differences in baseline characteristics between men and women. Among the 23 473 ACS patients who received cardiac catheterization during an index hospitalization, 66.1% of men and 51.8% of women received coronary revascularization during the same hospitalization. In the propensity-weighted cohort of patients who received coronary revascularization, the 1-year rate of death or recurrent ACS was 10.6% for men (referent) compared with 13.1% for women (hazard ratio 1.24; 95% CI 1.16-1.33). In contrast, outcomes for patients who did not receive coronary revascularization did not differ significantly between women and men at 1 year (17.8% versus 16.9%; hazard ratio 1.06; 95% CI 0.99-1.14) or at longer follow-up. CONCLUSIONS: An increased risk of adverse clinical outcomes was observed for women with ACS undergoing an early invasive strategy and coronary revascularization compared with men.

Long-term clinical outcomes and predictors for survivors of out-of-hospital cardiac arrest.

AIMS: Improvement in resuscitation efforts has translated to an increasing number of survivors after out-of-hospital cardiac arrest (OHCA). Our objectives were to assess the long-term outcomes and predictors of mortality for patients who survived OHCA. METHODS: We conducted a population-based cohort study linking the Toronto RescuNET cardiac arrest database with administrative databases in Ontario, Canada. We included patients with non-traumatic OHCA from December 1, 2005 to December 31, 2014. The primary outcomes were mortality at 1 year and 3 years. Cox proportional hazard models were constructed to evaluate the predictors of mortality. RESULTS: Among the 28,611 OHCA patients who received treatment at the scene of arrest, 1591 patients survived to hospital discharge. During hospitalization, 36% received coronary revascularizations and 27% received an implantable cardioverter defibrillator. At one year after discharge, 12.6% of patients had died and 37.3% were readmitted. At 3 years, mortality rate was 20% and all-cause readmission rate was 54.1%. Older age and a history of cancer were associated with higher risk of 3-year mortality. Shockable rhythm at presentation (hazard ratio [HR] 0.62, 95% CI 0.45-0.85), use of coronary revascularization (HR 0.37, 95% CI 0.28-0.51) or implantable cardioverter defibrillator (HR 0.28, 95% CI 0.20-0.41) was associated with substantially lower 3-year mortality. Prior cardiac conditions and other arrest characteristics were not associated with long-term mortality. CONCLUSIONS: Survivors of OHCA face significant morbidity and mortality after hospital discharge. Clinical trials are needed to evaluate the potential benefits of invasive cardiac procedures in OHCA survivors.